Volume 12, Issue 2, December 1987

Transcription

BSOVE
12( 2):
ISSN
505- 585 ( 1987)
0146- 6429
Bulletin of the
SOCIETY OF
VECTOR ECOLOGISTS
r,
1
z.
Volume 12, Number 2
,
7
December,
1987
BULLETIN OF THE
SOCIETY OF VECTOR ECOLOGISTS
Volume 12- Number 2 December 1987
Minoo B. Maim, Production Manager
James P. Webb, Ph.D., Editor
County Vector Control District
13001 Garden Grove Boulevard
Environmental Management Branch
Orange
Garden Grove, CA
California State Department of Health Services
Los Angeles, CA 90026
92643
EDITORIAL BOARD
Dr. Mir S. Mulla, Chairman,
University of California
Riverside, CA
University
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Institute
Oklahoma
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University
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West
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Public
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University of North Dakota
Grand Forks, North Dakota
BULLETIN
OF THE
SOCIETY OF VECTOR ECOLOGISTS
VOLUME
12
DECEMBER,
1987
NUMBER 2
CONTENTS
In Memoriam - Cornelius B.
Philip ( 1900- 1987)
iv
Letter to the Editor
Photograph
of the
Photograph
of
vi
1st European Region
the 2nd European
Meeting, Montpellier,
Region Meeting, Heidelberg,
Submitted
Laboratory Flight Ability
of
Aedes
triseriatus (
FRANCE, 1986
vii
WEST GERMANY, 1987
viii
Papers
Say)
J. L. Clarke, III
and
W. A.
Rowley
505
The Effect of Immature Mosquitoes on Oviposition by Culex pipiens quinquefasciatus and Culiseta
incidens ( Diptera: Culicidae) in the Field
Pattern
Thelytoky Acquisition
of
in
T. R. Wilmot, S. E. Cope,
Muscidifurax
raptor
Girault
and
and
Pteromalidae)
Some Quantitative Aspects
of
Inheritance in
A. R. Barr
512
Sanders ( Hymenoptera:
Breeding Synanthropic Fly Parasitoids
E. F. Legner
517
E. F. Legner
528
Medically Important and Other Ectoparasitic Acarines on Vertebrates from Santa Catalina Island,
California
S. G. Bennett
Scientific
534
Note
The Influence of Host Behavior on Sandfly ( Lutzomyia longipalpis) Feeding Success on Laboratory
Mice
R. E. Coleman
and
J. D. Edman
539
Proceedings
1st European SOVE Branch Meeting, Montpellier, FRANCE
11- 12 September, 1986
Malaria Transmission in the Three Sites
Savanna,
a
Rice Field,
and the
Surrounding
the Area of Bobo-Dioulasso ( Burkina Faso):
V. Robert, P. Gazin,
City
The
P. Camevale
541
J. Pilaski
544
Essais de Modelisation de I:Ingestion des Parlicules par les Larves du Complexe Simulium damnosum:
Simuliidae)
P. Elsen
Dip
554
Contributions to the
Ecology
of
and
Tahyna Virus in Central Europe
18th Annual SOVE Conference, University of California, Riverside
19- 21 November,
Importance
of
Vector
The Future Status
Overwintering
of
Overwintering
Arbovin>ses
Mechanisms
of
to
1986
Disease Maintenance
in North America
North American Culiseta
Future Operational Considerations
R. D. Sjogren, D. J. Dobbert,
W. C. Reeves
561
W. C. Reeves
564
W. K. Reisen
568
S. Palchick
580
and
SOVE Symposium, AMCA Annual Meeting, Seattle, Washington
31 March, 1987
Manpower Needs in Disease Endemic Countries
R. Slooff
584
DECEMBER, 1987
NUMBER 2
IN
VOLUME 12
MEMORIAM1
Cornelius Becker Philip
1900- 1987
VINO
on
Cornelius( Neil"} B. Philip died in San Francisco
January 8, 1987, after an illness of several months.
Neil was born in Fort Lupton, Colorado, on June
teaches who allowed him to collect insects in the school
during study hours. He obtained a Bachelor of
Science degree from the University of Nebraska in
1923, and Doctor.of Philosophy degree in entomology
from the University of Minnesota in 1930.
yard
12, 1900. His preoccupation with natural histo
•
y began
early in life when he spent countless hours collecting
insects and other animals. In 1918, he graduated from
Prior to completion of his graduate studies, Neil
Long Beach Polytechnic High in California, where his
budding interest in biology had been encouraged by a
accepted a temporary appointment with the Rockefeller
West African Yellow Fever Commission in Lagos,
The American Society of Parasitologists and the Journal of Parasitology are thanked for permission to reprint this
article.
iv
VOLUME 12
DECEMBER, 1987
Nigeria, from 1928
1929.
The
NUMBER 2
following year, he
highly productive
poisoning disease of canines ( with Hadlow and Hughes
in 1953); and providing the first demonstration of
career as a medical entomologist/parasitologist with the
canine ehrlichiosis in the United States ( with Ewing in
began
U.
long (
a
S.
Public
and
Service Rocky
Health
himself
established
rickettcial agents
on
years)
in Hamilton, Montana.
Laboratory
he
to
40- 1/ 2
they
Tabanidae ( horse
as an
During
1964). In 1953, he served as President of the American
Society of Parasitologists, and his presidential address
this period
on ticks and the
authority
transmit, as
Mountain
well as
entitled, "
a world expert
`
deer flies).
and
In World War II, Neil
borne salmon poisoning disease" was published in the
to the U. S.
was assigned
Journal of Parasitology two years later.
Typhus Commission,
the
and for his efforts he was awarded
U. S. Typhus Commission Medal in Manila, 1945,
for" exceptionally meritorious service"
investigations on the epidemiology and
rendered
Neil' s contributions to" tabanidology" were just as
during
served
Laboratory from
by
After
Welfare.
career
second
Department
of
of
as
Entomology
long
studies of the
biosystematics
10 book
including 26
300
scientific
works
more than
60
disease
notable
Slightly
percent concerned
parasitological
transmitted
and
Conference on Diseases in Nature Communicable to
by
that
proof
by
two
actively in
Man and the American Society of Rickettsiologists and
Rickettsial Diseases.
and served as
years(
1927- 1987),
(
over
that
Fountain
susceptibility
Kilpatrick in
of
in
horses
1941);
book
Parasitol. 62: 504-509), and in a Festschrift compiled
in his honor by Arnaud and Lane ( 1985, Myia 3:
1- 714).
In 1922, Neil met and married Gladys Helen Hill,
ticks, mites, and animal
who steadfastly supported his scientific endeavors for
and
A few
them.
of
of
include
fever
yellow
his
the next 64 years while raising a family of four children.
more
the
virus
West
subsequently
first
He is survived by Gladys, two daughters ( Bonnie Dee
be
and Jo Joyce), two sons( Robert and Gordon), a brother
( George), 15 grandchildren, and 6 great-grandchildren.
can
African
He also leaves behind many colleagues and friends who
benefited immeasurably from his constant encourage-
shown
the
1941)
and
to this
laying
the
virus ( with
the
merit as well as his generosity in sharing with them his
time and
experimental
Cox
Chloromycetin®
and
framework for the
( Chloramphenicol)
treatment
Smadel, Woodward,
of
scrub
for
typhus (
broad knowledge.
Moreover, Neil' s keen
sense of humor and his sage counsel will be missed
and
sorely by all of us who were privileged to have known
contemporary classification of typhus- like organisms
Rickettsiales) ( 1943); demonstrating the efficacy of
prophylaxis
have been documented recently by Jellison and Kohls
1973, Exp. Parasitol. 33: 407-423), Collins ( 1976, J.
these,
nondomestic
were
Neil' s numerous achievements
miscellany,
one- half of his
various
contributions
naturally infected ( 1930);
Cox
member of both the International Northwestern
to be
fast demonstration of
St. Louis encephalitis virus in horses ( with
mosquitoes
epizootic
his life-
Tabanidae. While
involved parasitology
agents transmitted
experimental
and
the
Academy
pursued
Society
60
in
scientific reports and
reviews,
abstracts.
he
of
a career that spanned
published well over
chapters,
California
participated
Pacific Coast Entomological
its President in 1974.
Neil
Associate
where
the
During
Besides the honors mentioned above, Neil also
the University of Nebraska ( 1952) and an Outstanding
Alumnus Achievement Award from the University of
Minnesota ( 1960).
Moreover, he was an honorary
Academy, he
a member of the
The latter constitute approxi-
received an Honorary Doctor of Science degree from
at the
Sciences, San Francisco,
names.
he promptly began his
Research
a
He and various
and
of
retirement,
Health, Education,
parasitology.
worldwide.
was presented a
Department
the
described no fewer than 550 new taxa of
matey 15 percent of the tabanid species recognized
shortly before his
Superior Service
and
as those to
coauthors
species- group
Mountain
Rocky
the
of
1962 to 1964,
in 1970, he
retirement
Award
director
as
impressive
Tabanidae representing 18 genus-group and 532
control of scrub
typhus fever in the southwest Pacific area.
Neil
There' s always something new under the
parasitological' sun ( the unique story of helminth-
him.
the
Robert S. Lane
with
Ley, Jr., Traub, and Lewthwaite
in
Department of Entomological Sciences
1948); establishing the etiologies of Australian tick
typhus ( 1950), Indian tick typhus ( 1952), and salmon
University of California
Berkeley, California 94720 USA
v
NUMBER 2
VOLUME
DECEMBER, 1987
12
October 9, 1987
Professor Jan Pinowski
Editor, International Studies on Sparrows
Polish Academy of Sciences
Institute of Ecology
05- 150 Dziekanow Lesny
POLAND
Dear Professor Pinowski:
I am responding to your request for a reprint of the article by Mitchell, Hayes, and Hughes entitled, " Relative
Abundance of Birds Along Transects in an Endemic Zone of Western Equine Encephalitis Vines Activity in
West Texas," published in 1984 in the Bulletin of the Society of Vector Ecologists 9( 1): 30-36. You will note
that this is essentially the same article that you published without our knowledge under the title, " The Relative
Abundance of Birds Along one Rural and Three Urban Transects in Hale County, Texas," in International
Studies on Sparrows 11: 34-36.
I submitted the manuscript to you initially. After retaining the manuscript for several months you wrote that
funds were no longer available to support publication of International Studies on Sparrows and you recommended that I submit the manuscript elsewhere. I did so and the paper was published in the Bulletin of the
Society of Vector Ecologists.
It was a surprise to subsequently receive a copy of your journal, which I thought was defunct, and to find the
same article printed there as well.
I would appreciate it if you would print a copy of this letter in the next issue of your journal. I also am sending
a copy to the Bulletin of the Society of Vector Ecologists for the same purpose.
Sincerely yours,
Carl J. Mitchell, Sc.D.
Chief, Vector Virology Laboratory
Centers for Disease Control
P. O. Box 2087
Fort Collins, CO 80522-2087 USA
CJM/bjb
Enclosures ( 2)
cc: Dr. James P. Webb
vi
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1987
BULL SOC. VECIUR ECOL, 12(2): 505-511
DECEMBER, 1987
LABORATORY FLIGHT ABILITY OF AEDES TRISERIATUS ( SAY)1
J. L. Clarke, III 2.3 and W. A. Rowley'
ABSTRACT:
The laboratory ( tethered) flight ability of 416 Aedes triseriatus mosquitoes was evaluated under
standard
conditions.
In the laboratory,1) Ae. triseriatus was found to be a strong flyer. Mosquitoes( 1 through 6 weeks
old) flew between 5,805
m ( week
and
9,910
m ( week
3).
The average distance flown by 60, 6-weeks-old
mosquitoes was 6,739 m. The length ( duration) of exhaustive flights increased as mosquitoes aged and there was
a correlation between how far mosquitoes flew and the length of their flights. Older mosquitoes were much slower
fliers; 6-weeks-old mosquitoes only half as fast as 5-weeks-old mosquitoes. Initial live weight did not have an effect
on flight ability. Up to 75 percent of a mosquito' s preflight( live) weight was lost during exhaustive flight. There
seemed totethered
be a threshold below which weight loss did not occur. Virgin, gravid, and parous mosquitoes exhibited
different
flight
abilities.
Uniparous and biparous mosquitoes did not fly as far as virgin or gravid
mosquitoes.
INTRODUCTION
Numerous studies have examined the dispersal of
Aedes triseriatus ( Say), particularly in relation to wood
lots. Dispersal flight by Ae. triseriatus of 50- 100 m or
from isolated wood lots into or across open terrain
have been reported in four separate studies in Wisconsin
more
DeFoliart and Lisitza 1980, Garry and DeFoliart 1975,
School et al. 1979, Mather and DeFoliart 1984). School
et al. (
1979) recovered
a marked
female
mosquito
in
studies have provided limited information on the
distribution of Ae. triseriatus within wood lots. Such
studies have contributed very little information on the
flight ability
released.
of
extensively in search
limited to wood lots.
suggested that
of oviposition
Beier
Ae. triseriatus
the size and structure
peripheral areas.
Berry
Tipis ( 1981)
and
also
Craig (
open
lot
as well as on
1984) found that
terrain
were
readily
by Ae. triseriatus. Although this species
seems to be somewhat reluctant to leave wood lots,
increasing evidence suggests that it does fly across open
colonized
terrain
under
some circumstances.
Oviposition
traps
and
vector mosquito.
This
to fly under controlled, laboratory
described by Rowley et al.( 1968) and interfaced with a
microcomputer ( Clarke et al. 1984).
MATERIALS AND METHODS
Mosquito Rearing Procedures.
Aedes
triseriatus
eggs from a 3- years- old
laboratory colony were hatched in deoxygenated water,
and larvae were reared in white enamel 25 x 41 x 7 cm
rearing trays ( 250 larvae
mixture of ground
not
strictly confined
of dispersal
may depend
of a wood
recently discarded tires in
is
was not
to the forest and that the extent
on
and
sites and
important
conditions using a flight-mill system similar to that
a
Sinsko and Craig ( 1979) found no
interchange between two wood lots
separated by 300 m of open terrain.
However, Nasci
1982) suggested that fence rows
connecting two wood
lots functioned as corridors for movement between
wood lots.
He indicated that Ae. triseriatus
flies
was
this
Ae. triseriatus
separate wood lot 425 m from the wood lot in which it
evidence
of
study examined the ability of virgin, gravid, and parous
per
tray). Larvae were fed a
Tetramin®
and dog biscuits.
Pupae were harvested on developmental day 10,
and females were separated from males on the basis of
size. Female pupae were divided into lots of 45 and
placed
in 0.5 1
paper cans.
Adult mosquitoes were
afforded access to cotton pads soaked in 0.3 M sucrose.
Both adult and immature mosquitoes were maintained
25. 6± 1° C
dark cycle.
at
and
75±
5 percent R.H. on a 16: 8 light/
Flight of Virgin Females.
A single carton of 45 virgin female mosquitoes was
mark- release- recapture
randomly selected for flight studies each day during a 6-
Journal
Paper J-12346 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa. Project
2277.
2Department of Entomology, Iowa State University, Ames, Iowa 50011, U.S A.
Present Address: Clarke Outdoor
Spraying
Co., P. O. Box 72288, Roselle, IL 60172, U.S. A.
from
flown to
in
m
their
by
each day
exhaustion
initial flights
fly
a
mosquitoes averaged
were
mosquitoes
inactivated
carton,
Mosquitoes that did not
weeks.
1, 600
this
and
weighted,
individual
Twelve
period.
weeks
removed
for
19,000
Nonfliers
from
the
were
were
mosquitoes
After
carton.
same
flight,
exhaustive
loss
to determine weight
reweighed
females flew an average of
flown
week
was
3 ( days 15- 19),
9, 910
the mean
One 3- weeks-old
m.
more than
9, 000
m.
A decline in flight ability
occurred in the fourth week. The mean distance flown
Flight
was 6,739 m, a decline of 32 percent from week 3. Flight
performance remained near this level through week 6.
24- hour
a
were
mos-
The duration of sustained, exhaustive flights
blood-fed
Twelve blood-fed
PE).
flown for
were
females
triseriatus
postemergence (
quitoes
on
Virgin Females.
Blood- fed
of
Unmated Ae.
day 5
period on
days 0-4
postfeeding ( days 5- 9 PE).
during week 1 was 268 minutes. By week 3, the
duration of sustained flights almost doubled to 478
minutes or
Flight
Six- days-old ( PE) females
being fed
held
were mated
were
placed
in 0. 5
induced
by
for 24 hours before
without sucrose
on a restrained rabbit.
mosquitoes
Individual
1
engorged
an
with
cartons
cup ( Mather and DeFoliart 1983) and a
balsa ovistrip( Novak and Peloquin 1981). After bloodoviposition
feeding,
were provided
mosquitoes
03 M
sucrose
in
On days 10- 12,
days PE), individual
initial blood
nonflown
mosquitoes was given a second
These biparous
mosquitoes were
initial blood
Analysis
log [ n
The correlation between how far mosquitoes flew and
their flight speeds was low, and there was a negative
correlation between the length of flights and the average
speeds of individual flights.
17- 19
The
blood
group
+
triseriatus
flown in
after
threshold below which weight loss does not occur.
After flight weights were remarkably similar, with most
27- 29 PE).
mosquitoes increased slightly as they aged. One-weekold mosquitoes weighed 4.06 mg, whereas, 6-weeks-
of variance was used
1]),
Ae.
live weights of mosquitoes and the amount of weight
loss during exhaustive flights. There seems to be a
similarly
flown for 24 hours on days 20-22
meal (
weight of
aged virgin
meal and allowed
and
average
these experiments was 4.6 mg. Figure 2 shows the mean
of parous
Analysis.
Statistical
data (
minute during the first 35 days of this study. During
week 6, mosquitoes flew only half as fast as in week 5.
porous and virgin mosquitoes were
flown for 24 hours. Another
to oviposit.
meal(
weeks
mosquitoes flew and the lengths of their flights.
Mosquitoes flew at speeds between 24 and 31 ni/
access
continuous
The length of flights
8 hours.
under
As
4 and 5.
during
expected, there was a correlation between how far
cotton pads.
after the
just
decreased considerably
Parous Females.
of
copulation and
the
In week 2( days 8-
mosquito flew 25,460 m and a second mosquito flew
22,212 m. During week 3, 50 percent of the mosquitoes
flew
flight
during
During
m.
distance
mosquitoes
other
with
replaced
36% flew less than 4,000
9,552.3 m. Forty-one percent flew more than 9,000 m
during this week, and 5 mosquitoes flew more than
of
rejected as non-
were
m(
m or more).
12 PE), Ae. triseriatus
six
minimum
5, 805
15% flew 9, 000
m, and
chilling,
fliers.
to
DECEMBER, 1987
BULL SOC VECTOR ECOL
506
old mosquitoes weighed
to test transformed
5. 15 mg.
The weight of an
individual mosquito did not affect how far it flew.
and correlation coefficients were
calculated to assess relationships between variables.
Priori
flight
comparisons were executed
performance
between
Flight of Parous Female Mosquitoes.
to test differences in
Statistically significant differences occurred in the
weeks.
distance flown and duration of flight of virgin, parous,
and biparous mosquitoes. Parous mosquitoes were 1719 days old( PE), and biparous mosquitoes were 27-29
RESULTS
Flight
of
Statistically
occurred
speed of
days
Virgin Female Mosquitoes.
significant
differences ( P <
in the distance flown, the duration,
flight
to another.
of virgin
Ae.
triseriatus
However, differences
from
and the
for
any of the flight parameters between days
Figure 1 shows the mean distance flown weekly by 40
A total of 416 mosquitoes was flown
mosquitoes.
within weeks.
during
1, 600
this study, of
which
264 ( 63%) flew
m and were treated as
fliers.
more than
During
week
1,
PE)( TABLE 1).
Virgin mosquitoes averaged
study, virgin females flew 55.7 percent farther than
one week
were not evident
old(
11, 717 m. Uniparous and biparous mosquitoes flew an
average of 7,734 m and 7,355 m, respectively. In this
0. 001)
parous
(
905
mosquitoes.
minutes)
mosquitoes (
599
Virgin females also flew longer
than either uniparous or biparous
and
563
minutes,
respectively).
The
mean number of eggs laid by uniparous mosquitoes
was
90.
eggs.
Biparous mosquitoes laid an average of 72
DECEMBER, 1987
BULL SOC. VECTOR ECOL
DISCUSSION
Generally,
Ae. triseriatus
extremely limited flier,
is
extent of its flight ability. Aedes triseriatus flew well
considered to
less
more or
507
be
an
restricted to wood
lots( its
natural habitat). These studies indicate that Ae.
triseriatus is a strong flier capable of
flying much farther
than the 50 to 100 m
generally considered to be the
for the entire 6 weeks tested; however, there was a
characteristic decline in flight ability beginning in the
fourth week. A similar decline has been observed in
other species of mosquitoes.
Age-related changes in
flight performance of virgin mosquitoes have been
reported
by Rowley
and
Graham ( 1968),
Rowley
10000 -
r:
isi
8000 -
0.}
1
6000 5
ki
1:1
o
E>
4000
of
bi
g
l
2000
s:::z
h
V#
i
Y
0
1
2
3
4
5
6
Age (Weeks)
Figure 1.
Mean
distances flown by virgin female Aedes triseriatus mosquitoes. Sixty mosquitoes were flown
each week for
6
weeks.
1970),
Nayar
and
Sauerman (
and
Maximal flight
performance
Culex
Coquillett
tarsalis
in Aedes
occurred
during
decrease in flight ability, but it did not occur until the
1973).
1972,
aegypti (
the
L.)
and
first 14
life ( Rowley and Graham 1968, Rowley
Three- weeks- old Cx. tarsalis and Ae. aegypti
flew only about 60 percent as far as younger( 1- 2 weekshad a similar
Aedes triseriatus
old) mosquitoes.
days
DECEMBER, 1987
508
of adult
1970).
6
•
fourth week of adult life.
Rowley ( 1970) found that gravid Cx. tarsalis
mosquitoes flew substantially farther than virgins, but
did not find an age-related loss of flight ability in gravid
For
mosquitoes.
some reason,
the
physiological
changes that occur during the gonotrophic cycle allow
Preflight Wt.
V.
Weight Lost
5-
F•
P-
e
is
a.
X
4
t'
s
r
iR
t;
r
o
Alr.„
r..
V ...!'„
k
eN
s:
4,•
,.,.',.-
i'i
0
1
2
3
4
5
6
Age ( Weeks)
Figure 2.
Weekly preflight weights and weight lost during exhaustive flight by virgin female Aedes
triseriatus
mosquitoes.
DECEMBER, 1987
Cx. tarsalis to
Lea( 1975)
cycle
are
maintain
and
in
changes
BULL SOC. VECIUR ECOL
Klowden
mosquito
under
its ability to fly long distances.
and Lea( 1979) concluded that
activity
endocrine
during
control
the gonotrophic
by
mediated
the
Jones and
neurosectretory system and the ovaries.
Gubbins ( 1978), Jones ( 1981), and Clarke and
Rowley
unpublished data) all found increased levels of
spontaneous flight activity in gravid mosquitoes. Beier
et al. (
1982) did
fmd
not
a correlation
between the
distribution of eggs collected from ovitraps and the
horizontal resting distribution of marked or natural
populations
of
Ae. triseriatus
oviposition
resources
search
some
1981)
Ae. triseriatus. They suggested that
flies out of resting areas in search of
to
sites
ensure
throughout
for
dispersal
of
out
forest.
the
oviposition
sites
Undoubtedly,
would
wood
Nasci ( 1982)
and
lots.
does
not
undergo
appetential stimulus
combined
represents
a
and
mechanism
encephalitis cases
lots
considered
lids cases examined from 1979 to 1981 were associated
tires ( Craig 1983). Fourteen isolates of LAC
virus were obtained from 4,903 Ae. triseriatus larvae
taken from a discarded tire in the back yard of a sick
with old
home( Craig 1983). Leiser( 1981) demonstrated
the magnitude of the urban distribution of Ae. triseriatus
child' s
when she
found that 34
of
48
sections (
66%) of South
Bend, Indiana had positive ovitraps.
The flight ability of this species, particularly in
the literature suggests. The ability of Ae. triseriatus to
fly significant distances probably plays a role in the
in
that Ae.
the
epidemiology of LAC virus and is significant in the
ability of Ae. triseriatus to colonize discarded tires in
gravid
both rural and urban environments. The natural flight
probably
for this
range of this mosquito needs to be evaluated along with
the influence that infection with LAC virus has on its
flight ability.
disperse is
These studies have demonstrated that Ae.
triseriatus has the ability to fly substantial distances
to
to
a
these areas are well removed
triseriatus.
DeFoliart 1984). In a retrospective study
in Ohio, approximately half of the 71 LAC encephaand
majority of La Crosse ( LAC)
occur in urban or rural environments.
of
important because
Often
Ae. triseriatus
near human habitation ( DeFoliart and Lisitza 1980,
Mather
Trpis
mosquito.
The ability
wood lots, and transovarial transmission of LAC virus
to progeny provides an immediate focus of infection
urban environments, may be substantially greater than
flights,
sites,
tires, are colonized by Ae. triseriatus emigrating from
in
variation
being
with
this
result
Assuming
oviposition
dispersal
primary
Beier
migratory
associated
limited
with
also
that
suggest
habitat may influence dispersal.
triseriatus
hole
efficient use of tree
509
be
Man- made
the
natural
containers,
from large
habitat
wood
of
Ae.
especially discarded
and for considerable lengths of time. It is not known
if such flights occur under natural conditions; and
if they do, what factors or conditions mediate such
flights.
Additional studies, especially in the field,
TABLE 1. Mean distance( m), duration( min), and speed( m/min) flown by gravid, virgin, uniparous,
and biparous Aedes triseriatus mosquitoes in a 24- hour period.
Pari ty
N
Gravid'
60
10780
(
442)
763
(
36)
14
(
0. 5)
Uniparous
15
7734
(
789)
599
(
93)
13
(
1. 4)
Biparous
12
7355 (
1258)
563
(
112)
13
(
1. 0)
Virgins
27
773)
905
61)
13
(
0. 8)
Distance ( SEM)'
11717
(
Duration ( SEM)
(
Speed( SEM)
Standard emir of the mean.
Gravid mosquitoes were 0-4 days old ( post-blood meal) and 5- 9 days old ( postemergence).
Virgin mosquitoes represent two groups 15- 17 days old flown as controls with the uniparous
mosquitoes and
20-22 days
old
flown
with
the
biparous
mosquitoes.
and
DECEMBER, 1987
510
designed to determine how this
needed
are
environments,
urban
to
species
flies in
inhibition of host-seeking in Aedes aegypti during
evaluate
the role
oocyte maturation. J. Insect Physiol. 25: 231- 235.
of Ae, triseriatus as an urban vector of LAC virus.
Lea, A. 0. 1975. The control of reproduction by a blood
CITED
REFERENCES
the mosquito or a model for vector
meal:
Acta Trop. 32: 112-115.
endocrinology.
Beier, J. C. and M. Trpis. 1981. Local distribution of
Aedes
triseriatus
Beier, J. C., W. J.
Culicidae)
Diptera
(
Berry,
the
at
G. B.
and
Craig,
Aedes
adult
of
blood source on the gonotropic cycle of Aedes
structure,
oviposition, and other
mosquito species.
J. Med.
to
Craig, Jr. 1984. Bionomics
breeding in scrap tires
Mosq. News 44: 476-484.
atropalpus
northern
Indiana.
triseriatus.
Am.
J.
Trop. Med. Hyg. 32: 189-
193.
Entomol. 19: 239- 247.
Aeries
Comparison of two survey
Mather, T. N. and G. R. DeFoliart. 1983. Effect of host
habitat
G. B.
area:
1982.
r.
relation
and
urban
triseriatus
Diptera: Culicidae) in
J.
an
methods. Proc. Indiana Acad. Sci. 90: 248-253.
Horizontal distribution
Berry, W.
Leiser, L. 1981. Distribution of Aedes triseriatus ( Say)
in
News 41: 447-455.
Mosq.
Baltimore Zoo.
of
in
Mather, T. N. and G. R. DeFoliart. 1984. Dispersion of
gravid Aedes triseriatus ( Diptera Culicidae) from
wood lots into open terrain. J. Med. Entomol. 4:
384- 391.
Clarke, J. L., III, W. A. Rowley, S. Christiansen, and D.
monitoring
mosquito
Microcomputer- based
1984.
W. Jacobson.
and
flight
data
mill.
acquisition
system
for
a
Ann. Entomol. Soc. Am. 77:
Nasci, R. S. 1982. Activity of gravid Aedes triseriatus
in wooded fence rows. Mosq. News 42: 408412.
119- 122.
Nayar, J. K.
Aedes triseriatus:
G. B., Jr. 1983. Biology
Some factors affecting control. Pp. 329- 241 In
California Serogroup Viruses ( C. H. Calisher and
of
Craig,
W. H. Thompson,
and
D. M. Sauerman, Jr.
1972.
Flight
performance and fuel utilization as a function of
in female Aedes
Entomol. 7: 27- 35.
age
taeniorhynchus.
J. Israel
Alan R. Liss, Inc., New
eds.).
Nayar, J. K.
York, NY, 399 pp.
and
D. M. Sauerman, Jr.
1973.
A
comparative study of flight performance and fuel
DeFoliart, G. R.
and
M. A. Lisitza.
Aedes triseriatus in
open
1980.
terrain.
Activity by
Mosq. News 40:
utilization as a function of age in females of Florida
mosquitoes. J. Insect Physiol. 19: 1977- 1988.
650- 652.
Novak, R. J.
Gary
C. E.
and
G. R. DeFoliart. 1975. The
basal treehole
triseriatus (
closure
on
suppression
Diptera Culicidae).
Mosq.
effect of
of
Aedes
News 35:
and
J. J. Peloquin.
1981.
A substrate
modification for the oviposition trap used for
detecting the presence of Aedes triseriatus. Mosq.
News 41: 180- 181.
289- 297.
Jones, M. D. R.
1981.
flight activity
in
The programming
relation
to
of circadian
mating
and
the
Rowley, W. A. 1970. Laboratory flight ability of the
mosquito, Culex tarsalis Coq. J. Med. Entomol. 7:
713- 716.
gonotropic cycle in the mosquito, Aedes aegypti.
Rowley, W. A. and C. L. Graham. 1968. The effect of
Physiol. Entomol. 6: 307- 313.
S. J. Gubbins. 1978. Changes in the
age on the flight performance of female Aedes
aegypti mosquitoes. J. Insect Physiol. 4: 719-729.
circadian flight activity of the mosquito Anopheles
in relation to insemination, feeding and
gambiae
Rowley, W. A., C. L. Graham, and R. E. Williams.
Jones, M. D. R. and
oviposition.
Physiol. Entomol. 3: 213- 220.
1968. A flight mill system for the laboratory study
of mosquito flight. Ann. Entomol. Soc. Am. 61:
Klowden, M. J.
and
A. 0. Lea.
1979.
Humoral
1507- 1514.
i
DECEMBER, 1987
Scholl, P. J., C. H. Porter, and G. R. DeFoliart. 1979.
Aedes triseriatus:
persistence of nulliparous
females under field
368- 371.
conditions.
Mosq.
News 39:
511
Sinsko, M. J. and G. B. Craig, Jr. 1979. Dynamics of
an isolated population of Aedes triseriatus
Diptera: Culicidae).
Entomol.
15: 89- 98.
1. Population size. J. Med.
DECEMBER, 1987
512-516
BULL SOC. VECtOR ECOL, 12( 2 ):
THE Ell-,ECT OF IMMATURE MOSQUITOES ON OVIPOSITION BY
AND CULISETA INCIDENS
CULEX PIPIENS QUINQUEFASCIATUS
DIPTERA: CULICIDAE) IN THE NIELD1
T. R. Wilmot2'3, S. E. Cope2, and A. R. Bang
ABSTRACT: A study was conducted of oviposition preferences of Culex pipiens quinquefasciatus Say and Culiseta
incidens (
Thomson) females among field containers with immature Cx. p. quinquefasciatus, Cs. incidens, both
species together, or with no immatures. Females of both species oviposited preferentially in containers with conspecific immatures but other unidentified factors seem to be equally or more important in oviposition site selection.
INTRODUCTION
Marks by Gubler( 1971) and Aedes sierrensis ( Ludlow)
by
All
less
mosquito species
restricted,
habitat in
have
likely
adult
mosquitoes
distribution
factors possibly affecting
species of oviposition
develop.
for
responsible
Physical
the
and
of
attraction
have been the
sites
this
chemical
the influence of immature mosquitoes on oviposition in
mosquito
the field is not known. The present paper reports the
effects of the presence of immatures on oviposition of
subject of
investigations.
numerous
Pheromones
Oviposition
triseriatus by Bentley et al. ( 1976).
With very few exceptions, these experiments were
conducted under controlled laboratory conditions and
most
are
MacClelland ( 1983).
It
larvae
their
which
immatures.
of
and
attraction could not be shown for eggs of Aedes
that specific ovipositional preferences of
seems
Ahmandi
a characteristic, more or
Culex
or other chemicals associated with
the
pipiens
quinquefasciatus
Say and Culiseta
incidens ( Thomson) in the field.
presence of immature mosquitoes may possibly
influence
The
oviposition.
of
presence
METHODS AND MATERIALS
attractive
substances has been associated with larvae of Culex
Ikeshoji( 1966), Aedes
pipiens
by
Soman
and
Aedes
1973)
atropalpus
and
Bentley
Coquillett)
(
et al.(
1976)
Liston
Reisen
by
communis
were attracted
by
McDaniel
and
showed that
and
et al. (
Brust
and
and
Hsi ( 1977),
and
communis.
shown with
Brust( 1973), Ae.
Culex
Ae.
aegypti
salinarius
Aedes
females
Pupae
may
attractants
Larval rearing
attraction to Aedes
water
was
not
by
avocado tree
branches.
Mosquito larvae
used in all experiments were from eggs collected at the
site.
Samples of larvae from several egg rafts
were reared in the laboratory to confirm identifications;
study
all were Cx. p. quinquefasciatus or Cs. incidens and
separation of the two species was completely reliable.
universal.
unsuccessfully tested for
and Aedes polynesiensis
albopictus
protected
Roberts
by
Coquillett by
be
containers were maintained in locations shaded and
atropalpus
Andreadis ( 1977).
Oviposition
Ovitrap con-
34 x 34 x 15 cm and consisted of a sheet of plastic
The
supported by 4 interlocking wooden side pieces.
stephensi
communis
Ae.
California, Los Angeles.
1976), Culex
to factors associated with larvae of Ae.
those of
of
Say by
Langis( 1985). Maire
Ae.
University
tainers were constructed that measured approximately
triseriatus
Siddiqui ( 1978),
Maire
Experiments were conducted in an abandoned and
undisturbed experimental orchard on the campus of the
Anopheles
and
factors have been
Kalpage
and
by
as well as
atropalpus
associated
and
DeGeer
Langis( 1985)
and
and
Giles
and
Kalpage
by
Maire( 1984, 1985), Aedes
tritaeniorhynchus
by
Hsi( 1977),
Linnaeus
aegypti
Rueben( 1970) and Roberts
Nine containers were set at the study site on 13 July
1982 and filled with tap water to which dry dog food and
rabbit chow was added. On 14 July, 50 to 1000 newly
hatched larvae ( Cs. incidens, Cx. p. quinquefasciatus ,
or both species together) were added to eight containers;
This work was supported by Research Grant No. USPHS AI-11847 from the National Institutes of Health, Bethesda,
Maryland.
2School of Public Health, University of California, Los Angeles, California 90024, U.S. A.
3Present
address:
Midland
County
Mosquito Control, 2957 Venture Drive, Midland, Michigan 48640-8906, U.S A.
DECEMBER, 1987
had
one container
were
random numbers.
pupae
were
daily. Tap
various
Larvae
removed
rafts
populations of
the
and
( TABLE 1).
using
and
species than in those with Cx. p. quinquefasciatus only
removed
or
to maintain the
daily until all larvae had
died ( 3 August).
The experiment was
repeated from 4 August to 26 September and again from
27 September to 9 November. Between trials the concontainers were examined
pupated
to
second
be
added were again assigned
and
respectively,
third
12
trials
were used and
only
and
randomly. hi
14
the
rabbit chow was added
Analysis of variance ( TABLES 3 and 4) suggests
that oviposition by both species is influenced by
immature
mosquitoes
containers.
Analysis of
variance and graph of the numbers of egg rafts per week
(
Figure 1) suggest, however, that other factors also
oviposition.
The reduction in egg rafts
collected after three or four weeks suggests a change in
1979), succession of algal species or deterioration of
pheromones.
in
in the
attractancy with time. Factors possibly associated with
this change include age of infusion ( Kramer and Mulla
RESULTS
collected
The attractancy of
influence
containers,
to each container.
Most Cx. p.
larvae ( TABLE 2).
with 50 or 500 larvae.
or
tainers were cleaned and refilled and the numbers of
larvae
no
crowding of larvae. Containers to which 1000 larvae
were added collected fewer egg rafts than containers
matter was added
The
with
breeding water to females was possibly reduced by
approximately 12 cm, but no organic
by the investigators after the first day.
at
In two of three trials most Cs. incidens egg
rafts were collected in containers with only conspecific
larvae and more were collected in containers with both
before
containers
identified
were
larvae
develop
were allowed to
from
by
containers
water was added as needed
level
water
the
Egg
emergence.
larvae. The
no
to
assigned
513
quinquefasciatus
containers
with
only
egg
rafts
conspecific
The decline in numbers of egg rafts
were
collected after the first trial could have been due to an
larvae
actual decline in the number of ovipositing females in
TABLE 1. Number
of Culex pipiens quinquefasciatus egg rafts collected from field containers during three
trials.
Number of larvae added to container
Cs. 50
500
1000
0
0
0
50
450
50
950
Trial
Cx. 0
0
0
50
500
1000
450
50
950
50
I
138
119
81
127
129
121
162
132
II
59
66
40
103
127
71
61
49
53
53
68
89
III
66
34
10
79
71
66
77
48
58
23
50
42
68
32
263
219
131
309
327
258
300
229
111
76
195
131
68
32 2649
Total
-
-
0
0
0
0
77
-
-
0
0
0
0 Total
-
-
1086
-
839
724
TABLE 2. Number of Culiseta incidens egg rafts collected from field containers during three trials.
Number of larvae added to container
Cs. 50
Trial
Cx.
500
1000
0
0
0
50
450
50
950
0
0
0
0
0
0
0
50
500
1000
450
50
950
50
0
0
0
0 Total
-
I
43
48
25
29
22
16
19
39
II
16
20
18
19
37
27
24
17
18
19
15
25
III
16
15
4
10
4
5
6
5
13
5
10
1
9
7
110
75
83
47
58
63
48
49
61
31
24
52
26
9
7
633
Total
-
27
-
-
-
-
268
-
255
DECEMBER, 1987
514
Analysisl of Culex pipiens quinquefasciatus oviposition.
TABLE 3.
P
F
MS
SS
DF
Source
2
23354. 51
11677. 26
122. 81
0.01
Week
7
9295. 94
1327. 99
13. 97
0.01
Mosquito
3
846. 14
282. 05
2.97
0.05
Error
194
18446.48
95.09
Total
206
51943.47
MS
F
P
1181. 97
96.41
0.01
Trial
1General linear models procedure.
Analysisl of Culiseta incidens oviposition.
TABLE 4.
SS
DF
Source
2363. 93
2
Trial
Week
7
382.65
54. 66
4.46
0.01
Mosquito
3
198. 38
66. 13
5. 39
0.01
Error
194
2378.51
12.26
Total
206
5323.48
1General linear models procedure.
the area
to
or
in the attractancy
change
a
Populations
containers.
of
Culiseta
Traps
the
of
California typically are greater in cooler months( Miura
et al. 1976); a decline in number of Cs. incidens in the
fall is
matter
bably
larvae
The
unexpected.
added
to the
contributed
the greater
containers
number
of
been
egg
of
pro-
development
responsible
rafts collected
in
part
during
of
for
that
trial,
DISCUSSION
A
clear
oviposition
understanding of the factors influencing the
behavior of mosquitoes has not yet been
(
of a program
to control Ae. triseriatus and
LaCrosse encephalitis in LaCrosse County, Wisconsin
Measures of oviposition am under
Parry 1983).
investigation as a means of monitoring populations of
several
mosquito
species.
factors
Further investigations of
oviposition
and
influencing
their relative importance in the field may lead to an
increased use of female or egg collections in the study
Further underof mosquito biology
and
control.
the
mosquito
standing of the effect of immature mosquitoes on oviposition may benefit the development of models of
mosquito population dynamics.
Conspecific immatures may attract gravid
developed.
females but
part
organic
in the first trial
to the more rapid
may have
and
amount
greater
for the collection of gravid Culex
mosquitoes are now used in arbovirus surveillance
programs ( Reiter et al. 1986) and ovitraps are used as
in
species
other unidentified
factors,
which
Acknowledgements
influence
the quality of the environment for larval development,
may be equally or more important in
selection in the field.
Large numbers
render a site
less
attractive to
females.
site
We thank Dr. Charles Taylor, Department of
larvae may
Biology, University of California, Los Angeles, for his
oviposition
of
helpful
comments.
DECEMBER, 1987
515
480 —
a
l;.I.
I.
120
_
100
Culex
360 —
Culiseta
r
80
x
240 —
120 —
ei
60
•
I
I
I
I
40
20
I
I
I
1
2
3
an
cn
ao
ao
ao
aA
W
w
c
240—
1
V
O
40
V
p
120—
L
ti
Z
I
I
I
1
2
3
I
4
I
I
I
I
5
6
7
8
20
N
0
Z
240—
C
N
40
120—
e4•
20
0
I
1
I
2
I
I
I
I
3
4
5
6
0
Collection Week
Figure 1.
totals of egg rafts collected in field containers
during three trials. ( a)
August, ( b) 4 August to 26 September, and ( c) 27 September to 9 November.
Weekly
13 July to 3
DECEMBER, 1987
516
Make, A. and R. Langis. 1985. Oviposition responses
CITED
REFERENCES
of
Ahmandi, A.
and
Oviposition
mosquito,
1983.
G. A. H. MacClelland.
the
of
attractant
Aedes
tree hole
western
Aedes ( Ochlerotatus)
Culicidae)
to
Diptera:
J. Med.
111- 112.
Entomol. 22( 1):
An
1977.
in Culex
origin
ovipositional attractant of
Mosq.
salinarius.
News
Effects of color and larval
1976.
Yatagai.
produced attractants on oviposition by Aedes
triseriatus.
Env. Entomol. 5( 3): 553- 556.
53- 56.
Miura, T., J. W. Kleiwer,
Bentley,
(
water.
McDaniel, I. N., M. D. Bentley, H. P. Lee, and M.
Andreadis, T. G.
37( 1):
communis
holding
Mosq. News 43(3):
sierrensis.
343- 345.
pupal
larval
M. D., I. N. McDaniel, H. P. Lee, B. Stiehl,
triseriatus
Aedes
and
Aedes
of
atropalpus
Gubler, D. G.
Studies
1971.
behavior
of
Aedes
albopictus
Seasonal
and
of
occurrence
foothills
of
Fresno
1976.
C. H. Tempelis.
Culiseta incidens
County, California.
in
Mosq.
News 36( 3): 343- 349.
Diptera:
the comparative ovi-
on
Aedes
(
112- 115.
J. Med. Entomol. 13( 1):
Culicidae).
triseriatus
by
produced
attractants
oviposition
position
Studies
1976.
M. Yatagai.
and
and
Aedes
Parry, J. E. 1983. Control of Aedes triseriatus in
LaCrosse, Wisconsin. Pp. 355-363, In California
Serogroup Viruses. ( C. H. Calisher and W. H.
Thompson, eds.).
Alan R. Liss, Inc., New York.
polynesiensis. J. Med. Entomol. 8( 6): 675-682.
Ikeshoji, T. 1966. Studies
the choice
fatigans
Chemical factors
Part I.
stimulants.
of
on mosquito attractants and
oviposition
and pallens.
Japan
determining
by Culex pipiens
J. Exp. Med. 36( 1): 49site
Reisen, W. K. and T. F. Siddiqui. 1978. The influence
of conspecific immatures on the oviposition
preferences of the mosquitoes Anopheles stephensi
Pakistan J. Zool.
and Culex tritaeniorhynchus.
10( 1):
31- 41.
59.
Kalpage, K. S. P.
and
R. A. Brust
attractant produced
1973.
by immature Aedes
Oviposition
Reiter, P., W. L.Jakob, D. B. Francy, and J. B. Mullenix.
1986. Evaluation of the CDC gravid trap for the
atropalpus.
surveillance of St Louis Encephalitis vectors in
Memphis, Tennessee. J. Am. Mosq. Cont Assoc.
Env. Entomol. 2(4): 729-730.
2(2): 209-211.
Kramer, W. L.
and
attractants
of
Culex
of
Oviposition
mosquitoes:
mosquitoes
to
infusions. Env. Entomol. 8( 6): 1111- 1117.
Maim, D. J.
responses
1984.
of
Maire, D. J.
oviposition
1985.
atropalpus
Mosq.
Effect
to experimental
News 44( 3): 325- 329.
of axenic
site selection of
Mosq. Cont.
Roberts, D. R.
and
B. P. Hsi.
1977.
A method for
evaluating ovipositional attractants for Aedes
Diptera Culicidae) with preliminary
aegypti
(
results.
J. Med. EntomoL 14( 1): 129- 131.
An analysis of the oviposition
Aedes
oviposition waters.
Am.
1979.
repellents
responses
oviposition
organic
M. S. Mulla.
and
Aedes
larvae
on
atropalpus.
Assoc. 1( 3): 320-323.
the
J.
Soman, R. S.
and
R. Rueben.
1970.
Studies on the
preference shown by ovipositing females of
Aedes aegypti for water containing immatures of
the
489.
same
species.
J. Med. Entomol. 7(4): 485-
BULL SOC. VECTOR ECOL, 12(2): 517- 527
DECEMBER, 1987
PA'FIERN OF THELYTOKY ACQUISITION IN MUSCIDIFURAX RAPTOR
GIRAULT AND SANDERS ( HYMENOPTERA: PTEROMALIDAE)
E. F. Legnerl
ABSTRACT: The manner in which uniparental ( thelytokous) reproduction is incorporated in a hybrid biparental
arrhenotokous) population of Muscidifurax raptor Girault and Sanders after mating with males of thelytokous
Muscidifurax uniraptor Kogan and Legner implicates extranuclear factors; e.g., microorganisms and chemical
substances. Genetic change may not be involved in the acquisition of thelytoky.
INTRODUCTION
subsequently produced thelytokous F offspring
Legner
Increasing
of
is focused
attention
hymenopterous
parasitoids
in the
1987a).
The present study details the
reproductive changes observed during the acquisition
importance
the
on
phase of thelytokous reproduction.
natural control of
synanthropic flies as costs and hazards of chemical
control
mount (
Morgan
Mullens
1981,
1986,
al.
et
Petersen and Meyer 1983, Rutz and Axtell 1979). When
introducing
is
theoretically
local
with
dilution
of
To study the pattern of acquisition of thelytokous
parasitoid strains with attributes that afford
a greater potential
for
fly
control(
to
advantageous
in
populations
desired
Legner
order
characteristics.
1982), it
reproduction, separate cohorts each of 10- 18 3-day-old
outbreeding
females of M. uniraptor from Cayey, Puerto Rico, and
to slow the loss or
Israel and Utah strains of M. raptor were isolated in
et al.
reduce
The
screened polystyrene vials ( 46 cm'),
adoption of a
such
that
genes
desired
the
confer
outbreeding is reduced or eliminated.
A thelytokous species, Muscidifurax
Kogan
and
to produce
Legner, from
naturally
in its
early
whereas,
Cayey, Puerto
unusually high
an
reproductive
induce
offspring ( Legner 1985b).
role of such
males remains obscure,
in the
and
thelytoky
the
former
occupies
of
M.
uniraptor
Sanders, especially as
intermediate position
taxonomically ( Kogan and Legner 1970) and
alleleomorphically ( Kawooya 1983) in the genus.
Thelytoky
uniraptor
by
was
then
males to
crossing
transferred
hybrid females
that
strains
geographically distant
areas (
transfer process, a change
observed
by
Department
of
the
in
mated
mm
X 2.8±
0.2 mm), distributed randomly
commercial CSMA® medium.
at
Host puparia were exposed to parasitoids for 24- h
25. 5± 1° C, 55% RH, and a 13L: 11D photoperiod of
ca. 269 lux irradiance at table level. Light was supplied
and
an
day old males
by fluorescent lamps. Parasitization efficiency at this
host density and in this environment was near optimum
for testing whether
inherited in arrhenotokous
Girault
to <_1-
LeBaron)
produced males
raptor
day
known to be functional
mytilaspidis (
candidates
be
could
6.4 ± 0. 5
male
DeBach 1972).
These naturally
seemed like ideal
Muscidifurax
are
Aphytis
thelytokous
Rossler
they
Although the
one
Each female was supplied daily
over the vial base. Flies were reared to pupation using
high
to
ova
for
mated
with 20, 24 to 30-h-old puparia of Musca domestica L.
(
1985a),
temperatures previously was required to
were
secured at random.
Rico, was found
number of males
developing
the
of
exposure
They
uniraptor
Legner
period (
each captured in the wild had been maintained for only
2-3 generations to minimize inbreeding ( Legner 1979).
because
traits
with a basal area
of 7 cmz Cultures which originated from> 100 females
completely parthenogenetic ( thelytokous) reproductive
mode in the preferred strain may minimize the loss of
mating the M.
M. raptor created
by
of
were
secured
Legner 1987a).
reproductive
behavior
hybrid females
Entomology, University
from
In the
of
(
Legner 1967,
1979).
Puparia were then incubated
separately in gelatin capsules ( 10 X 25 mm) for the
emergence of F, parasitoid and host progeny.
Unemerged puparia were dissected to detect aborted
parasitism.
Parasitoid longevity, male and female progeny,
and host destruction were recorded for each female
through the age of 16 days, which is about half the life
expectancy in the described environment ( Legner
1987a, Legner and Gerling 1967). The importance of
extended experimental time for viewing behavior accu-
was
rately is becoming recognized for parasitoids ( Hey and
which
Gargiulo 1985) and Drosophila spp. (Templeton 1982).
California, Riverside, CA
92521
U.S A.
DECEMBER,
518
Modified
laboratory
studies
involving
statistics
potential
reproductive
parasitoids were
for
derived
R0)
intrinsic
and
The statistic mx
calculation.
measured the " effective" number of female offspring
per female in the age interval x( 24-h), as only emerged
as
These
discussed previously ( Legner 1985a, 1987a).
included derivations of the Birch( 1948) formula for the
net reproductive rate (
1,.
to begin the
used
1987
offspring
This arrangement permitted
were counted.
comparisons
rate of natural
of adult parasitoid behavior, and
and
increase ( rm); the net parasitization rate (
intrinsic rate of parasitization( r„); the net total fecundity
Rp)
eliminated slight strainal differences inherent among
fecundity
puparia revealed < 2 percent aborted parasitism, which
rate( males+
females) ( Ri)
rate( r,); and net
and
intrinsic
host destruction
rate(
total
Rd)
and
developmental
Dissections
stages.
of unemerged
gave credibility to adult parasitoid emergence data.
intrinsic
Experiments
were
conducted
with
replicates
Such statistics enable
host destruction ( rd).
comparisons of the direct effects of mating on female
arranged in a completely random split plot design in
parasitoids.
space.
rate
of
In
deriving
these values, the pivotal age, or time
development from the egg to adult emergence, was
estimated as the mean length of development of females
Analyses of variance were performed on the
binomial data transformed to
for
iX+
1/ 2, and significant
differences tested with Duncan' s multiple range tests
(
Duncan 1955, Steel and Torrie 1960).
25.5± 1° C, 55% RH. Females, which were three days
old( post eclosion) when an exposure began, had a mean
at
pivotal
age of
survival rate of
RESULTS AND DISCUSSION
An estimated 90 percent
24. 5 days.
immature females from
The pairing of( Israel females X Utah males) M.
oviposition was
Female progeny, total progeny, and host destruction by P, and hybrid populations of
TABLE 1.
Muscidifurax raptor and Muscidifurax uniraptor, where oviposition is continuous at 25.5 ±
1° C.
and
55%
RH on 20 Musca domestica puparia daily for 14 days.1
Avg.
Females
Population
Puerto Rico Females -
26.0•
virgin
No./(
Avg. Host
s)
Total
Progeny
199.
9. 4)
3. 4)
Israel Females -
842'
mated
124. 0'
19. 1)
10. 7)
Utah Females -
169. 4d
mated
204.
w/
78.
Utah Males
01'
94. 5d
17. 7)
18. 6)
121. 5'
Israel Females X Utah Males)Females
w/
Israel Females X Utah Males)Females
X Puerto Rico Males] Females Mean
squared error ( 66
d02
204. 2ab
5. 1)
2. 1)
Puerto Rico Males
virgin
39. 0'
1a6
9. 8)
8. 5)
Israel Females
7ab
219. 0'
4. 8)
7. 9)
2.999
3. 537
Destruction/( s-)
18. 0•
0.43)
13. 4b
0.67)
17. 2'
0.47)
9.8'
1. 21)
17. 0'
0. 50)
18. 7"
0.32)
0. 154
Values followed by the same letter are not significantly different( P<_0.05; Duncan' s [ 1955] multiple range
test); analyses performed on transformed expressions of single females(
On
transformed scale.
X + 1/ 2).
DECEMBER,
1987
519
with Puerto Rican M. uniraptor
female progeny in every replicate. All
these progeny reproduced by thelytoky because
population through 25 generations as of this writing.
mating was not required for the subsequent production
of female offspring.
Thelytoky was retained by this
not yield female progeny, and thus were judged
raptor
female hybrids
Matings of male M. uniraptor with female hybrids from
males produced
of
the reciprocal cross ( Utah females X Israel males) did
unsuccessful.
Muscidifurax uniraptor
PUERTO RICO 1981-
P- I Virgin)
TOTAL
HOSTS
KILLED
20 -
cr,..
16 O
Z
O'•-
ii.,
0'
v'
••
.'
0-
/
W
o--- 4. rd' 01911•
\
0.•
0..
r
TOTAL
Rd= 226.66
t
t
•••-
_
o-•.,`
t
0
PROGENY
s
r—
Rt= 179. 69
rt =0.1833
8-
4-
1
0
1
1
1
1
1
1
1
1
1
1
1
1
1
100
lx
2
20
r
Z
W
0
C7
R0. 23. 40
rm= 0. 1291
11
dd
16
a:
0. 75 Z
1'
a•
0. 50
Z12
Z
C.6
0
i
H
8
Q
a:
0.25
inx
0
aO
tx
a_
i
0
0
3
4
5
6
7
8
9
AGE OF ADULT
Figure 1.
Survival
tx),
and
rate (
1X),
and
domestica
uniraptor,
puparia per
II
12
13
14
15
16
FEMALE ( days)
daily fecundity ( m) (= female progeny), male progeny, total progeny
host destruction ( d,)
Muscidifurax
10
for 10 virgin females of the Cayey, Puerto Rico strain of
ovipositing continuously
day.
at
25.5±
1° C.
and
55% RI-I. on 20 Musca
DECEMBER, 1987
520
A distinctive
during
evident
Utah isolates, respectively. The fecundity of the Israel
Israel females X
strain in the presence of Utah males is shown in Figure
4, and the( Israel females X Utah males) hybrid females
pattern
reproductive
to the(
the transfer of
was
thelytoky
female hybrid as diagrammed in Figures 16. Original parental fecundities (= female progeny) are
shown in Figures 1- 3 for the Puerto Rico, Israel and
Utah
males)
Muscidifurax
mated with M. uniraptor males in Figure 5. Fecundity
of the thelytokous hybrid resulting from the latter cross
ISRAEL-( P- 1 )
raptor
20 -
o _o
16 -
i'
.,•
q
TOTAL HOSTS
KILLED
O
-
d
Rd= 160. 01
q•
r
5.
I`-
•
•
e TOTAL"
8-
i
d
-'
PROGENY
d= 0. 1817
%.
AA
1r, -,.Rt= 111. 60 •
4 -
rf= 0.1705
o
I
I
l
I
I
I
l
I
1
1
4
I
1
1
I00
t•
20 r
Z
0. 752
O 16 O
j
R°=
a-
O
75. 78
rm= 0.1588
12 -
0. 50 (
Z
Q
Z
O
8-
m.z
O
0. 25a0
4-
0
I
3
4
i
i
I
I
I
I
I
5
6
7
8
9
10
1 1
AGE
Figure 2.
Survival
OF ADULT
I
2
I
I
I
13
14
15
1
0
16
FEMALE ( days)
1x), and daily fecundity ( m,) (= female progeny), male progeny, total progeny
t,), and host destruction( dx) for 18 mated females of the Israel strain of Muscidifurax raptor,
rate (
day.
at
25.5±
1° C.
and
55% RH. on 20 Musca domestica puparia per
DECEMBER, 1987
is
shown
The
BULL SOC VECPOR ECOL
in Figure 6.
fecundity of the
4, TABLE 1).
P93.05)
expressed largely during the last half of the oviposition
Utah
presence of the
affect on the
had
male
Israel
strain(
However, there
reduction
in
521
total
was
and
progeny
Figure 4, TABLE 1).
Microparasitoids also
no significant
period (
Figures 2
appeared, which were typically found in the Utah strain
a
and
significant
(
host destruction
Muscidifurax
Figure 3). The resultant hybrid mated to M. uniraptor
males, shown in Figure 5, resembled the Utah parent in
raptor
UTAH-(
P- 1 )
TOTAL HOSTS
KILLED
20
0.
r`
1A
Rd= 216. 60
0.
16
0. 1899
O._
Qrd=
(. `% .
TOTAL `
PROGENY '"
p
1
p._ p.._0
12
Q
Rt= 183. 78`,
rt = 0. 1858
8
0""
4
d'+? MICROS
d MICROS
0
I 00
R°=
152. 46
rm= 0. 1779
20 r
Z
0
-
0. 75 Z
O
16 -
5
Ci
Z
12 -
W
0. 50
Z
O_
8Q
O
0. 25 Q4 - •...•
d
a.
O
cc
w.
vr
•
i
i
t
i
i
t
i
i
t
i
t
t
i
t
3
4
5
6
7
8
9
10
11
12
13
14
15
16
0
AGE OF ADULT FEMALE ( days)
Figure 3.
Survival
t),
1x), and daily fecundity ( m.) (= female progeny), male progeny, total progeny
and host destruction( dx) for 10 mated females of the Utah strain of Muscidifurax raptor,
rate(
day.
at
25.5±
1° C.
and
55% RR on 20 Musca domestica puparia per
522
total
a
progeny
significantly
day
production and
reduced
were
host destruction, but had
Pattern of this latter part of the reproductive period
9th
corresponded closely to the first half of the reproductive
fecundity(
of oviposition when
high
P50.01)
after the
period of thelytokous M. uniraptor ( Figure 1).
numbers of male
by
observed, accompanied
output of
DECEMBER, 1987
progeny
drop in the
a rapid
female progeny ( Figure 5, TABLE 1).
Muscidifurax
Data for the ensuing double hybrid ( Figure 6)
correspond closely to that of the Puerto Rican parent
The
ISRAEL9 X UTAHd
raptor
20
16
TOTAL HOSTS
N. %
2
^,
O
i
d
•
R
KILLED
!\
/
Q Rd= 124. 0
'' "•
i
d
w '
PROGENY
6
rd= 0. 1752
TOTAL ..
Y
4
lF-+'`•
4
Rt= 85. 1
rt= 0. 1634
MICROS
0
1. 00
x
x
4t
20—
CD
r
Z
w
00
0.75 Z
16-
cc
p
cc
R0=
12-
70.2
0.50
rm= 0. 1560
mx
O
U
0.25
4-
0-
A...• I
I
0t
3
4
5
6
7
8
9
AGE OF ADULT
Figure 4.
Survival
O
0_
O
10
1 1
y...
12
13
14
15
0
16
FEMALE ( days)
1x), and daily fecundity ( m.) (= female progeny), male progeny, total progeny
tx), and host destruction( dx) for 10 females of the Israel strain of Muscidifurax raptor, mated
rate(
with random males of
RH.
on
the
Utah
20 Musca domestica
strain and
puparia per
day.
at
25. 5±
1° C. and 55%
DECEMBER, 1987
Figure 1),
had been
indicaring
that the typical thelytokous form
Its
produced.
female offspring
continued production of some
the 15th
day
in the
of oviposition and
micmparasitoids (
differed only in
character
Figure 6).
All
through
from tested virgin females.
female offspring
ISRAEL9
Although such changes of progeny sex ratio to
M. uniraptor
raptor
X UTAH d,)
TOTAL HOSTS
KILLED
p•
20
diagramed in Figure 5 reproduced by thelytoky,
regardless from which part of the oviposition cycle they
emanated, as judged by the female progeny produced
a
appearance of
Muscidifurax
o.-
523
X
o_
Q
o--
3?
o.-•°'
Rd= 214. 7
rd= 0. 1893
p...
16
w
1"
Z
r-''•"%
TOTAL
PROGENY
\
-'
4•
No.
r-'\
12
Rt= 183. 8
rt= 0. 1830
O
Q
8
4
Qg MICROS
0
1. 00
Qx
20 -
c9
Z
0
cr
a_
—
0.75 Z
16 -
Ro= 109. 4
r
-
0. 50
8-
0.25
4-
4
3
4
5
6
7
8
9
AGE OF ADULT
Figure 5.
Survival
rate (
1x),
and
daily fecundity(
10
II
12
13
14
15
16
FEMALE ( days)
m) (=
female progeny), male progeny, total progeny
tx), and host destruction( d) for 10 hybrid ( Israel female X Utah male) female Muscidifurax
raptor
25.5±
mated with random Muscidifurax uniraptor males and ovipositing continuously at
and 55% RH. on 20 Musca domestica puparia per day.
1° C.
DECEMBER, 1987
524
different anatomical types of sperm are known in this
males after mating with M. uniraptor males
Figure 5) may involve sperm depletion after the 9th
oviposition
day ( Legner 1987a), this is not strongly
favor
suspected
in the
viable sperm
in
16
day
old
females.
A second possibility considers the involvement of
extranuclear factors in the induction of thelytoky as was
However,
Muscidifurax
ISRAEL
y
M.
raptor
X UTAH( 1)
TOTAL HOSTS
which may also differ in
fertilization capabilities.
present case as spermathecae contained
all >
1967),
McCoy
species (
uniraptor
X
VIRGIN
d
]
KILLED
20
yr
d
1
\•
Rd
TOTAL
PROGENY
16
rd
d
4. 0
0? 914
s-- 1
•
z
Rt= 197. 1
12
rt= 0. 1870 If
C7
8
4
MICROS
c( MICROS
0
1. 00
x
1
20 r
z
a.
0. 75
_
Z
O16 -
dd
CC
_
p
12 -
o:
R0=
Z
m=
35422
z
0
p
0
8-
0. 25
m
x
4-
a
0
0
4
3
6
5
7
8
9
AGE OF ADULT
Figure 6.
Survival
ç), and
rate (
RR
on
1x),
and
X
10
II
12
13
14
15
16
FEMALE ( days)
daily fecundity ( mx) (= female progeny), male progeny, total progeny
host destruction (
males) females
a
0
Cayey
dx)
for 16
virgin
malesifemales,
20 Musca domestica
double hybrid females , [( Israel females X Utah
puparia per
day.
at
25. 5 ±
1° C. and 55%
DECEMBER,
1987
inheritance
shown with the
Muscidifurax
1986,
of gregarious oviposition
Kogan
raptorellus
Extranuclear
1987b).
Beale
phenomenon among
Knowles 1978), and
and
known
males
to alter
sex
females ( Krell
or
Vinson 1977, Stoltz
Werren
et al.
1986),
et al.
in
ratios
or
primitive
a
and
A third
legacy
chemical
hypothesis
another part) of the next-to-be-oviposited ova, and from
and
here they influence endomitosis in the next generation,
Stoltz 1986,
thelytoky would be passed on without genetic change.
other
assumes that at
certain
chemicals
modify reproduction. The finding that
duction is influenced in a way that depends on the
the male
could
be
from the
chemical
modifying
explained
by
a
male
repronature
reproduction-
as
well
as
by
(
With such a system, it is possible to envision
quantitative variation in microorganisms and enzymes
or other) and hence the number of thelytokous females
produced. Because the titre appears to build up during
host-free periods ( Legner 1985a, Legner and Gerling
1967),
following
and
affect
Reports
1984),
Carde
Venturia ( Nemeritis)
heneicosane
involved) ( Mudd
was
1983, Richmond
behavior
involving
Gravenhorst) (
where
and the
Mane
and/ or
proceed relatively slowly.
thelytoky also could be fixed in a hybrid M. raptor
population by backcrossing to one of the parental males,
but
not to
both( Legner 1987a). Thus, if each strain or
species of parasitoid harbored its own specific strain of
Prostaglandins,
microorganism, only certain crosses of the latter may
fatty acids, alter
Stanley- Samuelson and
chemosensory
points to the probable specificity of any such microorganisms which may be involved. It was found that
et al.
of certain polyunsaturated
egg laying behavior in crickets(
Loher 1986). It has been suggested that
the
1982);
et al.
enzymes (
Senior 1981).
and
insects
of
include a lepidopteran
an ichneumon
wasp
canescens (
dipteran Drosophila
derivatives
multiplication
There is another aspect to thelytoky induction that
substances
mating.
Webster
microorganismal
elaboration of the chemical substance(s) would have to
microorganisms.
Chemical
If, for example,
thelytoky.
from the male' s seminal fluid into the chorion ( or
which
of
of
are
altering behavior in
receive
inheritance
by killing
Metazoa ( Bull 1983).
insemination females may
the
microorganisms and their accompanying capacity to
produce chemicals or inducing enzymes are transferred
organisms
Stoltz 1979, Stoltz
1976, Vinson
The last two hypotheses preclude a genetic aspect
to
well-
microorganisms
parasitoids
and
by
is
heredity
documented
in
Legner ( Legner
and
525
an
responsiveness of an
influence
individual
yield a strain capable of affecting the endomitotic
Continued biochemical and microbiological
process.
on
investigations are expected to elucidate further the
by
pathways to inheritance of thelytoky.
chemical cues derived from its parents would be hard to
distinguish from
a genetic effect ( Corbet
1985).
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Whatever the agent for induction of thelytoky,
there is
an
apparent
factor.
causative
relationship to the titre of the
For example, production of
thelytokous females in M. uniraptor
host
presentation on alternate
by scheduling
days( Legner 1985a) or by
slowing oviposition rates during early adult life( Legner
and Gerling 1% 7). Such interferences may allow the
factor to
titre of the
microorganisms
or
Higher
rise.
chemicals
could
reasonably be
concentrations of
may thus
greater proportion of thelytokous
assumed that
Edward Arnold, London.
guarantee
female offspring.
both
a
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Heat treatment ( 32.2° C. for> 24- h) beginning at a
143- 153.
with
the
critical
and
in
oocyte
progeny
microorganisms
promoting
either kill
produced are,
latter
stage
male
they
are
result (
Legner
endomitosis
legacy hypothesis.
Duncan, D. B.
tests.
1955.
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Multiple range and multiple F
Biometrics 11: 1- 41.
1985b).
involved directly
or
If any
indirectly in
higher temperature may
inactivate them.
Earlier work ( Legner
endomitosis,
or
formation blocks
Evolution of Sex Determining
Mechanisms. The Benjamin/ Cummings Publ. Co.,
involved,
and certain chemicals that
142 pp.
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is interrupted for 24 hours
oviposition
Beale, G. and J. Knowles. 1978. Extranuclear Genetics.
the
1985b) also would point to their probable residence in
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Kawooya, J. K.
1983.
Electrophoretic discrimination
526
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of
four
new
Apanteles
Spalangia
Nasonia
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raptor,
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changes
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Mane, S. D., L. Tompkins, and R. C. Richmond. 1983.
Male esterase 6 catalyzes the synthesis of a sex
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females.
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Hymenoptera
host densities. Ann.
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Hymenoptera: Pteromalidae)
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Ph.D. Dissert.,
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1985a.
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changes
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Muscidifurax
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Ptero-
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Mudd, A. R., C. Fisher, and M. C. Smith. 1982. Volatile
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Effects
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(
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Ptero-
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Breeding
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oviposition
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Inheritance
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and
insect
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poultry
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Baculovirus-like particles in the reproductive
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Stoltz, D. B., S. B. Vinson,
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E. A. Mackinnon. 1976.
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231: 990-992.
DECEMBER, 1987
SOME QUANTITATIVE ASPECTS OF INHERITANCE IN BREEDING
SYNANTHROPIC FLY PARASITOIDS
E. F. Legnerl
The inheritance of solitary and recessive gregarious oviposition behavior in two strains of
ABSTRACT:
Muscidifurax raptorellus Kogan and Legner appears quantitative, as successive backcrosses of hybrids to original
parental males result in additive intensities of trait expression. The magnitude of each increase is dependent on the
number of backcrosses that were performed to create the hybrid, the particular" load" of backcrosses that a hybrid
possesses determining the degree to which the next mating will affect behavior. The curve for increasing expression
of behavior appears sigmoid. Females changed their behavior significantly immediately following mating. Thus,
for biological control the liberation of parasitoid males possessing certain desirable traits, such as high fecundity
or parasitization rates might be a rapid way to enhance control of target hosts by causing expression of the trait in
feral females with whom the males mate, as well as by the resultant offspring.
genus, Muscidifurax raptorellus Kogan and Legner,
INTRODUCTION
in distinctive
occurs
The
Muscidifurax
genus
Pteromalidae)
a
contains
( Hymenoptera:
of
group
related
closely
parasitoid species which attack puparia of synanthropic
Diptera
and, thus, are
five described
the Nearctic and
are sympatric
Kogan
beneficial in
species occur
Neotropics,
in the
western
in
Girault
and
equatorial
1987).
The Chilean strain compensates a lower host
greater number of
progeny
per
host( Legner 1967).
In
known to involve a process whereby the female
parasitoid first expresses some of the trait shortly after
not
and portions of the
Pacific
area
Olton 1968, 1971, Legner
and
et
mating with the male bearing it, and then passes it to her
offspring where it is fixed into their genome and
been found in the Neotropics
and
demonstrated
has
not
Extranuclear
clinal patterns.
The
genus
is poorly represented in
Legner 1983, Legner and
and
regions (
Muscidifurax spp.
decaying
or their
host densities ( Kogan and Legner 1970, Legner 1967,
searching capacity with gregarious behavior that nets a
and
are most prevalent
organic
livestock
wastes
where
they
in
in
the virgin
state ( Legner
1986).
phenomena were thought to be involved
in this scheme which was called" accretive inheritance."
et al.
The present study was performed to measure the
fixation of heritable behavior in a succeeding series of
or near
backcrosses to hybrids created through reciprocal
crosses between the Peruvian and Chilean strains of M.
Olton 1968, Legner
1976).
humans
in
Muscichfurax
Greathead 1969, Legner
accumulated
is > 60 percent gregarious
Sanders, is distributed in Europe,
from Asia
reported
humid
Chile
central
this species the inheritance of certain behavioral traits is
there are no known
been
from
ovipositional and developmental behavior at defined
The
Legner 1972, Legner
1976); but has
coastal Peru is predominantly solitary, while another
Nearctic ( Kawooya 1983,
Legner 1970, Legner 1969, 1983).
and
Africa, North America,
al.
isolation in
One strain from
except two species which
suspected ancestor of this apparent clade,
raptor
The
natural control.
geographic
populations.
deposited
parasitize
by
host
raptorellus for the purpose of breeding superior
parasitoids for biological control.
Diptera that also breed selectively in this habitat. Thus,
they fit
the
endophilous
eusynanthropic
Legner et al. 1974, Povolny 1971), and their existence
largely is dependent on herdsmen. This has led to the
suggestion
that
the
four
species
category
presently
confined
To study fecundity and parasitization, cohorts of 10
one-day-old female parasitoids were isolated in
wholly to the Americas could have evolved within the
recent time period of European settlement or during the
screened, 46 cm' polystyrene vials with a basal area of
den Assem
or were mated to Chilean or Peruvian males for one day.
Fart female was supplied daily with 20 24-to 30-h-old
the
puparia of Musca domestica L., 6.4± 0.5 mm X 2.8± 0.2
Kogan
past
400
and
Povel 1973).
years(
and
Legner 1970,
The only known South American
University
of
California, Division
of
van
member of
7 cm 2.
Females were either allowed to remain virgins
Biological Control, Riverside, CA
92521, USA.
DECEMBER,
1987
distributed randomly over the vial base, and which
had been reared until pupation using commercial
CSMA® medium. Parasitization efficiency at this host
mm,
529
second through tenth days of oviposition, their daily
values approximating the averages shown in TABLES
1 and 2 ( note low standard deviations).
density and in this environment at 25.5° C was near
optimum (
Host
24- h
a
Legner 1967, 1979).
were
incubated
13L: 11D
at
25. 5±
1° C, 55
puparia
remaining
gelatin capsules (
were
10 X 25
of ca.
25 ft-c( 269 lux)
Females changed their behavior significantly
following mating, as previously observed in this species
and
( Legner 1986).
until
mm)
died( ca. 9 days). The
incubated separately in
cantly
for the
F1
gregarious capability of Chilean females with whom
dissected
they mated ( TABLES 1, 3, and 5). This was true
whether the matings were with females of each original
strain or their hybrids( FABLES 1 and 2). Also, Chilean
emergence of
puparia were
Parasitoid
longevity,
for
each
total progeny, and sex ratio
female for 16 days, which is ca.
the one- half
life expectancy of
The importance of extended
more
eggs
However, Peruvian
gregariously.
males of solitary heritage significantly reduced the
aborted parasitism.
were recorded
A Chilean male of gregarious heritage
mated to a Peruvian female caused her to lay signifi-
and
then
progeny. Unemerged
parasitoid
RH,
percent
for
by fluorescent lamps,
photoperiod supplied
giving a table- level intensity
adult flies ceased to emerge
for
Effects of Mating on Female Behavior
puparia that were exposed to parasitoids
females mated to males of their own species tended to
females.
increase gregarious oviposition and significantly
experimental time for
viewing behavior accurately is becoming recognized
for other parasitoids ( Hey and Gargiulo 1985) and
Drosophila ( Templeton 1982).
increased the number of hosts they parasitized if the
Three
series
temperature
conducted
identical
of
and
over
a
a population of
experiments
replicate
two year
strain had a distinctively higher oviposition rate
TABLE 2). However, no other significant quantitative
slight
with
modifications
were
but the
mating was with a Peruvian male ( TABLE 1) whose
effects were noted with host attack rates and mating
(
TABLE 3).
Dissections of unemerged puparia and
results
aliquot replicates in these experiments eliminated the
consider only the last experiment,
differ appreciably from the previous two.
Experiments were conducted in a completely
possibility of differential egg or larval mortality, and
herein
reported
which
did
random
on the
period,
not
design.
Analyses
of variance were performed
binomial data transformed
as
follows:
the arcsin
of the square-root of the percent response was used
percent gregarious oviposition; the square-root of
2 for
for
X+ 1/
number of parasitoids per gregarious oviposition;
and the
log( base
parasitized (
Steel
10)
of
and
X+ 1/ 2
was used
Torrie 1960).
for
total
hosts
Duncan' s ( 1955)
multiple range tests were performed on the transformed
data,
and
although
significance was
only the P<0.05 level is
detected at P<0.01
frequently
shown,
less.
or
verified variable intensities of solitary or multiple ovipositions as true behavioral changes following matings.
Mother comparatively weaker measurement
pertaining to oviposition behavior was the total number
of parasitoids
that developed
per gregarious
These showed many significant parallel
oviposition.
trends with percent gregarious oviposition ( TABLES 1
and
2).
Ancestral Chilean virgins produced the highest
number of parasitoids ( 3. 13 to 3. 33) per
gregarious oviposition, but all subsequent hybrids
average
possessing various proportions of Peruvian heritage
never attained this high level ( TABLES
1 and 2).
Gregarious behavior was entirely eliminated in the third
RESULTS
Reciprocal
crosses of the two
backcross to Peruvian males ( TABLE 2).
M. raptorellus
strains
heterozygous for
and
gregarious
oviposition,
(
1 and 2).
TABLES
solitary
Resultant Fl hybrids appeared heterotic with respect to
produced
offspring
which
greater parasitization rates (
were
TABLE 3).
Successive backcrosses to either original parental
produced
hybrids which showed either
quantitative increases or decreases in the percent of
male
hosts that
were
number of parasitoids
and
2).
The
remarkably
gregariously and in the
developed per host ( TABLES 1
parasitized
expressions of gregarious
uniform
among
replicate
behavior
were
females from
the
Quantitation of Inheritance
TABLES 1 and 2 also show details of the pathways
to inheritance of gregarious and solitary oviposition
behavior.
The average daily percent gregarious
ovipositions for the Chilean strain of M. raptorellus
ranged from 80.9 to 66.6 percent for mated and virgin
females, respectively; while no gregarious oviposition
was observed
in the Peruvian
strain(
TABLE 1).
Mating
Peruvian males with Chilean females reduced the
latter' s gregarious virgin oviposition significantly to
56.1 percent, a quantitative drop of 15.8 percent.
However, mating Chilean
males with
Peruvian females
increase their
the latter to
caused
oviposition rate
The
8.5
significantly to
hybrids
virgin
showed
gregarious
ca. two-thirds reduced
and
However,
2).
matings with
Chilean
performance, while
from Chilean
Peruvian
These differences
1).
by
percent, as tested
test.
Similar
in the
as
males
results are
all
were
s(
found in
were
tons between
significant (<
the
and the number of
a Chilean male was ca. one-half that observed
it( FABLE
subsequently in resultant hybrid progeny. This can be
seen by referring to the values for virgin hybrids in
0.05
TABLES 1 and 2. The origin of males from haploid ova
multiple range
the
in these Hymenoptera might logically explain this
first,
at <
second, and
2).
0. 01)
quantitative difference, while in diploid virgin hybrids
the particular expression ca. doubles.
correla-
The quantity of gregariousness or solitariness that
ovipositions
was inherited in each backcross differed according to
positive
percent of gregarious
individuals
evoked in females by mating with either a Peruvian or
significant
1955)
third backcrosses ( TABLES 1 and
There
The magnitude of behavioral expression that was
TABLES
their gregarious
males reduced
Duncan'
0.858, 34 df) as
with no significant trends being related to inheritance.
case of their parents,
increased
r -
were
that
virgins (
progeny (
mated parents ranged from 62 to 80 percent females,
possessing
Peruvian parents
capabilities
and total
calculated over all tests. Sex ratios among offspring of
TABLE 1).
crosses
and
oviposition
0.923, 33 df),
gregarious
virgin
percent(
these
of
inheritance from both Chilean
1
DECEMBER, 1987
530
oviposied per
the " load" that each hybrid possessed for either trait.
host ( r=
TABLE 1. Quantitative inheritance of gregarious oviposition behavior by the Peruvian strain of Muscidifurax
raptorellus
Kogan
10 females ovipositing continuously
Leper:
and
at
25° ± 1° C., 55%
RH on 20 Musca domestica L. puparia daily for 16 days.
AVERAGE NO. PER DAY/
Gregarious Oviposition'
Female
Lineage
of
Female
Virgin
Mated to
Female
Chile Male
0
P, Peru Female
8. 5
Parasitoids developed per host'
Female
Female
Mated to
Virgin
Mated to
Peru Male
Female
Chile Male
1. 00
0
with
Chile Male
19.
48
48.
4. 5)
(
5b
4. 5)
9. 3)
0. 22)
2. 07'
10.4`
0. 19)
Female
Mated to
Peru Male
2. 00
0)
4. 9)
F, hybrids
Stand.-dev.
2.
(
35b
0. 10)
1. 00
(
0)
2.038
0.31)
Backcrosses to Chile Male
1st
64.
58
68.
14. 6)
2nd
66.
9. 1)
3rd
9. 2)
(
3a
28
75.
(
9b
43.
0b
2.
11. 0)
0.40)
34. 8'
5. 2)
658
2.
(
2. 84'
3. 1)
0. 42)
78. 2
94b
0. 33)
3. 26'
(
0. 14)
2.57'
0.47)
2. 18b
0.04)
2.92
5. 2)
0.40)
Backcrosses to Peru Male
1st
1. 3'
1. 3)
2nd
1. 5
1. 8)
28.
(
8b
10. 8)
2.
3a
1. 8)
2. 00'
(
0)
2. 15'
0. 11)
2.22'
0.70)
2.00
0)
Values within a row followed by the same letter are not significantly different ( P<0.05; Duncan' s [ 1955]
multiple range test).
DECEMBER,
For
1987
example,
hybrids
with a single gregarious ancestor
Peruvian male decreased the expression by 93.3
expressing a higher rate of gregarious
behavior if mated with a Chilean male than those whose
lineage showed one, two, or three backcrosses to a
Chilean male ( TABLES 1 and 2).
Similarly, hybrids
backcrossed to a Peruvian male progressively lost
were capable of
gregarious
instincts,
only slightly
these gains
or
progeny
of the mated
backcrossing
Chilean
male
a
percent. However, in the second backcross the addition
of either Chilean or Peruvian influences through mating
caused increases or decreases whose magnitude
depended on the lineage of the hybrid( TABLES 1 and
2).
The curve for adding additional magnitudes of
the rate of loss
decreasing
first backcross. The reflections of
losses were obvious in the resultant
after the
19.4
with
hybrids( TABLES 1
percent gregarious
increased
progeny by 232
in
gregarious expression
( refer to data for virgin females in TABLES 1 and 2).
a
Because males are able to activate portions of their
virgin
genetic make-up within their own generation, through
backcross
percent, whereas, the
gregarious or solitary ovipositional expression,
beginning with the original parental strain, and through
the first, second, and third backcrosses, seems sigmoid
2). Thus,
and
F, hybrid to
531
to a
causing immediate expression of some unique traits in
TABLE 2. Quantitative inheritance of gregarious oviposition behavior by the Chilean strain of Muscidifurax
raptorellus
Kogan
and
Legner: 10 females
at
25°±
1° C., 55%
RH on 20 Musca domestica L. puparia daily for 16 days.
AVERAGE NO. PER DAY / Stand.-dev.
Gregarious Oviposition'
Female
Lineage
Female
of
P, Chile Female
Virgin
Mated to
Female
Peru Male
66. 6°
56. 1"
14. 5)
F, hybrids
with
Peru Male
(
21. 1'
5. 3)
Virgin
Chile Male
Female
9. 5)
8. 1"
41. 4°
2. 1)
Female
Mated to
80.9'
7. 7)
(
Parasitoids developed per host'
Female
6. 8)
Mated
Peru Male
3. 13'
2. 56"
0.67)
0.22)
2. 10'
0.07)
to
2. 10'
(
0. 18)
Female
Mated to
Chile Male
3. 33'
0.52)
2. 3?
0. 12)
1st
5. 1°
3. 5°
3. 9)
2nd
(
0. 4'
6. 8)
0. 2°
0. 8)
3rd
22. 5"
0. 1)
(
0
2. 00'
0)
2. 00°
0. 2)
0)
0
1. 00°
0)
2. 00°
0)
2. 10°
0. 10)
2. 00°
0)
1. 00'
0)
1st
61. 8°
12. 0)
2nd
(
69. 7°
6.6)
3rd
29. 1"
81. 9
11. 0)
35. 1"
(
-
15. 1)
66. 3'
(
13. 6)
68. 3°
3. 1)
2. 536
0. 35)
2. 72°
0. 23)
2. 23'
0. 16)
2. 29"
0. 23)
2. 78"
0. 22)
2.8?
0. 28)
3. 12
0.67)
DECEMBER, 1987
532
TABLE 3. Total hosts parasitized by the Peruvian and Chilean strains of Muscidifurax raptorellus Kogan
Legner and their hybrids:
and
10 females ovipositing continuously
at
25°±
1° C.
and
55% RH
on 20 Musca domestica L. puparia for 16 days.
AVERAGE TOTAL HOSTS PARASI L IZED /
Original Chile Female Line'
Original Peru Female Line
Female
Female
Mated to
Virgin
Mated to
Mated to
Chile Male
Female
Peru Male
Chile Male
79. 5
43.0'
71. 8b
53. 0'
Female
Female
Generation
Virgin
Mated to
Female
Peru Male
84. 2
F,
85.0
16. 7)
(
10. 1)
12. 1)
23. 7)
25. 3)
18. 7)
113. 1
109. 0
95. 2
16.4)
(
18. 7)
18. 9)
11. 4)
106.2
102. 7
F, Hybrids
Stand.-dev.
105.0
12. 0)
23.6)
94. 0
1st
81. 6
14. 2)
(
13. 9)
(
22.2)
19. 8)
7. 1)
15. 5)
13. 1)
10.5)
113. 8
14. 1)
12. 1)
112. 5
9. 9)
113. 8
3rd
114. 8
24. 1)
93. 2
97.4
90. 1
78. 7
98.6
2nd
88. 8
84. 0
95.7
25.8)
13. 1)
17. 2)
(
74. 8
80.8
84.4
70.4
1st
17. 7)
55. 2
99. 8
2nd
78.4
15. 1)
16.4)
16. 1)
82.2
80. 2
3rd
15. 3)
65. 2
14. 5)
9. 6)
89.4
15. 8)
14. 2)
16.4)
the
females
with
whom
they
mate,
Acknowledgments
selection pressure
begins within their own generation, not having to wait
for
only may
for
I am especially grateful to Dr. J. C. Luhman for his
assistance and diligence in counting data of preliminary
elimination of unfavorable genes, as suggested
experiments which established behavioral trends and to
expression
in
the
functional haploid
the rapid
by Dobzhansky (
the
pace
of
F, progeny. Thus,
1941), but they may
natural
undesirable and
not
parasitoid males provide a means
selection
desirable
serve to quicken
for both
characteristics
nonlethal
as well.
For
Mr. R. W. Warkentin for his care in the preparation of
age- classed
hosts
and parasitoids.
Financial support
was provided by Rincon- Vitova Insectaries, Inc.
inundative biological control, the liberation of males
possessing certain desirable traits, such as high fecun-
REFERENCES CITED
dity or parasitization rates might cause feral resident
females
with whom
enhance their
impact
Dobzhansky,
against
the target
as
produce a
hybrid
Species.
population
that
they mate to
host, as well
demonstrates
such qualities.
T.
1941.
Genetics and the Origin of
2nd Ed. Columbia Univ. Press, New
York, 428 pp.
DECEMBER,
1987
533
Assoc. 54: 156- 159.
Duncan, D. B.
tests.
Hey, J.
and
1955.
Multiple range and multiple F
Biometrics 11: 1- 41.
Legner, E. F. and D. J. Greathead. 1969. Parasitism of
pupae in East African populations of Musca
M. K. Gargiulo. 1985. Sex- ratio
Leptopilina heterotoma in
response to
changes
breeding.
in
domestica
J.
Entomol. Soc. Am. 62: 128- 133.
Stomoxys
and
calcitrans.
Ann.
of Heredity 76: 209-211.
Legner, E. F.
Kawooya, J. K.
of
1983.
species
the
of
Pteromalidae)
Electrophoretic discrimination
parasites
Muscidifurax ( Hymenoptera:
PhD. Dissert., Univ. of
Muscina,
G. S. Olton.
and
from
1968.
Diptera:
Activity of
Musca domestica,
Stomoxys calcitrans, and species of Fannia,
complex.
Illinois, Urbana, 113 pp.
and
Ophyra II.
At sites in the Eastern
Hemisphere and Pacific area. Ann. Entomol. Soc.
Am. 61: 1306- 1314.
Kogan, M.
E. F. Legner.
and
1970.
A biosystematic
revision of the genus
Muscidifurax ( Hymenoptera:
Pteromalidae)
descriptions
with
of
four
Legner, E. F. and G. S. Olton. 1971. Distribution and
new
relative abundance of dipterous pupae and their
Canad. Entomol. 102: 1268- 2190.
species.
parasitoids in accumulations of domestic animal
manure in the southwestern United States.
Legner, E. F. 1967. Behavior
changes the reproduction
Hilgardia 40: 505- 535.
of Spalangia cameroni, S. endius, Muscidifurax
raptor,
Nasonia
and
Pteromalidae)
Hymenoptera:
Legner, E. F., I. Moore, and G. S. Olton. 1976. Tabular
host densities. Ann.
keys and biological notes to the common
vitripennis (
increasing fly
at
Entomol. Soc. Am. 60: 819- 826.
parasitoids of synanthuopic Diptera breeding in
accumu- laced animal wastes.
Legner, E. F.
1969.
Reproductive isolation
variation in the Muscidifurax raptor complex.
Entomol. News 87:
113- 144.
and size
Legner, E. F., R. D. Sjogren,
and
I. M. Hall.
1974.
Biological control of medically important arthro-
Legner, E. F. 1972. Observations
hybridization
on
and
pods.
Crit.
Rev.
Environ. Contr.
4: 85- 113.
heterosis in parasitoids of synanthropic flies. Ann.
Entomol. Soc. Am. 65: 254- 263.
Legner, E. F. 1979.
effects
on
Prolonged
reproductive
parasites of muscoid
Povolny, D. 1971. Synanthropy: definition, evolution,
culture and
rates
flies.
two
of
and classification. Pp. 17- 54, in Flies and Diseace,
Ecology, Classification and Biotic Associations (
B. Greenberg, ed), Vol. I. Princeton Univ. Press,
Princeton, NJ, 856 pp.
inbreeding
pteromalid
Ann. Entomol. Soc.
Am. 72: 114- 118.
Steel, R. G. D. and J. H. Torrie. 1960. Principles and
Legner, E. F.
1983.
parasites
associated
synanthropic
Spalangia
Broadened
flies
endius
and
Muscidifurax
view of
with
species
sibling
Procedures of Statistics with Special Reference to
the Biological Sciences. McGraw-Hill Book Co.,
endophilous
in
the
Inc., NY, 481 pp.
Proc. Calif. Mosq.
complex.
Vector Contr. Assoc. 51: 47-48.
Templeton,
A. R.
parthenogenesis.
Legner, E. F.
1985.
in
changes
Natural
and
populations
Muscidifurax
uniraptor
Pteromalidae).
Ann.
induced
Entomol.
The
prophecies of
Evolution and
Genetics of Life Histories ( H. Dingle and I. P.
ratio
Hagmann,
thelytokous
of
(
sex
1982.
Pp. 75- 101, in
Hymenoptera:
eds.),
Springer-Verlag, New York/
Berlin.
Soc. Am. 78:
398- 402.
van
den Assem, J.
and
G. D. Povel.
1973.
Courtship
behavior of some Muscidifurax species ( Hym.,
Legner, E. F.
1986.
Diptera using
mechanism.
a
Breeding
novel
superior parasitoids of
extranuclear
Proc. Calif.
Mosq.
inheritance
Vector Contr.
Pteromalidae): a possible example of a recently
evolved
ethological
isolating
Netherlands J. Zool. 23: 465-487.
mechanism.
DECEMBER,
BULL SOC. VECTOR ECOL, 12( 2): 534- 538
1987
MEDICALLY IMPORTANT AND OTHER ECI'OPARASITIC ACARINES ON
VERTEBRATES FROM SANTA CATALINA ISLAND, CALIFORNIA
S. G. Bennett'
Santa Catalina Island is
Islands
which
lie
off
km from Los Angeles)
is
and
southern
least
the
Channel
California( 32
most frequently on their hosts in the winter. Eggs that
hatch in the spring produce larvae which diapause until
studied of the
the fall ( Furman and Loomis,
eight
of
one
the coast of
Channel Islands as relates to mites and ticks. Lane et
1983)
ixodid ticks from the
reported argasid and
Channel Islands, but only mentioned the record of
from Santa Catalina taken by Gus
pacificus
Augustson in January of 1941( Cooley and Kohls, 1945)
during the Channel Islands Biological Survey of 19391941. Cooley and Kohls ( 1945) also recorded Ixodes
Ixodes
Dermacentor
United States. The only records presented here are from
Cooley and Kohls ( 1945).
pacificus,
I. brunneus,
insular
the
on
occurs
Channel Islands, it has
most important with regards to human health. Nymphs
from Santa
and adults will readily bite man and domestic animals
trombiculid mites( chiggers)
such as dogs and horses. One adult female was found
of
the
been
other
reported
Kayella lacerta
and
from East Anacapa Island
Loomis( 1962), but
lizard
relatively
Catalina Island. All
paper are
were
This
the author unless otherwise noted.
for
and
for
locality data
in TABLES 1
specimen
the Lyme Disease spirochaete( Borrelia burgdorferi) to
humans in California. Ixodes pacificus is a winter tick
and
2.
by
from Santa
all records are
Additional
and is most active from November through May
and
taken
represents a
of ectoparasitic acarines
presented
suggests that I.pacificus is responsible for transmitting
these
Santa
for Santa Catalina Island
from 1979 to 1987
preliminary study
Catalina. Host, date,
and
other records of acarines presented
new
specimens collected
for
from
ectoparasites
attached to the author' s stomach after walking through
high grass and coastal sage. Epidemiological evidence
were
Powder
by
no published records exist
common
California, particularly in coastal regions, and is the
Ixodes
California
not yet
Eutrombicula belkini
tick
endemic
some
Catalina Island. The larval
reported
Ixodes pacific us ( Western Black- legged Tick)
This is the most common species of Ixodes in
and
albipictus.
Although
peromysci
used
brunneus
A common parasite of birds found throughout the
from Santa Catalina Island and Furman and
Loomis ( 1984) listed I.
in this
The two adult
beneath rocks near deer trails.
other
Ixodes
brunneus
1984).
females collected by the author were found alive
al.
references
identification included Evans
and
(
Furman
and
and
Loomis, 1984).
nymphs
from
the
The collection of larvae
side- blotched
lizard ( Uta
stansburiana),
the
skink (
Eumeces
and
from
a
Capra hirca)
one
adult
goat (
skiltonianus),
on Santa
Catalina Island all constitute new records for this
tick.
Till ( 1966), Krantz ( 1978), and McDaniel ( 1979) for
Bennett ( 1977),
mesostigmata;
1977),
and
Brennan
Loomis ( 1956, 1971) for
and
Goff
tmmbiculidae.
MACRONYSSIDAE
Ornithonyssus bacoti ( Tropical Rat Mite)
A single specimen was recovered from a small
DISCUSSION
child in the city of Avalon. All members of the child' s
family had suffered from numerous red pustules on their
bodies and severe itching for several weeks following
IXODIDAE
Dermacentor
This
tick
albipictus (
coastal
in September
their
primarily on large herbivorus
commonly on horses and deer) and is
distributed
including
throughout
California.
with
larvae
County
Activity
through
of
The mite was seen crawling on the child' s body and was
The
removed with a piece of tape by the mother.
America,
specimen was mounted on a slide and cleared in
larvae begins
Polyvinyl Alcohol-Lactic Acid mounting media.
North
and nymphs
hosts from September
Orange
the removal of a rat infested tree adjacent to their home.
Tick)
occurs
mammals ( most
widely
Winter
being found
April.
Adults
on
are
Additional mites were recovered from a single Rattus
rattus at Toyon Bay.
Vector Control District, 13001 Garden Grove Blvd., Garden Grove, CA
92643
USA.
DECEMBER,
1987
Ornithonyssus
sylviarum
(
Northern
Ophionyssus
Fowl
Mite)
Hundreds
from
removed
rustica)
nest
larvae,
of
an
nymphs,
where
crawling down the
floor.
they
wall
and
adults
were
of a
exiting
building
were
(
Snake Mite)
bacterium Pseudomonas hydrophilus which causes
hemorrhagic septicemia in captive reptiles. It has also
the nest and
and onto
natricis
Common parasite of snakes and lizards,
particularly in zoos and pet shops and is the vector of the
Barn Swallow ( Hirunda
abandoned
535
been recorded from rats and humans( McDaniel 1979).
Gravid females were recovered from two alligator
the
TABLE 1. Records of ectoparasitic acarines from Santa Catalina Island.
L
NM
F
Locality
Date
Host or Source
METASTIGMATA
Ixodidae
Dermacentor
1
albipictus
3
5
None
7
IX- 14- 48
12
None
x
x
None
IX-2- 49
II-2- 49
1
Toyon Bay
Blackjack Mtn.
XII- 1- 84
Los Angeles Co.
II-29- 40
1
xodes
brunneus
lxodes pacificus
1
III-6- 80
Odocoileus hemionus ( Mule Deer)
Under rock
Lanius ludovicianus ( Loggerhead Shrike)
Santa Catalina Isl. I- 23- 41
Lophortyx californicus ( California Quail)
None
IX- 14- 48
Odocoileus hemionus
1
None
Isthmus Cove
1
Isthmus Cove
XI-2- 49
IV- 6- 79
IV-8- 79
Gerrhonotus multicarinatus( Alligator Lizard)
Uta stansburiana ( Side-blotched Lizard)
1
6
2
2
2
3
Isthmus Cove
X1- 13- 87
On Clothing
1
Isthmus Cove
X1- 14- 87
Human
Gerrhonotus multicarinatus
3
5
Toyon Canyon
V-2- 80
1
8
Toyon Canyon
II-22- 81
1
Toyon Canyon
Toyon Canyon
Toyon Canyon
I- 30- 82
1
1
1
Toyon Canyon
Uta stansburiana
Uta stansburiana
XII- 12- 85 Urocyon littoralis ( Island Fox)
II-21- 82
III-22-86 Canis familiaris ( Domestic Dog)
1
Toyon Canyon
I- 11- 86
Capra hirca ( Goat)
2
Toyon Canyon
II- 14- 87
2
Toyon Canyon
Sus scrofa ( Wild Pig)
I- 17- 87
Tick drag
Toyon
III-2- 81
4
2
Toyon
Bullrush Canyon
II-21- 81
Urocyon littoralis
1
Gallaghers Cyn.
V- 14- 81
Eumeces skiltonianus ( Western Skink)
Gallaghers Cyn.
II-5- 82
Canis familiaris
Blackjack Mtn.
Blackjack Mtn.
I- 26- 85
On clothing
On clothing
1
2
5
1
1
Bay
Bay
XII-4- 82
XII-1- 85
MESOSTIGMATA
Macronyssidae
Ornithonyssus bacoti
1
5
Ornithonyssus
sylviarum
Pellonyssus passeri
Ophionyssus
Dermanyssidae
Dermanyssus
L= larvae; N=
nymphs;
Human
VI- 27- 87
Rattus rattus ( Roof rat)
VI-29- 81
x
x
x
Toyon
x
x
x
x
Toyon
10
M=
V- 4- 84
x
natricis
gallinae
Avalon
Toyon Bay
x
x
adult male;
x
F=
x
Bay
Bay
Isthmus Cove
XI- 14- 87
Barn Swallow nest( Hirundo rustica)
Selasphorus Basin ( Allen's Hummingbird)
Toyon
VII- 5- 86
Barn Swallow nest
adult
Bay
female;
x=
V- 20- 82
unknown#.
DECEMBER, 1987
536
TABLE 2. Records of ectoparasitic acarines from Santa Catalina Island.
L
F
NM
Host or Source
Locality
Date
Isthmus,
V- 11- 79
Uta stansburiana
VI- 1- 79
Uta stansburiana
IV-8- 79
PROSTIGMATA
Trombiculidae
4
Eutrombicula belkini
Catalina Harbor
10
Euschoengastia
3
Cherry
9
Cape Canyon
V-25- 80
Uta stansburiana
Uta stansburiana
10
Toyon Canyon
V- 17- 80
Uta stansburiana
5
Toyon Canyon
X- 23- 81
1
Toyon Canyon
VI-28- 87
Uta stansburiana
Spermophilus beecheyi( Ground squirrel)
5
Gallahers Cyn.
V- 14- 81
Eumeces skiltonianus
2
Toyon
V
1
Bullrush Cyn.
12
ambocalis
Euschoengastia
numerosa
Euschoengastoides (
nr.)
Cove
Bay
81
Peromyscus maniculatus( Deer Mouse)
Soil sample
Isthmus Cove
XII-2- 84
XI- 14- 87
Reithrodontomys megalotis( Harvest Mouse)
1
Blackjack Cyn.
XII-1- 84
Soil sample
1
Haypress Reserv.
VI-27- 87
Spermophilus beecheyi
neotomae
Kayella lacerta
Acomatacarus
arizonensis
3
Haypress Reserv.
VI-27- 87
Spermophilus beecheyi
2
Gallaghers Cyn.
V- 14- 81
Eumeces skiltonianus
2
Cape Canyon
V-25- 80
5
Toyon Canyon
XI-7- 81
Uta stansburiana
Uta stansburiana
Toyon
IX-29- 81
Myotis evotis ( Long- eared Bat)
Myobiidae
Pteracarus(
L= larvae; N=
nymphs;
lizards ( Gerrhonotus
Pellonyssus
Several
1
nr.) chalinolobus
M=
adult male;
female;
x=
by
removed
Clark
unknown#.
associated
multicarinatus).
stansburiana)
and
with
on
the
side- blotched
Santa Catalina Island.
lizard ( Uta
It attaches
injured
primarily under the folds of skin on the neck. Mammals
The
genus
often serve as host for this mite which can cause severe
Yunker ( 1956)
from
itching and dermatitis in humans ( Webb et al. 1983;
Bennett and Webb 1985). Unfed larvae may occur in
specimens were removed
described
specimens
adult
passeri
Allen' s Hummingbird ( Selasphorus
was
F=
Bay
from English
from
sasin).
an
Sparrows ( Passer
domesticus).
large numbers along coastal sagebrush- grassland
DERMANYSSIDAE
transitions during hot, humid summer months. Larvae
climb up the vegetation and attach to passing hosts upon
Dermanyssus
Larvae,
abandoned
which they feed on tissue fluids for several days. When
gallinae
from
engorged, the larvae drop from the host to the soil where
Hirunda
they develop into free- living nymphs. The adult stages
nymphs, and adults were recovered
nest material of a
barn
swallow (
are also free-living and, like the nymphs, prey on soil
rustica).
arthropods and their eggs.
TROMBICULIDAE
Eutrombicula
belkini ( California
Pest
This is
Euschoengastia
tia
Chigger)
one of the most common trombiculid mites
ambocalis
and
Euschoengas-
numerosa
Unfed larvae
of
these chigger mites were
recovered
DECEMBER,
1987
from
taken
from
of Lyonothamnus
Catalina Ironwood Tree,
after samples were put in modified Tullgren Funnels for
soil
groves
floribundas floribundus,
the
Additional
extraction of arthropods.
Peromyscus
1981
near
ambocalis
and
had been
that
maniculatus
alcohol since
two
and
maniculatus
R.
Wrenn
This
includes
humans,
California
north to
both
a
numerosa
was
species
is
Jay ( Aphelocoma
scrub
has
species
and
P.
including
of which occur on
Loomis ( 1974) from Ventura
and
several
including
It is found throughout
rodents,
Euschoengastia
from
County, California
coerulescens).
on
megalotis,
by
in
megalotis
rock
California
southern
preserved
Reithrodontomys
from San Diego, California.
that
evotis (
preserved in alcohol) from Toyon
Bay.
E.
Euschoengastia
outcropping.
described by Wrenn and Loomis( 1973)
a
was
described
Myotis
Acknowledgments
were obtained from the ears of three
ambocalis
trapped
specimens of
of
537
broad host
a
birds
of
and
Oregon
and
Montana,
University of California, Berkeley, for providing
additional records
of ticks
from
Santa Catalina
Island; Dr. Robert S. Lane, University of California,
Berkeley, for identifying tick specimens; Dr. William
J. Wrenn, University of North Dakota, for help
identifying trombiculid mites; Dr. James P. Webb,
Orange County Vector Control District, Garden
Grove, California, for assistance with the trombiculid,
macronyssid, and myobiid mite identifications; Ross
spectrum
and Kristi Turner, Catalina Island Marine Institute,
mammals,
Toyon Bay, Mr. Doug Propst and Terry Martin,
from
widespread
I am grateful to Professor Deane P. Furman,
southern
Texas
east to
Santa Catalina Island Conservancy, for providing
transportation and lodging while on the island;
Mexico.
Karen Haberman, Catalina Island Marine Institute,
described
Challet, Manager, Orange County Vector Control
District, for the use of laboratory facilities.
and south through
for her assistance in the field; and Mr. Gilbert L.
Kayella
lacerta
Originally
Euschoengastia lacerta
Kayella
genus
by
Brennan ( 1948)
by
as
and later transferred to the
Vcrcammen- Grandjean ( 1960).
As
the species name implies, the type series was obtained from a lizard, but since then it has been found
on a
including
of mammals,
variety
Spermophilus beecheyi)
the ground squirrel
on
REFERENCES
Bennett, S. G.
1977.
CrIED
Trombiculid Mites on Lizards
From Southeastern Arizona M.A. thesis, Dept. of
Biology, Calif. State Univ., Long Beach,
California, 192 pp.
Acomatacarus
This
arizonensis
trombiculid
southwestern
is
species
iguanid lizards in
on
exclusively
United States
from Santa Catalina
and
found
almost
and portions of
Mexico.
were removed
the
Specimens
from the iguanid,
Bennett, S. G. and J. P. Webb. 1985. A possible human
infestation
Acari:
by Eutrombicula belkini (
Trombiculidae)
in
Laguna
Gould)
Beach,
California Bull. Soc. Vector Ecol. 10(2): 118- 121.
Uta stansburiana.
Brennan, J. M.and M. L. Goff. 1977. Keys to the genera
Euschoengastoides (
A
from
single
a
appears
specimen
ground
nr.)
neotomae
of this
squirrel (
chigger
of chiggers of the western hemisphere ( Acarina:
was
removed
Spermophilus beecheyi.
be closely related to Euschoengastoides
Euschoengastoides hoplai. Additional
to
and
neotomae
specimens will
be
required
in
order to
properly
Trombiculidae).
J. Parasitol. 63( 3): 554- 566.
It
identify
this species.
Clark, G. M. and C. E. Yunker. 1956. A new genus and
species of Dermanyssidae ( Acarina: Mesostigmata) from the English Sparrow, with observations
on its life cycle. Proc. Helminth. Soc. Wash. 23( 2):
92- 101.
MYOBIIDAE
Pteracarus (
These
nr.)
mites
Vespertilionidae
and
Cooley, A. and G. M. Kohls. 1945. The genus Ixodes
chalinolobus
are
parasitic
on
bats
have been found
of the
throughout the
including California and Nevada.
described by Jameson and Chow (
discussed further by Dusbabek ( 1969
was
A
single
male
mite
was
removed
from
in North America. U.S. Pub. Hlth Serv., Nat. Inst.
Hith. Bull. 184: 1- 246.
The genus
world,
was
family
1952)
and
a
and
1973).
specimen
Dusbabek, F.
1969. Generic revision of the myobiid
mites( Acarina Myobiidae) parasitic on bats. Folia
Parasitol. ( Praha) 16: 1- 17.
DECEMBER, 1987
538
Dusbabek, F.
A
1973.
systematic review of
the genus
Myobiidae).
Acaro-
Pteracarus ( Acariformes:
logia, Tome XV, fasc. 2: 240- 288.
Evans, G. O.
W. M. Till.
and
1966.
pp.
Studies
on
the
British Dermanyssidae ( Acari: Mesostigmata) Part
II:
Bull, Brit. Mus. Natur. Hist.
Classification.
14( 5):
and
E. C. Loomis. 1984. The Ticks of
Bull. Calif. Insect
California ( Acari: Ixodida).
Survey
25: 1- 240.
Jameson, E. W., Jr.
a
new
Powder, W. A. and R. B. Loomis. 1962. A new species
of
records
new
and
from
Trombiculidae)
chiggers
reptiles
(
of
Acarina:
southern
California. J. Parasitol. 48(2): 204- 208.
1- 370.
Furman, D. P.
McDaniel, B. 1979. How to Know the Mites and Ticks.
Wm. C. Brown Co., Publ., Dubuque, Iowa, 335
and
genus
C. Y. Chow. 1952. Pteracarus,
myobiid
of
mites (
Acarina:
J.
1- 4.
P.
H.
Essai
1960.
de
classification des larves de Trombiculinae Ewing,
1944.
Myobiidae) from bats ( Mammalia• Chiroptera.
Parasitol. 38( 3):
Vercammen- Grandjean,
Acarologia 2(4): 469-471 ( chart).
Webb, J. P., R. B. Loomis, M. B. Madon, S. G. Bennett,
and
G. E. Green.
Eutrombicula
culidae)
1983.
The chigger species
Gould ( Acari: Trombi-
belkini
as a forensic tool in a homicide
investigation in Ventura County, California. Bull.
Krantz, G. W. 1978.
A Manual
of
Acarology, 2nd Ed.
Soc. Vector Ecol. 8( 2): 141- 146.
Oregon State Univ. Book Stores, Inc., Corvalis,
Oregon.
509 pp.
1987.
Wrenn, W. J.
Key to larval Euschoengastia
Acari: Trombiculidae) in North America. J. Med
Lane, R. S., S. E. Miller, and P. W. Collins. 1983. Ticks
Acari:
Argasidae
and
California Channel Islands.
Ixodidae)
from
Ent. 24( 2): 221- 228.
the
Pan Pac. Ent. 58( 2):
96- 104.
Wrenn, W. J. and R. B. Loomis. 1973. A new species
of
Euschoengastia
(
Acarina:
Trombiculidae)
from western North America, and the status of E.
Loomis, R. B.
1956.
The
chigger mites
of
Kansas
calfornica (
Ewing).
J. Med. Ent. 10( 1):
97- 100.
Acarina Trombiculidae). Univ. Kansas Sci. Bull.
37( 19):
1195- 1443.
Wrenn, W. J.
and
Euschoengastia
Loomis, It B.
1971.
The
genus
Euschoengastoides
Acarina: Trombiculidae) from North America J.
Parasitol. 57( 4): 689- 707.
Acarina
R. B.
Loomis.
radfordi
Trombiculidae)
1974.
species
from
The
complex
western North
America with descriptions of five new species.
Ann. Ent. Soc. Am. 67( 2): 241- 256.
BULL SOC. VECTOR ECOL, 12(2): 539-540
DECEMBER, 1987
THE INFLUENCE OF HOST BEHAVIOR ON SANDFLY ( LUTZOMYIA
LONGIPALPIS)
FEEDING SUCCESS ON LABORATORY MICE
R. E. Colemanl and J. D. Edmanl
Numerous
feeding
successfully
effect of
on
towards
and
Five-day old L. longipalpis were cold-anesthetized and
groups of 10, 20, 30, 40, 50, or 60 female flies placed in
Kale 1971)
holding cages without water or fructose. Experiments
Edman 1984, Klowden
commenced 48 hours later with the introduction of
and
so
and
either an unrestrained or a restrained BALB/c mouse
far been limited to the
We
report
laboratory
mice
on mosquitoes.
defensive behavior
of
(
using the technique
TABLE 1.
Host
Department
of
musculus)
into the holding cage. Experiments
light.
Restrained mice were anesthetized with
Nembutal and laid ventral surface down in the center of
( Lutz
of
Modi
and
Neiva)
and
Tesh ( 1983).
were
the cage. Remaining L. longipalpis were aspirated from
the cage after one hour and the number of blood-fed flies
Comparison of feeding success of Lutzomyia longipalpis on restrained
and unrestrained laboratory mice ( exposed for one hour).
Sandfly
Group
No.
Condition
Size
Restrained
0- 10
11- 20
21- 30
3
31- 40
0
41- 50
Unrestrained
Mus
were conducted early in the afternoon under fluorescent
sandflies.
Lutzomyia longipalpis
reared
host
from
Nondo 1982, Walker
and
Research has
defensive behavior
the
that
mosquitoes
shown
prevent
birds ( Edman
Day
Lea 1979, Waage
Edman 1986).
here
can
on
and small mammals (
and
have
studies
behavior
defensive"
of
Tests
Total
Blood
%
of
Flies
Fed
2
15
3
(
10
177
91
(
74
42
1
42
25
(
59. 52)
51- 60
1
55
26
(
47. 27)
Total
17
363
187
(
51. 51)
0- 10
2
17
0
(
0.00)
11- 20
10
175
2
(
1. 14)
21- 30
3
75
1
31- 40
2
75
0
41- 50
0
51- 60
0
Total
17
342
3
Entomology, University
of
Massachusetts, Amherst, MA
01003
Total
20.00)
51. 41)
(
(
56.75)
1. 33)
(
(
U.S. A.
0.00)
0.87)
DECEMBER, 1987
540
Each
recorded.
experiment was replicated
17 times.
REFERENCES
Cr1ED
Sandflies successfully fed on anesthetized mice,
but
were
1).
laboratory
feed
to
unable
TABLE
Day
and
mice were
highly
Anopheles
aegypti,
nigripalpis,
and
Culex
on
animals
Edman, J. D. and H. W. Kale II. 1971. Host behavior.
found that
Its influence on the feeding success of mosquitoes.
unrestrained
Edman ( 1984)
defensive towards Aedes
quinquefasciatus.
Unrestrained
from successfully feeding
We have found that unrestrained
mice prevented mosquitoes
in
most
instances.
mice were
equally
as
Culex
quadrimaculatus,
defensive towards L. longipalpis,
1984.
Mosquito
Day, J. F. and J. D. Edman.
engorgement on normally defensive hosts depends
on host activity patterns. J. Med. Entomol. 21: 732740.
allowing only a small portion of all flies to feed. This is
the
first demonstration that the blood
Diptera
other
defensive
than
mosquitoes
is
feeding
success of
affected
by
host
Klowden, M. J.
mosquitoes(
The
authors
at the
thank
Dr. R. B. Tesh for the
Yale Arbovinis Research
use of
Laboratory
for providing sandflies for the experiments. The
invaluable aid of Mr. G. B. Modi and Mr. Whei- kuo Wu
part
21
greatly appreciated. This work was supported in
NTH Biomedical Research Grants # RR07048-
by
and #
RR07048-20
1979.
Effect of
and
Endowment Fund Grant.
by
a
Diptera: Culicidae). J. Med. Entomol.
15: 514- 517.
and
was
A. 0. Lea.
feeding success of natural populations of
responses.
Acknowledgements
facilities
and
defensive host behavior on the blood meal size and
Joseph P.
Healy
Modi, G. B. and R. B. Tesh. 1983. A simple technique
for mass rearing Lutzomyia longipalpis
and
Phlebotomus
papatasi (
Diptera: Psychodidae) in
the laboratory. J. Med. Entomol. 20: 568-569.
Waage, J. K. and J. Nondo.
1982. Host behavior and
mosquito feeding success: an experimental study.
Trans. Roy. Soc. Trop. Med. Hyg. 76: 119- 122.
Walker, E. D.
and
J. D. Edman.
1986.
Influence of
defensive behavior of eastern chipmunks and grey
squirrels ( Rodentia: Sciuridae) on feeding success
of
Aedes triseriatus ( Diptera: Culicidae). J. Med.
Entomol. 23: 1- 10.
DECEMBER, 1987
MALARIA TRANSMISSION IN THREE STYES SURROUNDING
THE AREA OF BOBO-DIOULASSO ( BURKINA FASO):
THE SAVANNA, A RICE MELD, AND THE CITY'
V. Robert2.3, P. Gazing, and P. Camevale2
Malaria is
Africa. At the
to
90
percent of
Gazin,
disease in West
increased.
rainy season in rural areas, 70
the children have parasites in their blood
maximum
an endemic
1985).
et al.
The
frequently
most
is Plasmodium falciparum,
parasite
Plasmodium
malariae,
and
Significant litres
ovale.
of
Gazin
one
Three
the
and
to
area
in Bobo- Dioulasso
observed
found in
there
endemic,
intensity
the
from
transmission
are
assay,
Therefore,
each
inhabitant
was
Seventy-three percent of An. gambiae s.l. and 77
as
percent of An. funestus were parous, indicating high
all
daily survival rate. Thus, a proportion of 21 percent of
rhythm
another, as
its
and
large
are
have
we
neighbourhood.
located 60 km
north of
(
Coz et al. 1961).
the
of
sites were studied:
a traditional village,
s. l. reached its
the adults would reach the age for malaria transmission
is
malaria
differences in
antibodies,
gambiae
theoretically bitten by 7,500 Anopheles spp. per year.
1984).
et al.
Although
man/ night).
the remainder are
malaria
Anopheles
in August ( 25 bites/ man/ night), while An.
funestus reached its maximum in October ( 30 bites/
observed
rarely Plasmodium
very
by immunofluorescence
assessed
adults (
parasitic
end of the
Bobo-
Sporozoites were observed in the salivary glands of
two species from May to December.
The
sporozoite index was 3 percent after 3,000 dissections.
these
Thus, every inhabitant was theoretically bitten by 135
infected Anopheles spp. per year.
Dioulasso near a ephemeral marsh land.
a
located in
village
developed
rice
where rice
is harvested twice
the
urban
fields, 30 km
without
et al.
The
the
all night catches on
Anopheles
periand
supply
over
30
identified
were
fauna
The main malaria vector was An. gambiae
s. l.,
while An. funestus was less represented. The vectorial
density was higher than in the savanna area. Anopheles
gambiae s.l. was present all year long with large seasonal variations according to agricultural activity. Due
to the rice cultivation in the dry season, the density
reached more than 40 bites/man/night. During the rainy
by
season rice cultivation, the density reached 80 bites/
human beings.
Caught
man/night. Anopheles funestus was present only from
dissected for
classical
and
examination of ovaries and of
The village in the rice field.
collection
1986).
anthrophilic anopheline
usual
a
distribution
district, built
years ago and with a minimum water
1985).
et al.
including
water
collection system, and a central
Robert
recently
Bobo- Dioulasso,
Robert
a year(
any
of
middle
Bobo-Dioulasso,
of
city
district
the
north of
salivary
was studied
glands.
September to December with a maximum of 6 bites/
man/ night In these conditions, every inhabitant was
theoretically bitten 14,000 times per year by Anopheles
RESULTS
spp.
It has to be underlined that the anthropophilic An.
The traditional
Anopheles
funestus
season,
but
at a
January
and
sensu
savanna.
lato
and
gambiae
Anopheles
Anopheles
nili
was
low level.
gambiae
When the
s. l.
rains
began to
s.l. population was mainly composed of
nulliparous
high
and/ or
females ( 55%)
daily
indicating dispersion was
Only 1. 9
survival rate was short.
percent of the adults could reach the age suitable for
February, during the cold, dry
Anopheles spp. were seen ( Fig. 1).
From
March, An.
night).
gambiae
in the
were predominant, while
also noticed
In
village
emerge(
began, the
malaria transmission. The An.funestus population was
older with a parous rate of 73 percent. Such a high
5 bites/ man/
nulliparous rate of An. gambiae s. 1. was one of the
density
explanations for the surprisingly low sporozoite index
anopheline
Presented at the 1st European Branch Meeting, SOVE, Montpellier, FRANCE, 11- 12 September, 1986.
2ORSTOM - IFRSDC, B.P. 171, Bobo-Dioulasso, BURKINA FASO.
3Present Address:
19 Bd de Port-Royal, 75013 Paris, FRANCE.
BULL SOC. VECPDR ECOL
542
bites/man/night
ma =
90
DECEMBER, 1987
Rice Field
80 —
1--- _..\
Savanna
70 —
Downtown
60 —
50 —
40-
p•
20 —
10 —
f
0
10. 0 —
1. 0
h=
I
I
1
F
•
•
=/
I
I
I
M
A
M
I
1
I
J
J
A
S
O
N
D
infective bites/ man/ night
—
I.••
1
l
l:
0. 1 —
1
C
C
o
Y
r
J
Figure 1.
fig-
I
0.001 —
F
M
A
M
J
J
A
1
S
ON
D
Annual variations of anopheline man-biting rate ( ma) and of malaria inoculation rate ( h) in
three
sites
surrounding the
area of
Bobo-Dioulasso, Burkina Faso.
DECEMBER,
1987
of this species (
In
these
0.5%
after
conditions,
8,000 dissections).
malaria
regularly use bed nets. Malaria transmission may have
transmission
was
by two factors: ( 1) it occurred in two
during May and June then September to
characterized
periods
November,
and (
2) the yearly inoculation
543
rate was
50
infected bites/ man.
been reduced for this population for these reasons.
Moreover, we have observed that the childhood
parasitological index followed the same pattern of the
inoculation rates and decreased from the savanna to the
urban area(
Gazin
et al.
1987). It is evident that malaria
infection can vary considerably within a small area of
The
Africa.
area.
urban
In the
district, Anopheles
peri- urban
spp. were
high density
from July to November only, with a
in August ( 50 bites/ man/ night). Every inhabitant
present
theoretically bitten 2, 500 times by Anopheles
98
and
Anopheles
percent of these
were
An.
per year
gambiae
s. l.
Parous
rate was
after 500 dissections).
Every
inhabitant was in theory bitten by 4. 6 infected
Anopheles spp. per year.
In the center of the city, Culex quinquefasciatus
was the major nuisance, with 25,000 bites/ man/year.
Anopheles sl, p.
s. l. were caught
We
at
were
very
with
estimated the
Coz, J., H. Gnichet, G. Chauvet,
a
only A. gambiae
75 bites/ man/ year.
rare and
density
number
0. 15, corresponding
of
of
infected bites/ man/ year
to one
infected bite every 7
CONCLUSION
1.
1984.
Etude parasitologique et serologique du
paludisme dans la region de Bobo-Dioulasso.
OCCGE-Inf. 92: 5- 14.
Gazin, P., V. Robert, and P. Carnevale. 1985. Etude
longitudinale des indices paludologiques de deux
villages de la region de Bobo-Dioulasso ( Burkina
Faso).
Ann. Soc. Beige Med. Trop. 65(supl. 2):
Gazin, P., V. Robert,
Great differences
appeared
in the
intensity
the rhythm of malaria transmission in three sites
within short distances.
The highest Anopheles spp. density was
in the rice field, while the highest transmission
savanna.
In the
50 times lower
was
1%
Gazin, P., L. Ovazza, O. Brandicourt, and P. Carnevale.
paludisme
of the
M. Coz.
181- 186.
years.
in the
and
Estimation du taux de survie chez les Anopheles.
Bull. Soc. Path. Exot. 54( 6): 1353- 1358.
low ( 43%) and also so was the
0. 19%
sporozoite rate (
REFERENCES CITED
was
city it
than
peri- urban
in the
and
in
located
observed
occurred
district, transmission
savanna, and
in the
center
1, 000 times lower.
was
indices
urbain
and
P. Carnevale.
a Bobo-Dioulasso.
parasitologiques.
1987.
Le
2.
Les
Cahiers ORSTOM, Ser.
Entomol. Med. Parasitol. 25( 2): ( In Press).
Robert, V.,
P. Gazin, C. Boudin, J.- F. Molez, V.
Ouedraogo,
and
P. Carnevale.
1985.
La trans-
mission du paludisme en zone de savane arbor a et
en zone rizicole des environs de Bobo-Dioulasso.
Ann. Soc. Beige Med. Trop. 65(supl. 2): 201- 214.
In this region nobody is free from the risk of getting
infected,
their
even
for the city inhabitants
frequent journeys
Nuisance
Culicidae
in
in the
rice
quinquefasciatur)
and
has
large
encouraged a
city ( Culex
Robert, V., P. Garin, V. Ouedraogo, and P. Carnevale.
1986. Le paludisme urbain a Bobo-Dioulasso. 1.
Etude entomologique de la transmission. Cahiers
field( Anopheles spp.)
ORSTOM, Serie Entomol. Med. Paiasitol. 24(2):
when
considering
to rural areas.
the
proportion of the population to
121- 128.
DECEMBER,
1987
CONTRIBUTIONS TO THE ECOLOGY OF TAHYNA VIRUS
IN CENTRAL EUROPE'
J. Pilaski2
ABSTRACT: Tahyna( TAH) virus is a mosquito-borne virus which is present in Eurasia where it causes a febrile
illness in humans, especially in children. The virus is transmitted transovarially in mosquitoes of the genus Aedes.
The most important vectors are Aedes vexans and Aedes caspius. The virus could be isolated in 1981 from these
two species at the eastern shore of Lake Neusiedl in Austria( Ae. caspius) and at an inundation forest at the Upper
Rhine in Germany( Ae. vexans). The role of some ecological factors ( air and water temperature, time of inundation
process, salt content of the water) which influence the persistence of the virus within a natural focus is discussed.
RESUME: Tahyna( TAH) virus est un virus moustique-ne qui est present en Eurasie on it cause une maladie febrile
dans les hommes, surtout dans les enfants. Le virus est transmit transovariellement dans les moustiques du genre
Aedes. Les vecteurs les plus importants sont Aedes vexans et Aedes caspius. En 1981 it etait possible d' isoler le
virus de ces deux especes stir la rive d' est de l' etang de Neusiedl en Autriche ( Ae. caspius) et dans une foret
d' inondation de la
partie superieur
du
cours
du Rhin
en
Allemagne ( Ae.
vexans).
Le role de quelques facteurs
ecologiques( la temperature de l' air et de l' eau, le temps de l' evenement de l' inondation, la teneur en sel dans l' eau)
qui influencent la persistance du virus dans le foyer naturel, est discute.
Das Tahyna ( TAH) - Virus ist ein durnh Stechmucken iibertragenes Virus, welches in
FASSUNG:
ZUSAMMP
Eurasien verbreitet ist and dort fieberhafte Erkrankungen bei Menschen, vor allem bei Kindem, hervornuft. Das
Virus wird transovariell in Miicken der Gattung Aedes ubertragen. Die wichtigsten Vektoren sind Aedes vexans
and Aedes caspius. Im Jahre 1981 gelang die Vi usisolierung aus diesen beiden Stechmuckenarten im Bereich des
Ostufers des Neusiedler Sees in Osterreich( Ae.
caspius)
and
im Oberrheingebiet in Deutschland( Ae.
vexans).
Die
Rolle einiger okologischer Faktoren ( Umgebungs- and Wassertemperatur, Zeitpunkt der Uberschwemmungen,
Salzgehalt des Wassers), welche die Persistenz des Virus innerhalb eines Naturherdes beeinflussen, wird diskutiert
system illness in children living in Czechoslovakia have
been caused by a TAH virus infection.
INTRODUCTION
Isolation history and clinical symptoms:
Tahyna( TAH)
Aedes
vexans
Bardos
and
virus was
Aedes
and
pathogenic
cases caused
by
of
Bardos
and the
the
monia
by
by
family
et al.
Bunyaviridae(
et al. (
febrile illness
and
Union
clinical
et al.
1972).
The
illness in
influenza-like
southern one in Tajikistan, in the south of the Soviet
et al.
1980), in France( Hannoun
et al.
children
symptoms.
has been found only in
Bardos
Bishop
adults.
1980) that every
every fifth case
is
characterized
Bronchopneu-
at a
latitude
of
37° ( Daniyarov
et al.
1974).
In
Germany, the presence of the virus was demonstrated in
1968 and 1969 by direct isolation from Ae. vexans
have been found in Czecho-
Soviet Union ( Lvov
the
69° of northern latitude( Traavik et al. 1978), the most
encepha-
Human
for humans.
the virus
clinical picture of
mainly
in Eurasia( Fig. 1), the most northern one in Finland at
It belongs to the California
litis subgroup
1980) and is
1969),
southeastern part of
mosquitoes
caspius
Danielova( 1959) in the
Czechoslovakia.
slovakia(
by
Virus distribution in Eurasia:
To date, at least 15 natural foci of TAH virus exist
isolated first in 1958 from
mosquitoes in the Upper Main region near Baunach
(
Spieckermann
and
Ackerman 1972). The presence of
an additional natural focus was postulated in the Upper
seventieth case of
Rhine area near Worms on the basis of a seroconversion
of a sentinel rabbit in
1969 ( Spieckermann and
of central nervous
Ackemmann
It has been
shown
1974).
Presented at the 1st European Branch Meeting, SOVE, Montpellier, FRANCE, 11- 12 September, 1986.
2Medizinisches Institut fir Umwelthygiene, Universitht Dusseldorf, 4000 Dusseldorf, FEDERAL REPUBLIC OF
GERMANY.
DECEMBER,
1987
70 °
n.
545
47
lat.
65
60
47
-
5545
30 _
5
34.
1
I
18------
23
_
35—
22
10-
20
8— _
6
5
217—
451
21
38. _
7
r_
27.
40
16
32
25• ?
mow ?
ammo?
35
7Q--}--- rte
Figure 1.
,
J ,
J '
A
'
S
'
0
'
N ,
D
Seasonal distribution of Tahyna virus records in Eurasia between the 35th and the 70th latitude, compiled
on the basis of literature statements. The study periods are marked by thin lines, the virus records by thick
lines. The range between the 47th and the 48th latitude was extended without any respect to a correct
scale ( Pilaski and Mackenstein, 1985).
Mosquito
In
circadian
order
rhythm,
mosquitoes were caught
net over
24 hours
29
30 August, 1980.
and
rainfall (
Virus isolation
In
order to
using
Fig.
dead
Moncadskij
forests, which are inundated several times in the
a
humidity
of the
2).
year by floods from the Rhine river( Fig. 4).
C. Upper Main
area (
north of Bamberg, near
Baunach): flat meadows and wooded slopes within
the Main Valley, where inundations had occurred
during the last years.
studies -
become
Gennersheim- Bingen):
Rhine branches surrounded by meadows and
several peaks which were
the relative
area (
the circadian
focus near Baunach on
The mosquito ( 90% Ae.
activity here had
influenced by light intensity,
by
with
at the natural
vexans)
air, and
B. Upper Rhine
rhythm:
to become acquainted
1980 and 1981:
acquainted with the ecological
conditions within various mosquito
habitats, especially
in the
natural TAH vines foci during two seasons, in
1980( January 2 to September 12) and 1981 ( August 17
to September 10), the following six different regions in
Germany, the Netherlands, Austria, and Italy were
visited ( Fig. 3).
D. Lake Neusiedl ( eastern shore) in Austria steppe
and meadow biotopes with multiple shallow lakes
and marshes ( Fig. 5).
E. Isonzo River Delta in Northern
Italy: corn fields
and meadows with partially dry ditches and with
groves along the branches of the Isonzo River
Delta.
A. Lower Rhine
hibernating
marshy;
collected.
area( various sites):
females;
rainwater
mixed
basins
old cellars with
forests,
where
partially
larvae
were
F. Amper Moos (
west of
Munich):
meadows and
forests on the eastern bank of the small river
Amper.
A
total
species
45,705
of
1 out
148
of
caught
Since virus isolation from mosquitoes during one
mosquitoes
season is often limited to only a few days, it is not
pools), caught at the eastern shore of
Lake
possible from the limited data to answer the question
August 18, 1981. Five TAH
virus
whether the virus is still circulating within the natural
6,066 individuals)
focus at the Isonzo River Delta ( Mackenstein and
Pilasld 1982; Pilasld and Mackenstein 1983, 1985).
from Ae.
one
on
derived from 62
in
the Upper Rhine area( near
identified Ae.
on
isolates from
and
Antibody prevalence in humans in the Rhine
from
three
area:
mosquitoes.
unidentified
No TAH
in the Upper Main
Between October 17, 1985 and June 1, 1986, a total
in the
is
that this
natural
Since the
area
had been
the meadows
could
strains
virus
mosquitoes captured
focus in
TAH
Germersheim)
of two
mosquitoes
vexans
six
caspius
pools (
September 10, 1981, consisting
obvious
the virus still exists there.
virus
Neusiedl( Austria)
isolates
virus strain from an Ae. caspius pool in 1981 shows that
The
seasons.
in TABLE 1. Altogether
isolated,
strains were
these two
25
to
belonging
mosquitoes
during
caught
was
results are given
of
DECEMBER, 1987
546
focus
near
summer
an
of 1, 563 sera from hospitalized persons was collected
Baunach
for a serological survey in the Rhine area between
inundations
1978, it
stopped since
longer
no
be isolated from
Boppard in the north and Breicach in the south. TAH
seems
important TAH
virus antibody titers were estimated by employing the
indirect immunofluorescence assay ( IFA) using TAH
vines
Germany
Also,
on
the
eastern
Austria the
ecological
1965
when
Aspock
virus
there.
shore of
conditions
virus infected Vero B5 cells. As shown in Figure 6, the
highest percentage( 23%) of positive sera was found in
patients in the hospital of Germersheim near the Insel
Griin, one of the major inundation forests in the Rhine
Lake Neusiedl in
have
changed since
Kunz ( 1967) had isolated the
and
Nevertheless, the isolation
of one
TAH
area.
I.
Y
1u.
111
.
350000
171,
115000
1
v
INI
I
L—
t
16
e
U I I L_ J L___
L1
I
1
I
2(21.
100
MO:
woo
90
77000
11000
00
5500
70
7000
1400
60
350
40
j
11
1
18,.
1
1
11
1 15 i.
66
1
v y11•
1, %
1,
170,
16;.
22 ;
A ice'•
1
A
i.
1171,
116
i.
1
n
1.
30
X13 i, .
1. , 0,,
20
1, 6
1121.
10
0. 35
0, 17
1111,
0
1
1
175
50
i 1
1.
1701:
1 19 1.
I
5,5
111,
100.
1.
0. 08 1101_
J
9f.
i1\
i
7l
a
11 O 3EZ
E1: u.
70.
N.
E
it
S0.
1
w.
catching
site
31 °
IMainauel
n,
i 71.
u.
JJJ
0
17
11
19
70
71
77
73
79. 01. 5.
Figure 2.
76
1
7
3
6
5
6
7
1
9
10
11
17
13
16
15 %
17
11
n IEL
30. 01. 10.
Circadian rhythm of mosquito activity between August 29 and 30, 1980, in the natural focus near
Baunach.
DECEMBER, 1987
547
TABLE 1. Mosquitoes captured from January 2, 1980 to September 10, 1981, in Central Europe( Germany,
Austria, and Italy) and isolated Tahyna virus strains.
o
1
o
ON
ON
0000
a
2-
00
2
00
1
r
Species
O
M
CV
.`
a
N
n/%
n/%
n/%
0
00
VI
00
U
n/%
n/%
n/%
2511/ 91
4/ 1
i'
n/%
la.4
K
n/%
Aedes
31/ 1
annulipes
299/ 10
cantons
caspius
3/< 1
28/< 1
3/< 1
41< 1
219/ 31
11/< 1
2/< 1
129/ 2
2/< 1
cataphylla
321/ 11
cinereus
6/< 1
communis
7/ 1
3/ 3
112/ 5
46/ 7
5/ 5
249/ 11
23/ 1
567/ 91
88/ 84
1827/ 832
24/< 1
darsalia
1/< 1
3/< 1
excrucians
flavescens
7/< 1
geniculatus
1/< 1
7/< 1
42/ 1
punctor
refill
4/< 1
1/<
1
1
rossicus
1/<
sticticus
22/ 1
vexais
10/< 1
73/ 2
51< 1
2/< 1
321/ 7
410/ 6
113/ 1
4083/ 91
5877/ 90
1186/ 14
claviger
2/< 1
2/< 1
maculipennis
2/< 1
38/ 1
Anopheles
71< 1
plumbeus
3/< 1
849/ 10
1/<
1
1/< 1
2/< 1
1/ 1
2/ 2
2/< 1
Culex
264/ 31
724/ 9
modestus
2057/ 72
pipiens
1/<
1
12/< 1
territans
26/ 1
146/ 5
5/ 5
6/< 1
species
42/< 1
Culiseta
34/< 1
auudata
11/< 1
1/<
subochrea
912/ 11
2/< 1
1
Mansonia
richiardii
27/ 1
Ident. Females.
2859/ 100
Unident. Fern.
Total Females
4511/ 100
700
2859
195
Total Males
Unident. Mosq.
Ttl. Mosquitoes
3054
5211
1706/ 20
17/ 1
6506/ 100
8417/ 100
2744/ 100
693
7199
672
9089
1825
4
2748
4244
6119
9901
150
5361
7199
15158
TAH Virus Str.
MIR
1
0. 07
n= Number
Percentage of identified females
MIR= Minimum infection rate per 1000 mosquitoes.
1, 2=
Number
of
isolated TAH
virus strains.
1034
625/ 100
104/ 100
2211/ 100
625
31
104
4452
2241 1
7
19
1595 2
656
111
6066
5
0. 82
DECEMBER, 1987
BULL SOC. VECIOR ECOL
548
Ecological factors
TAH
and
dates
is
virus persistence:
preceding
Comparing
virus isolations in Europe, it became
the
of
successful
TAH
obvious
that a
required.
The optimal temperature range is 28 to
30°C. This explains why Ae. vexans appears rather late
during the year ( Mohrig 1969; 158).
inundation
The center of the TAH virus distribution in Europe
occurring 40 to 50 days before mosquito
catching am important ecological factors ( Mackenstein
1984).
lies within the Pannonian low plain. For this region a
temperature
water
16° C
above
an
and
process
These
in 1981. There
Rhine
area
water
level
during
increased
of
of
last
the
the
during
August
Rhine
the last
week of
July
process
Bechtle( 1979), the origin of the high salt content of the
water temperature
and the
first
soil in this area are the sediments of the tertiary sea
week
In addition to Ae. vexans, another important vector
dropped slowly until the end of
Thus, these dates fit into the above
Oviposition
of TAH virus in Europe is Ae. caspius, a mosquito of
salt or
by Ae.
at the water surface
the
river
seasonally. The
after a
The
scheme.
mentioned
of
inundation
after an
Hungary and Yugoslavia. For instance, the TAH virus
focus in northern Yugoslavia described by Gligic and
Adamovic( 1976) lies within this region. According to
in the
drop
and
September.
mud
was a significant
July.
week of
extends from Austria over southern Czechoslovakia to
found in the
were
conditions
ecological
certain salt steppe or puszta is characteristic, which
dry
but
a water temperature
development
water (
Mohrig
1969).
This mosquito
on the edge of slopes and the
water meadows. Asptick and Kunz ( 1967) have found
bed
inundations
where
rate of the
occur
that TAH virus has been present in the steppe regions at
larvae is increased
the eastern shore of Lake Neusiedl in Austria in Ae.
It has been demonstrated
experimental conditions
brackish
species is responsible for the TAH virus cycle in the salt
hatching
season.
females takes
place not
vexans
that
Ae.
between 14
larvae hatch
vexans
and
caspiur with high infection rates. The presence of TAH
under
virus in two different ecological regions has been well
at
16° C. For further
a water temperature of at
least 16
to
documented
17° C
in Austria, i.e., the puszta near Lake
Neusiedl and the inundation forests of the Danube river
0
s0
t_
Frankfurt
C
F®sMunchen
Wien
Do
Q
Figure 3.
200Km
E
Trieste
Geographical position of the six regions( A-F 0) which had been studied in the time between September
4, 1979,
and
September 10, 1981.
DECEMBER, 1987
BULL SOC VECIOR ECOL
N
Do
1
km
0A
0"-----,--"•...
114• 1••••
IMPoolIor " Ail
NO , ^
Ili
1111110.„
t-
foist
Bell-
It
heim
‘
Inset Grun
IIII
II
i
72-
••••
lb. ,
25/ 1981-
„
a.._ , ,, ,,
a _
74._N.
Ilt
V
1111. • ‘%*
A110.
allialsr
F stat
It
,
n
.-.
•-
n
n
n
13- mm
A• 16.- 41/
Lingenfeld
549
,
•
„
„
7
—... :
1- :_,....
01111111111111111111111111111110",-,
41.
1
41111111111111r
qi, •••--
o_ is,
IN11111,
if•r ANN
411. 1111r)
411111111
41111111111r ,,
4111111P: ,
2/
1980
-
•
41111W„
AIIII
24/ 1980
t-•••t\ -
1111. 11111
NM%
11• 11111
1%o
A
A
A
A
A
A
A
A
A
A
A
A
A
A
4111111111r
S'
1411111d5h,
n-
Ilielhar
8"
L
ilk
to ' „...„,
1101:.
#
n
Figure 4.
n
n
n
n
n
n
1 NAN
f M9
Germersheim
Map of the study region ( b) within the Insel Gran near Germersheim in the Upper Rhine area.
n
7
N
a••••
4777
1 .
I.:
er,„.....
am
a,
.
0
47 Or
1
2
3
4
A
0
r....;__-!...
r;
5 krn
CD
si Andra
Ill,I• .
11. 11. .
OM
Onse• 11/
siedler 4,. -:
Oa _
Ire.
-
ft?
1.
4.-
Illmitt
ar
1.--
.
A.
4
4iften
5
13
u
9
7
V, ,,
g_ ti,
2.
--
I
7,-
16
lie
S...
AIM! dna • ..
Oh
e
--.-
IP
OM
1
Vit.
-- -- -'
1•••...
II
IN•
IMMO
101
I
• •
1
s
II,
,..., ~
Alkiii .
101•
1•
1•
M.
1101•
Itn ....-.......
11111•
41 1 1,
A*. m.....-
la
Iv
Figure 5.
Map
illirP••
111• 91f1
1r:
6.
of the
study
region (
D)
lir
Ag
rsagt•
at the eastern shore of
Lake Neusiedl, Austria
01
m...._
BULL SOC. VECIDR ECOL
550
Fischamend ( Aspock
near
Aspbck
et al.
1970).
different TAH
cycle within
virus
The
Kunz
and
1966,
1967;
species.
question arises whether two
cycles
the inundation
exist
forest,
Ae.
Ae.
caspius
The
question whether a virus transport takes place
from
reservoir.
longer
of
interest
be transmitted
cycle
since
is
of a greater relevance
it is
to
transmit
viruses
This opinion was in accordance with the
revolution when Watts et al. ( 1973) found transovarial
transmission of LaCrosse virus in Aedes triseriatus. In
is
the following years transovarial transmission in
mosquitoes has been well-documented for many
no
now clear that the virus can
transovarially
able
meaning of the whole scientific world. It was a kind of
as the main vector.
one cycle to the other or whether the steppe or the
inundation forest
not
Peus ( 1966) stated that a virus cannot
arrange itself with a mosquito in order to form a virus
the main vector, and the cycle within the steppe region,
with
are
transovarially.
is
vexans
For many decades it had been assumed that
mosquitoes
in Europe, i.e., the
where
DECEMBER, 1987
within
one
mosquito
arboviruses (
0
Rosen, 1981).
50
It has also been shown for
100km
I
I
9°/ 01
Boppard
St. Goar
Eltville ( 11%)
3% 1
I
ngetheim (
18°/ a)
'
Gross- Gerau(
6o/°)
Kuhkopf
Alzey
•
6%)
Inset Gr un
Germershet m
23%)
Rastatt ( 11°/°)
7%)
Ereisach
Figure 6.
Prevalence of TAH virus IF antibodies in 1, 563 sera of patients admitted to 9 hospitals in the Rhine area.
The two
major
inundation forests, Inset Grun
and
Kuhkopf,
are
indicated ( Neihaus, 1986).
DECEMBER,
1987
BULL SOC. VECIOR ECOL
TAH
virus by Danielova and Ryba ( 1979).
We have been interested in the ecological factors
which are responsible for a successful transovarial
TAH
transmission of
virus.
shown that neural variants of
for
By
passed strains.
experiments
laboratory reared Ae.
than
mosquito
using
for
passed strains
extraneurally
of
in the
propagation
Danielova ( 1968) had
TAH virus are less suited
an
vexans
poorly in
hamster
in the
infection
producing
TAH
virus
viremia
in the
correlates with enhanced
mosquito ( Pilasld and
During
found
mosquitoes, we
strain
the mosquito and that selection of
variant ( or population)
or
neuroadapted and
artificial
some evidence that a neuroadapted
replicates
extraneurally
ability to
Nelles 1983).
mouse
replicate
551
820 l S/cm ( TABLE 2).
In this table, also a recultivated brown coal mine
near Most is included, which does not belong to any of
the two mentioned virus cycles, i.e., the inundation
forest( Ae. vexans) and the steppe cycle( Ae. caspius).
Czechoslovakian scientists isolated TAH virus in June
and July 1982 from the two mosquito species Ae.
cantons and Ae. dorsalis. This was a surprise as virus
isolation from Ae. vexans was not successful( Malkova
et al.
1984).
mineral
In the surrounding area of Most many
springs
exist.
A water sample taken on
September 5, 1983, from a shallow pond in this region
revealed a conductivity of 47,000 µ S.
A similar sample taken from a little soda pan at the
mosquito catching activity in September
found the Greater Duckweed ( Spirodela
eastern shore of Lake Neusiedl near Frauenkirehen on
covering the surface of small water ponds in
the inundation wood at the isle Gdin. Visiting the same
Thus, it may be tentatively postulated that the
1981,
we
polyrrhiza)
September 13
area on
little
that this
because the
10 to 30
plant
14, 1982, it
formed
plant
water
and
in inundation
the
study
1983.
of
TAH
virus
where
from Ae.
Danielova
Pott ( 1980) demonstrated
parameters
polyrrhiza
plant
of
(
was also
found in
is
and
of the drying process. This may lead to an increase of
the salt content and to a reduction of living space for
in
each mosquito larva. It has been shown that mosquito
foci in Europe
TABLE 2.
Date
mosquitoes; and
Dmholec in September
larvae
by estimating
environmental stress" have a higher rate of virus
infection than others, which live under optimal
a
Water
revealed a
several
growing up
under conditions
of an
Spirodeletum
well-documented
ecological conditions ( Novak et al. 1986).
Beaty et al. ( 1977) have demonstrated increased
by
hemagglutination activity for several viruses of the
that
characterized
pS/ cm.
ponds had a rather low water level. It is obvious that
in the Vojvodina in
water
480 to 650
north of
Spieckermann
Adamovic ( 1976) had
small water ponds and creeks at
natural
and the lack of further inundations during the weeks
before our stay at the isle Griin, all water holes and
under these conditions many holes dry out The amount
chemistry
Kehldorfer 1915) is
community
range of
Due to a low rainfall, a rather high air temperature,
a characteristic
of water inside a small pond is reduced in consequence
vexans
near
within a natural focus.
the existence of a
virus;
and
is an important ecological factor for the TAH virus cycle
and
postulated
Gligic
where
area of
it
woods since
Ackerman ( 1974) had
isolated TAH
carpet
conductivity of the water where mosquito larvae hatch
was
i.e., inside the isle Kiihkopf
isle Griin in October 1982,
focus
vegetation
time. It seems to be
cm at this
Yugoslavia,
large
level inside the inundation forest
other similar areas,
natural
a
was recognized
August 27, 1983, revealed a conductivity of 26,000 MS.
a
conductivity
from
samples taken
different TAH
conductivity
of
virus
520
to
family Bunyaviridae due to high salt concentrations in
the
diluent.
The physicochemical mechanism
responsible for this phenomenon is not known. It is also
Conductivity of water samples taken in several natural TAH virus foci in Europe.
Country
Locality
Conductivity ( pS)
13./ 14. 09. 82
Germany
Isle Griin ( River Rhine)
600- 790
01. 10.82
Germany
Isle Kiihkopf ( River Rhine)
520- 630
09. 08. 82
Yugoslavia
Vojvodina ( River Tisa)
820
01. 09.83
Czechoslovakia
Near Dmholec
520
05. 09.83
Czechoslovakia
Recultivated Brown Coal Mine
620
DECEMBER, 1987
552
for the
this
whether
unknown
geographical
for
of these viruses
mechanism
distribution
may be
and the
responsible
pathogenicity
mammals.
Daniyarov, O. A., A. T. P. Pak, M. A. Kostyuk, V. P.
Bulyrev, T. M. Skortsova, L. L. Berezina, N. G.
Kondrashina, V. L. Gromashewski, and D. K.
Isolation of Tahyna virus from
1974.
Lvov.
mosquitoes in the settlement of Lower Pyandzh.
Southern Tajikistan. Ekol. Virusov. 2: 126- 129.
CITED
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aus
Stechmiicken in
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Gligic, A.
Z. R. Adamovic.
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hyrcanus
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Tahyna Virus
Malkova, D., J. Holubova, Z. Marhoul, U. Cerny, Z.
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Mohrig, W.
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Chumakov, S. Ya. Gaidamovich, C. Hannoun, D.
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Hajkov,
Bishop,
Stechmiicken
Der Neusiedler See in Farbe.
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Francksche
1984. Zum Vorkommen des Tahyna-
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1981.
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Dusseldorf.
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Mackenstein, H
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various organs of the
Aedes
vexans
mosquito.
Fol.
Niehaus, H.
1986.
Bevolkerung
Danielova, V.
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demonstration
J.
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1979.
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Laboratory
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Tahyna virus in Aedes vexans and the role of this
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Novak, R. J.
on
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Peus, F.
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1966.
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Information Exchange ( Atlanta/ USA) ( 44):
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Spieckermann,
126.
D.
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Ackermann.
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Hyg.,
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1985.
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Orig.
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and
Tahyna
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the neural
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isolated
from
mosquitoes in Southern and Arctic Norway. Acta
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Watts, D. M., S. Pantuwatana, G. R. de Foliart, T.
M.
Pott, R.
1980.
eutropher
Die Wasser-
and
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H.
Thompson.
1973.
Transovarial transmission of LaCrosse virus in the
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Science 182: 1140-
BULL. SOC. VECTOR ECOL., 12( 2): 554- 560
DECEMBER, 1987
ESSAIS DE MODELISATION DE L'INGESTION
DES PARTICULES PAR LES LARVES DU COMPLEXE
SIMULIUM DAMNOSUM ( DIPTERA, SIMULIIDAE) 1
P. Elsen2
ABSTRACT: In the chemical control of simuliid larvae, the dosage of insecticide to be applied is empirically
calculated without taking into account the alimentary behaviour of the larvae and different combinations of river
section and speed of current giving equal flows, which causes the passage of different quantities of insecticide per
unit of river section and time. The author presents a new formula to calculate the quantity of insecticide to be
applied. The latter is based on the river section, the lethal dose of the product used, the number of particles per
unit of weight of the product, and on the speed of intake of particles by the larvae which is calculated as a
function of temperature, flux of natural particles in suspension in the river water, and the particle size and
relative quantities; the whole of this depending on the species considered. Applying experimental values to this
model, for a given species, quantities of insecticide to be applied must be multiplied by a factor up to 1. 8 when
the river section is doubled and the speed of current reduced in the same proportion( it will say the flow stays the
If different species are considered, the quantity to be used can be three times higher from one species to
same).
another. These results were obtained with species of the Simulium damnosum complex in West Africa.
METHODE
INTRODUCTION
Dans des
1977, Elsen
et
Elsen
Hebrard 1979, Elsen 1980a),
nous
avions montre que
la
larves de S. damnosum
larvaire,
de
concentration
la
des
Nous
le
calculer
realisation
d' un transit
ingere
par
enfin
du transit digestif des
s. l. vane en
fonction du
de
l' eau
egalement
avions
temps
necessaire
de temps ( Elsen
unite
etabli la
proportion
digestif des larves ( Eisen
donnees
vont nous
avions
sensibles entre
al.
1978),
d' autre
diverses
mais
pour
la
pour
volume
1980b).
Nous
des
1979).
et
dans
part observe
especes
du
d' elles
en
stades
larvaires,
temperature,
Dans une deuxieme etape, nous regrouperons
ces formulations en une equation permettant de
calculer le volume ingere par unite de temps.
La troisieme etape consistera d developper un
modele a partir de cette nouvelle equation et de divers
parametres complementaires( efficience de captage des
ces
section de la riviere).
ce travail.
des differences
une
(
particules en fonction de leur taille, la dose letal pour
l' insecticide concerne, le nombre de particules par
unite de poids du produit actif de cet insecticide, et la
Eisen
leur totale independance l' une
chacune
consideration
concentration des particules, vitesse du courant).
en
Toutes
complexe(
Dans une premiere etape, nous formulerons
successivement les relations qui unissent la vitesse du
transit digestif aux divers parametres pris en
dans le
particules
rapport a l' autre oblige de regrouper
obtenues
montre
foumir la base de la tentative de
modelisation que nous presentons
Nous
la
le
complet et calculer
fonction de leur taille a la fois dans l' eau
tube
stade
de
et
particules en suspension passant par
comment
avions
vitesse
temperature
de temps.
unite
Elouard
travaux anterieurs (
et
et
par
Nous discuterons ensuite brievement le modele
ainsi obtenu a la lumiere des donnees experimentales
qui ont permis d'elaborer les equations de base.
les valeurs
matrice
a
RESULTATS
laquelle on fera appel dans le cas dune programmation
du
modele.
Les parametres agissant sur l' ingestion.
1Presented at the 1st European Branch Meeting, SOVE, Montpellier, FRANCE, 11- 12 September, 1986.
2lnstitut de Medecine Tropicale Prince Leopold, Laboratoire d'Entomologie, 155 Nationalestraat, B- 2000
Antwerpen, BELGIQUE.
BULL. SOC. VECTOR ECOL.
DECEMBER, 1987
a.-
Le
larvaire.
stade
Rappelons
longueur
reelle
les
larvaires,
fonction de leur age, les jeunes larves
une
du
relative
vitesse
transit ( longueur
L' expression
en
pyramide.
Une analyse de
fourni un plan de regression significativement correle
relative
des larves
mathematique
la forme dune
sous
regression multiple appliquee aux donnees nous a
manifestent
parcourue) nettement plus rapide que celle
ages ( Eisen 1980a).
de particules, l' histogramme de la vitesse du transit
digestif se distribue dans un espace tridimensionnel
mais qu' etant
de la taille des larves
proportionalite
Nous avons montre ( Eisen et Hebrard 1979)
que, en fonction de la temperature de l' eau et du flux
transit
des differences
presente
stades
du
absolue
vitesse
parcourue)
peu marquees entre
donne la
la
que
555
L'expression generale de ce
aux valeurs observees.
de
plan de regression est de la forme:
la courbe ainsi obtenue est la suivant
Lr =
13
Lri= a • Li-
ou:
dans laquelle:
Lri =
b • T°=
a+
c •
C
3)
1)
T°= la temperature de l'eau en° C
longueur relative du tube digestif
le bol
par
parcourue
C=
alimentaire
le flux de particules par mm2
sec
pendant la duree de l' experience
les larves du
chez
Li=
longueur
du
reelle
i.
stade
On peut objecter dans cette equation que pour un
flux nul it existera malgre tout un transit digestif, ce
qui est illogique.
De meme, a des temperatures
larvaire i.
stade
negatives croissantes, on finit par obtenir une valeur
a
B=
et
deux
fonction des
parametres
milieu ( voir§
La
de
augmentation
inversement
c' est
varie
de
courbe
cette
la
facteur
du
l' on
que
stade
a•
Li-
B=(
Le facteur
a•
par
il y a
age):
plus
a•
B
Li -
biotope. Le plan de regression defini ci- dessus nest
applicable qu' a l' interieur de ces limites et, ainsi
l' artifice
L7
L7-
B
L'aspect de pyramide evoque plus haut indique
que les relations entre les parametres pris deux a deux
ne sont pas lineaires, mais ordonnees suivant deux
pentes oposees, le point de rupture entre les deux
pentes formant la zone du seuil.
C' est ce que les
B
done:
lines" (= lignes brisees).
Afin d' effectuer une analyse de regression, il est dans
anglophones nomment" split
B
L7
ce cas necessaire de transformer les variables. Perry
Li
L7
Ce plan de regression a ete defini
pour le dernier stade larvaire.
sept stades
2)
a•
considers, nous verrons que le modele s' accorde avec
nos observations.
a • L•- B
B) (
L7
multiplicatif vaut
B
Li-
a
digestif
larvaire,
fonction d' un
en
obtient
le
septieme est
des conditions incompatibles avec la vie des larves et
qu' il faut rester dans les conditions limites de leur
du transit
vitesse
mathematique suivant( rappelons qu'
larvaires dont le
une
transit
larvaire a l' autre
multiplicatif
Mais it va de soi qu' un flux nul ( courant nul ou eau
distillee !) et des temperatures negatives ( glace) sont
indique
a Page du
a dire a la taille des larves. La
stade
du
suivant).
relation
vitesse
proportionelle
done d' un
negative du transit, ce qui est tout aussi illogique.
constantes qui varient en
(
1982) propose d'utiliser les " variables factices" (=
dummy
variables"
des
anglosaxons).
Ces variables
s' obtiennent en considerant comme nulle la valeur
b.- La temperature de l' eau
La
concentration
dans l' eau
est
tenir compte
dans leurs
nombre (
la
insuffisante
de
La
courante.
et
des
des
premandibules
N) des
en
particules.
en
vivent
qui
particules
observee situee au point de rupture des deux pentes, et
suspension
elle- meme car
les larves
ce que
quantite
le flux de
particules
il faut
dans l' eau
passeront
depend des lors a la fois du
d' eau, c' est a dire
particules par
de la
Cette
vitesse ( v)
quantite est
du
le
flux ( C) des particules par mm2 de section de riviere
surface
approximative
diminuant de la valeur observee au point de rupture.
Nous avions, par exemple, observe un point de
rupture a 25° C qui prend des lors la valeur zero et les
autres temperatures sont reevaluees par soustraction de
mm3
concentration en particules, et
courant exprimee en mm/ sec.
en reevaluant les autres valeurs observees en les
des
25, ce qui donne pour chaque pente ( en regard des
temperatures experimentees) les deux nouvelles series
de valeurs suivantes:
premandibules)
T°
equivalant a:
10° C
T1°: - 15
C= N
v
T2°:
0
-
15° C
10
0
20° C
-
25° C
30° C
35° C
5
0
0
0
0
0
5
10
556
T1°
T2°
et
On
C)
particules (
En
C2.
plan
de
Lr=
les
sont
temperatures.
en obtenant
appliquant
b•
de
les
pour
les flux de
meme pour
deux
nouvelles series
C1
et
1' squation ( 3) du
methode,
cette
Ti° - c • T2°+
et oil L represente la longueur moyenne reelle du stade
larvaire considers et qui varie suivant l'espece
incriminee. A partir de cette relation et de parametres
complementaires, nous allons progressivement stablir
un mod8le qui devrait permettre de doser les
insecticides de la facon la moms empirique possible.
transforme en:
regression se
a+
factices
variables
procedera
d•
C1 -
1)
et (
C2
e•
4)
(
Les
L' examen des
relations (
DECEMBER, 1987
4)
nous montre
parametres
complementaires
le
et
modele.
que pour une duree d'expsrimentation dsterminee, la
longueur relative
etre
obtenue
du
reelle
parcourue par
u
soft
stade
larvaire
de temperature
particules,
soit
Si le
sinon
en
cependant
et
les
generaliser
facteur
4)
en
larvaires,
2).
Il
dune audace que nous sviterons
lutte
Rappelons
rsaliser.
en
on
7
stade
qui
est
le
le
utilisation pratique,
considerant
relation (
4)
a
que
dsfaut
ingere
volume
seul
stade
etre
7,
la
c' est
le
son
simplifie en
la
et
comme
le
modele ne
pour ce stade,
par
ete
dans la
Des lors, dans
modele pourra
ce
ete etablie
sera pas mis en
cependant que
plus resistant.
y
s' agit
1' absence
les larves de Simulies,
chimique contre
Eisen
1979)
les
rencontrees
dans l' eau ( TABLEAU 1).
Ces rapports
nous font apparaitre deux phenomenes: dune part la
confirmation dune capacite de capture des grosses
particules qui augmente avec rage des larves, mais qui
est neanmoins faible pour tous les stades, et d' autre
part une capacite de captage nettement plus elevse
pour
les
particules
comprises
entre
4. 7
et
9.4 µ
m
malgre leur nombre 6.5 fois moindre clans l'eau par
rapport aux petites particules qui sont ingerees en
proportion egale u celle trouvse dans l' eau.
Les
generalisation proposee.
de temps.
par unite
public (
l' eau des rivieres et dans le contenu intestinal des
differents stades larvaires de S. damnosum s. l. Nous
le redonnons ici complete par l'efficience de captage
des diverses categories de particules et qui s' obtient en
effectuant, pour chaque stade larvaire, le rapport entre
les proportions de particules rencontrses dans leur
tube digestif et les proportions correspondantes
donne
cette relation en
multiplicatif (
déjà
de flux de
ne vane pas,
stades
avions
proportions des tailles des particules rencontrses dans
larvaire
relation(
Nous
conditions
verification experimentale qu' il ne nous a pas
donnee de
Le
de la
amplitude, suivant
le
des
a.- L'ingestion des particules suivant leur taille.
moyenne
parametres.
plan courbe
appliquant
ne
de l' eau
stade
un
imaginer de
pourrait
de
pour
deux
alimentaire peut
considers pour
constantes
mesurant ces
le bol
de la longueur
partir
raisons qui font que la dsficience de captage des
grosses particules soit compensse par une efficience
Le developpement
la relation
ingere
de
qui permet
Elsen 1980b).
rappelerons
Nous
seulement
pour
necessaire
calculer
le
n'
y
rsaliser
est
un
base
transit
antsrieur
vraisemblablement son origine dans la morphologie
done
reviendrons
qu' il
matiere
plus grande au niveau de cette classe particuli8re de
taille des particules plutot quune autre trouvent
de
volume
fait 1' objet d' un travail
par seconde a
u
mathematique aboutissant
sur
et
des prsmandibules filtrantes et la dynamique des
le temps
fluides i3 leur niveau. Il y aurait done inter& u ce que
pas
T&,
complet (
exprims en secondes, qui vaut:
100 T
Tc—
5, 04457-
0,46295
Lr+
0, 03809
5)
Lr2-
0, 00024
Lr3
les
insecticides particulaires soient formulss en
fonction de cette categorie. Mais it faut tenir compte
de l'interfsrence avec la capture des autres categories de
taille.
Le probl8me peut etre resolu a partir du
TABLEAU 1.
On peut en effet en deduire le volume moyen
et ou:
T= temps,
en secondes, utilise pour
relation(
stablir la
occups par chaque categorie
4).
de
taille pour
100
particules capturees ( puisque 1' on traville avec des
Pour simplifier le calcul de leur
volume, nous postulerons que les particules sont
spheriques, mais en sachant bien qu' elles ne le sont
pas clans la realits, ce qui leur permet de s'emboiter
pourcentages).
longueur
Lr=
relative parcourue par
mentaire et qui s' obtient par
Le
volume
ingere
la
le bol
ali-
relation(
4).
clans le tube digestif et d' en occuper quasi 100 pour-
par seconde s' obtient comme suit:
cent
V—
0,002124
Tc
L3
3
6)
du
volume.
Pour
chaque
categoric
prendrons en consideration le diametre moyen.
nous
Les
volumes ainsi obtenus peuvent etre ensuite assignes
dune
valeur relative par rapport au volume total
des
DECEMBER, 1987
100
TABLEAU 2).
particules (
Ces
valeurs sont
tits approximatives, mais ce qui compte
sur
raisonnement
A
mod8le.
la
par
qui
6),
relation (
ces valeurs et
on pourra
de
volumes
en µ
6)
indiques
deduire le
it faut
m3,
multiplier
109.
par
TABLEAU 2
au
ou Ai represente le pourcentages de V occupe par les
le
particules de taille i, ce qui explique la valeur 100 au
le
volume
denominateur. En divisant ce volume par celui ( Wi)
celles obtenues
V
de une particule de taille i, nous aurons le nombre de
volume reel
ingere pour une categoric de taille donnee.
les
bien
est
a la forme theorique du
mene
de
partir
ici
particules i reellement ingerees par seconde:
Comme
109•
sont exprimes
de la
particules
de taille i
vaut
donc (
V•
7)
Ceci est capital pour un dosage d'insecticide
Ai
comme
par
exemple
le
Bacillus
thuringiensis H- 14, une fois que 1' on connait la dose
letale du produit utilise, c'est a dire le nombre
100
TABLEAU 1.
Ai
100 Wi
en
particulaire,
109 •
V•
relation
La fraction du volume ingere ( V)
les
occ3pee par
557
Les proportions des tallies des particules dans 1' eau de riviere et dans le contenu intestinal des
differents stades larvaires de Simulium damnosum s. l. et leur efficience de captage ( EC) par ces
larves( Danangoro. mars 1977. Cote d' Ivoire).
Tailles des
Eau de
particules
riviere
enµ m.
%
Stades larvaires
VII
VI
EC
%
%
V
IV
III
II
EC
%
EC
%
EC
%
EC
%
EC
1. 0
x
4. 7 73. 68
74. 18
1. 01
74. 16
1. 01
75. 26
1. 02
76. 53
1. 04
79. 87
1. 08
82. 11
1. 11
4. 7
x
9. 4 1122
14. 84
1. 32
14. 59
1. 30
13. 74
1. 22
15. 31
1. 36
15. 78
1. 41
15. 67
1. 40
9.4
x
23. 6
728
7.42
1. 02
8. 07
1. 11
7. 69
1. 06
6.90
0.95
4. 08
0. 56
2. 10
0. 29
23. 6
x
47. 2
4.92
2. 08
0. 42
1. 82
0. 37
2. 04
0. 41
0. 79
0. 16
0.27
0. 05
0. 12
0.02
2.90
1. 48
0. 51
1. 36
0.47
1. 27
0.44
0.47
0. 16
47. 2
-
-
TABLEAU 2. Volume ( V) par stade larvaire de chaque categoric de particule ingeree en fonction de leur
proportion( extrapolation du TABLEAU 1) et leur pourcentage correspondant du volume total des
particules ingerees.
Volume moyen
enµ m3)
de
particule
dans
Stades larvaires
une
chaque categorie
VII
V
VI
%
V
V
%
V
IV
%
V
III
%
6. 8
504
0. 24
504
0.26
512
0. 27
520
183. 5
2722
1. 32
2677
1. 41
2521
1. 35
2809
2352.0
17452
8.46
18981
9. 96
18087
9. 71
16229
19.92
23227. 8
48314
23. 43
42275
22. 19
47385
25. 44
18350
2252
95693. 2
137186
66.54
126073
66. 17
117720
63. 21
43566
53. 47
0.64
V
II
%
543
2. 81
3.45 2895'
V
558
%
5. 00
15. 00
2875 25. 76
9596
49. 71
4939 44.26
6272
32.48
2787 24.98
-
-
DECEMBER. 1987
558
de
minimal
larve doit ingerer
qu' une
particules
pour
simplification, est la suivante:
mourir. Nous y reviendrons un peu plus loin.
On
d' autre
peut
de taille i
particules
le
obtenir
part
47080, 98 • T • M •
de
nombre
dans
seconde
par
passant
une
Q—
section de 1 mm2 de la riviere par la relation:
N
Bi
8)
v
Bi • Wi • N • S •
v
10)
(
Ai • Z• L3•( 5,04457- 0,46295 Li.+0,03809 L,2-0,000241. 3)
Dans ce modele, it n' y a que quatre parametres d
mesurer:
100
le nombre de particules( N) par mm3 d'eau.
N=
ou :
de
nombre total
de
Bi=
dans 1
particules
d' eau
mm3
la temperature( T ) de l'eau en
riviere.
C.
la section( S) de la riviere en m2.
de N
pourcentages
occupe par
les
la vitesse( v) du courant en m/ sec.
particules
i.
A partir desquels se deduit le flux de particules ( C=
du
vitesse
v=
N•
courant en mm/ sec.
v).
Tout le reste constitue une constante qui
depend u la fois de l' espece consideree( L) et du produit
En divisant la
relation (
8)
la
par
relation (
7)
nous
utilise ( M ).
obtenons le nombre de particules i devant passer par
seconde dans une section de
i
particule
ingeree
soit
N•
Bi • Wi •
109
b. Autres
V
1 mm2 pour qu' une
DISCUSSION
seconde:
apres une
Dans cette nouvelle formule, nous voyons qua
9)
v
debit egal et pour une meme turbidite, la quantite
Ai
obtenue va changer en fonction de la vitesse du
courant qui intervient egalement au denominateur dans
parametres.
le calcul de la longueur relative parcourue par le bol
Si
i
represente
de l' insecticide
particules
de cet insecticide
9)
la
quantite(
q) de
section
une
categorie
pour obtenir
jeu croise de la vitesse du courant et de la section
devant
mm2
des
taille
epandage
it faut que la
la dose letale( M)
particules
de 1
relation
alimentaire. Or, pour un meme debit de la riviere, la
quantite d'insecticide qui va passer par unite de section
de la riviere variera considerablement en fonction du
de
choisi, pour qu' un
soit efficace,
soit multipliee par
dans
la
passer par seconde
M
pour que
ingeree
soit
pendant cette seconde:
M• N•
q
En
109
tenant
quantite
particules
sec.
d'insecticide/
de la
riviere.
Par exemple, si l'on considere
meme,
mais
la
quantite
d' eau,
par
consequent
d' insecticide, passant par unite de section vane dans ce
mm2
cas- ci du simple au double!
vitesse
dune
Le modele n'est encore que theorique en ce sens
du
courant
de
part
la
en
m/ sec
et en
Z)
quantite (
de
dans 1 mg de produit actif et d' autre part de
( S) en
de la riviere, nous obtenons la
que les coefficients reels restent encore u calculer.
Mais en y appliquant les valeurs experimentales que
nous
avons
obtenues
et
en
nous
referant
u
la
m2
de
produit actif(
la dose letale
pour que
de
la
compte
section
v
V ••A
exprimant
particules
la
Bi • Wi •
totale
dune part une section de 1 m2 et une vitesse de
courant de 1 m/sec, et d'autre part une section de 2 m2
et une vitesse de courant de 0.5 m/ sec, le debit sera le
Q u
deverser dans la
ingeree
soit
riviere
apres une seconde
passage:
constatation faite ci- dessus, nous obtenons, suivant
1' espece, une valeur de 1. 4 u 1. 8 fois plus elevee pour
une section de 2 m2 et une vitesse de 0. 5 m/sec que
pour une section de 1 m2 et une vitesse de 1 m/ sec.
M •
Bi • Wi • N •
Q
Ceci indique que le dosage doit se faire au niveau de la
S•
v
section la plus large de la riviere.
mg.•
g.
Z• V
Daautre part, u meme debit, plus la vitesse du
courant est elevee, plus les valeurs obtenues s' ecartent
ou
V
suivant
la
depend de l' espece
consideree
la
y
relation
simplifier
Lr.
relation (
(
5)
6)
et
l' ecriture,
apres
Lr
par
nous
et
est calcule
la
montre que si, a mime debit, on calcule la valeur de
Pour
Q dune part pour l'espece u ingestion la plus rapide
l' abreviation
dans le courant le plus rapide, et d'autre par pour
relation (
conserverons
Des lors, l' expression finale du
en fonction de l' espece. Le jeu croise de ces resultats
par
avoir remplace
Te
4).
modele,
apres
l' espece la
plus
lente dans le
courant
le
plus
lent,
DECEMBER, 1987
nous
des
obtenons
qui
valeurs
du
vont
simple
au
triple!
Ceci
peut parraitre effrayant, mais
dans le
calcul
ment
dans
utilise
les
la
multiplie allegrement
minutes,
ou
600
valeur
ce qui
Faut- il
le dosage
par unite de temps. Ann. Soc. beige Med. trop.
60( 2): 213- 222.
600! ( 10
ci- dessus.
la dose
dans les Vosges
rappeler que
Ce
en
a
Belgique( donnees
d' autres
s' agit
especes
imperieux de
tenir compte
d' un dosage
calcul
fondamentales
et
de
plutot
de
empiriques successifs avant
Precisons
etudier
et
dii etre
beige Med. trop. 59( 1): 49- 58.
de
et que ceux abordes
du
l' esperons, la
ici
al. (
Afrique de 1' Ouest.
recherches
209- 217.
par
Ann. Soc.
I. Influence du sexe et de
Ann. Soc. beige Med. trop. 58( 3):
tests
Guillet, P., J. M. Hougard, J. Doannio, H. Escaffre,
a
apparaitre,
dont
approche
recents resultats appliques obtenus par
particules.
Simulium damnosum ( Diptera, Simuliidae) en
l' espece.
faisant
ces
qui
donc
un resultat.
dune telle
de
Elsen, P., D. Quillevere, and G. Hebrard. 1978. Le
transit intestinal chez les larves du complexe
ne constituent qu' une
probl8me en
necessite
nature
dans le
tlitonner
d' aboutir a
de la
Or it
enfin qu' il reste plusieurs parametres
premiere approche
les
les
poursuivre
que
Simulium
complexe
France,
est
ces parametres
du
1' Ouest. II. Influence de la temperature de l'eau,
de la concentration des particules en suspension
conditions
d' exposer. Il
larves
de
non publiees).
d' autres
et
conferment ce que nous venons
les
chez
damnosum ( Diptera, Simuliidae) en Afrique de
triple pour obtenir un effet positif ( Noirtin et al.
1981) et que Von rencontre actuellement les memes
problemes en
Elsen, P. and G. Hebrard. 1979. Le transit intestinal
letale,
calcul
Afrique Occidentale
applique en
Consequences des variations observees sur le
temps dun transit complet et le volume ingere
operationnels
d'epandage.
applique au point
Simulium damnosum ( Diptera,
Afrique
de 1' Ouest.
IV.
en
systematique-
inevitablement les imprecisions du
masque
pas
est considerable-
de
empirique
faut
ne
calculee par
triple mentionne
calcul
au
epandages
secondes),
ment superieur au
fait, joint
facteur
ce
it
ici, le facteur de
exposé
Or
pollee n' intervient pas.
nous
complexe
Simuliidae)
oublier que
base
du
559
Guillet
et
and
J.
Duval.
1985a.
Evaluation
de
la
sensibilite des larves du complexe Simulium
damnosum a la toxine de Bacillus thuringiensis
H- 14.
I.
Methodologie. Cah. ORSTOM, ser.
Ent. med. Parasitol. 23( 4): 241- 250.
1985a, b, c, d) en Cote d' Ivoire sont une belle
Guillett, P., J. M. Hougard, J. Doannio, H. Escaffre,
illustration.
and
REFERENCES CITED
J.
Duval.
Evaluation de la
complexe Simulium
1985b.
sensibilite des larves du
damnosum a la toxine de Bacillus thuringiensis
Elouard, J. M.
1'
des
absorption
vitesse
P. Elsen.
and
du
Variations de
particules alimentaires et
du transit digestif
parametres
1977.
en
milieu
fonction de
les
chez
de la
certains
larves
de
H- 14.
2.
Sensibilite relative de quelques
groupes d'especes et possibilites d' utilisation de
doses diagnostiques.
Cah. ORSTOM, ser. Ent.
med. Parasitol. 23( 4): 251- 255.
Simulium damnosum Theobald, 1903 ( Diptera,
Cah. ORSTOM,
Simuliidae).
Parasitol. 15( 1):
ser.
Ent.
med.
Guillet, P., H. Escaffre, J.
Bakayoko.
29- 39.
M. Prud'hom, and S.
1985c.
Etude
des
facteurs
conditionnant l' efficacite des preparations a base
Eisen, P.
La
1979.
ingerees
dans les
damnosum
Rev. Zool.
nature et
la taille des
les larves du
par
afr.
rivieres
complexe
particules
Simulium
de la Cote d' Ivoire.
93( 2): 476- 484.
de Bacillus thuringiensis
larves
du
Diptera, Simuliidae).
et
H- 14 vis- à- vis des
Simulium
complexe
1.
damnosum
Influence de la nature
de la taille des particules.
Cah. ORSTOM,
ser. Ent. med. Parasitol. 23( 4): 257- 264.
Elsen, P.
du
1980a. Le transit intestinal chez les larves
complexe
Simuliidae)
Influence du
la
saison.
Simulium
en
stade
Afrique
damnosum
larvaire, du
( Diptera,
1' Ouest.
de
nycthemere et
III.
de
Ann. Soc. beige Med. trop. 60( 2):
203- 212.
Guillet, P.,
H. Escaffre, J.
Bakayoko.
M. Prud' hom, and S.
Etude
1985d.
des
facteurs
conditionnant 1' efficacite des preparations a base
de Bacillus thuringiensis
larves
du
complexe
H- 14 vis- à-vis des
Simulium
damnosum
Diptera, Simuliidae). 2. Influence du temps de
Elsen, P.
1980b.
Le transit intestinal
chez
les larves
contact et
de la
quantite
de
particules naturelles
DECEMBER. 1987
560
en suspension clans
Ent.
med.
l'eau.
Cah. ORSTOM,
sdr.
Parasitol. 23( 4): 265- 271.
Vosges:
les origins de leur pullulation et les
mdthodes
de lutte.
Cah. ORSTOM, sdr. Ent.
med. Parasitol. 19( 2): 101- 112.
Noirtin, C., B. Boiteux, P. Guillet, C. Dejoux, F.
1981.
Beaucournu- Saguez, and J. Mouchet.
Les
simulies, nuisance pour
le bdtail dans les
Perry,
J. N.
1982.
Fitting split-lines to ecological
data. Ecol. Entomol. 7: 421- 435.
DECEMBER, 1987
IMPORTANCE OF VECTOR OVERWINTERING TO DISEASE MAINTENANCE'
W. C. Reeves2
When I
thought
is
to discuss the
asked
was
overwintering to disease
vector
If
that the answer was simple.
was
in
endemic
importance
is dependent
an area and
of
than a transovarian mechanism would be ruled out."
my first
This statement anticipated the basic question that still
a pathogen
concerns us today— how do arboviruses overwinter or
maintenance,
on a vector
for its
maintenance, the vector must survive adverse periods or
the
pathogen
pathogens
can
infections in
disappear.
It
It is quite clear that the endemic persistence of an
for
survive
long
host
logical then to
periods
on
periods
and
in the
Mosquitoes
droughts
and
consider
to
unfavorable
rapid reproduction.
simple.
as
chronic
absence of a
as
long living
mosquitoes
continuous
answer was
low
survive
how
their
Again, the
or
and
seasons
are
favorable.
If this is
disappear
will
until
has
must again
plagued researchers
virus
In sub-
transmission.
sufficiently to
effective vector control programs also can interrupt
conditions
along
with
transmission.
However, in spite of such disruptions,
some arboviruses seem to persist as endemic infections
in many regions of the world.
The principle hypotheses that have been advanced
any
to explain the survival of mosquito-borne arboviruses
on the vector.
At this point I decided I
question that
continuous
and tropical regions, prolonged dry or rainy
also may disrupt transmission.
In both
temperate and tropical regions, prolonged drought or
when
reintroduced
in the winter,
or
larvae,
eggs,
not accomplished, the species
it is
is dependent
virus that
develop
will
generations
precludes
high temperatures
assure that a nucleus population will survive and that
subsequent
temperate areas
shortened daylight hours and low temperatures
inactivate the vector population to a degree that
tropical
extended
In
transmission.
relatively
adults,
Their life table has to be
pupae.
to their continuous
arbovirus in any area is threatened annually by
circumstances that may interrupt continuous
a vertebrate
seemed
adverse
further
However,
vector.
survive
any period
transmission?
realized that a number of vector-borne
will
I
consideration
survive
face head on
for many
the
years.
in temperate areas through adverse periods and their
reappearance under favorable circumstances are:
How do arthropod-bome pathogens survive periods
adverse
to their
transmission? In the
continuous
interest
1.
going to limit my further considerations to
the mosquito-borne arboviruses although my thoughts
of time
I
addressed the problem of virus survival was made
Hammon, Reeves,
1945.
with
the
and
Galindo
overwinter relationships
encephalomyelitis and
hibernating
Culex
Si Louis
tarsalis.
This
not
know
the
surviving
having had
dependent
winter
a
whether
the
hibernation
of western
blood
meal
on such a meal.
carry
over
in
chances
or
and reinitiate serial transmission under favorable
of
are
this
newly
in the
survival
If the former is the
the mosquito vector
by
we
species
decreased
whether
circumstances.
equine
encephalitis viruses to
species was the
period
retain their ability to transmit infection by bite
in
were concerned
discovered primary vector of these diseases
western United States. They stated," Unfortunately,
do
summer. Females feed on an infected vertebrate
host in the fall, survive the adverse period, and
apply to many other vector-borne pathogens.
To my knowledge, the first statement that
will
The virus survives in diapausing adult female
mosquitoes that are the primary vectors in the
am
any
by
is
2.
The virus persists in the vector population by
transovarial transmission. Any life stage of the
vector
that
survives
an
unfavorable
period
may carry the agent until conditions favor
serial
transmission
vertebrate
hosts.
between
vectors
and
This concept infers that the
virus is a commensal parasite in
the vector
case,
that has become partially adapted to vertebrate
other
hosts.
Presented at the 18th Annual Conference of the Society of Vector Ecologists, University of California, Riverside,
November 20, 1986.
2Department of Biomedical and Environmental Health Sciences, School of Public Health, University of California,
Berkeley, California 94720 U.S A.
562
The
3.
of
hosts
vertebrate
and
in the blood where it can
reappears
infection
renewed
infection in the
persists as a chronic
virus
organs
periodically
be a source for
of a vector population.
DECEMBER,
efficient type of cycle are La Crosse, California, and
Rift Valley fever viruses that are transmitted by Aedes
mosquitoes.
periods
or
Eggs of these vectors survive cold winter
prolonged
potentially
4.
The
does
virus
in
not remain
be
what appears to
but actually is reintroduced
longer
intervals by migratory or
annually
vagrant vertebrate hosts or vectors that come
areas
endemic
or at
from
areas
is
more
but to
me the
transmission
where
continuous.
1987
infected
environmental
dry periods.
mosquitoes
conditions release
J arge broods of
emerge
once
the eggs from
diapause in the spring or summer. Prototype California
encephalitis virus survived for eight months in infected
Aedes eggs even when they were repeatedly frozen and
thawed before hatching.
A most interesting alternative pattern for a
California group virus is just now emerging. The Jeny
Other hypotheses have been
four
most plausible are the
host
period
when
in
Next, I
want
these
each of
a mosquito vector or
has been infected
species that
favored
conditions
In
above.
alternatives, the virus persists
vertebrate
advanced
rapid
during
serial
a
passage.
in favor
of
some evidence that virus can persist
in
briefly
to consider
the evidence
hypothesis.
each
There is
female
have
mosquitoes that
Virus has been isolated from
meal.
collected
mosquitoes
in
blood
taken a prewinter
female
adult
In
mid-winter.
addition,
Slough variety of Jamestown Canyon virus has Culiseta
inornata
as
its
vector
is
California
this
population
peaks
a
in California
winter-time
in the
winter
In most of
mosquito.
and
spring.
The
The
population survives the summer as females in a poorly
defined aestivation. We are fmding that Jeny Slough
virus is very efficiently transmitted transovarially and
the virus probably survives the adverse summer period
in a few quiescent females. It is hypothesized that these
females can transmit virus by bite late in the fall and that
their progeny are infected transovarially.
individual experimentally infected female mosquitoes
have retained infection when held at outdoor
chronically infected vertebrate hosts that can be sources
temperatures for over eight months,
of vector infection. Western equine encephalomyelitis
However, few
period.
from
overwintering
of such
studies
diapausing
and
do
virus
female
not
To
many
mosquitoes
had
turn
to
the
viruses
in
second
their vectors
made
and
a prewinter
most
alternative,
hosts in midwinter. However, we have not been able to
meal
infect vectors on chronically infected birds, so the
question still is, can a vector become infected by feeding
evidence
is
of
more common than was
believed previously. There is evidence that at least 50
arbovinuses can have some degree of transovarial
Important
transmission.
pathogens,
such
as
yellow
fever, dengue, Japanese B, St. Louis,
Murray Valley,
California, Ross River, Rift Valley, sandfly fever, and
stomatitis
vesicular
viruses
are
in
this
virus can persist in organs of birds for up to 10 months
and we have recovered virus from naturally infected
most
infection
transovarial
is
blood
dissociation.
not undergo gonotrophic
rapidly accumulating that
a winter
have indicated that
populations
females have
including
isolations have been
The third alternative is that virus overwinters in
on such hosts?
I will not discuss the probability that viruses are
reintroduced annually to areas where infection
disappears in the winter. Data are very fragmentary in
spite of extensive efforts to trace movements of species
that are known hosts and that migrate great distance
each year.
SUMMARY
group.
Interestingly, the rate of transovarial transmission of
most agents
does
not seem to
that this mechanism alone
multiple
generations
vertebrate
host.
without
However,
overwinter survival.
be
sufficient to consider
will allow virus survival
In the
amplification
it
would
in
suffice
most efficient cases,
for
a
fast blood
transmit
meal after emergence and male
infection
sexually to
Extrinsic incubation is completed
pupal
they
stages.
progeny
during
Some outstanding
can
females.
of
of
of virus in the vector represents the basic maintenance
cycle. If a virus is endemic in a temperate area and is
the larval and
examples
three classes
90
take their
uninfected
at least
arboviruses. In the first class, transovarial transmission
progeny from infected females are
infected. In addition, a portion of female progeny from
can transmit virus when
assume that there are
for
percent or more of
infected females
In summarizing the relationships of vector
overwintering to arbovirus maintenance, I am going to
this
transmitted by Aedes mosquitoes, it must fall into this
class as overwintering of most Aedes is in the egg
stage.
The second class is arbovinuses transmitted by
Culex mosquitoes. In this instance the primary mode
of overwintering is in
diapausing adult females. Virus
DECEMBER, 1987
may
BULL SOC. VECTOR ECOL.
overwinter
transovarially
or
persist
in infected
females that feed
on a virus source prewinter.
mosquitoes
fall into this
reversal
also
of the
regions with
season
high
The third
of
pattern
Culiseta
except
adult mosquito
for the
activity in
of virus to an area.
In this instance,
vectors still must survive the winter and be available to
reintroduction
be infected in the spring or early summer or virus
transmission will not occur.
The following speakers will expand on the
summer temperatures.
class represents arboviruses that
563
do
not
utilise overwintering vectors but depend on chronic
infection in vertebrate hosts for overwintering or for
mechanisms for overwintering of four major genera of
mosquitoes.
understanding
This information is critical to our
of pathogen
maintenance.
BULL SOC. VECIDR ECOL, 12(2): 564- 567
DECEMBER, 1987
THE FUTURE STATUS OF ARBOVIRUSES IN NORTH AMERICA'
W. C. Reeves2
When Gil Challet invited
he
colloquium,
in this
me to participate
to address three questions
me
asked
concerning the future importance of diseases
These questions were:
arboviruses.
caused
by
the encephalitis viruses developed very rapidly in the
1940' s. Primary vectors, such as Culex tarsalis and
Culex
pipiens
were identified and control programs
developed that targeted these species. It was found that
inapparent infections in wild birds were the primary
Will the diseases that
1.
concern
still
today
us
be
important in the future?
2. Will
be
new arboviruses
health
3. Will
to pose public
shown
problems?
we address the control of arbovirus
do
as we
diseases
now or use new approaches?
of vector infection.
Infection and clinical
disease in humans and most domestic mammals was
accidental and of no importance as a source of vector
sources
infection.
In the 1940' s, California encephalitis and Colorado
tick fever viruses were discovered and associated with
human diseases. Since 1950, another 51 arboviruses
were discovered in North America but only two, La
Crosse and Jamestown Canyon viruses, are frequent
He did
not
encompassed and
to
be
Orange
restricted to
In
a
specify the geographical area to be
I assume he did not want my remarks
County, California
response to the above questions,
brief background
the
about
America today.
I
concern
diseases of
in North
world are known to be endemic in North America and
few have been associated with a significant number of
cases of disease in humans.
This brief review has
us
then attempt to make some
will
years and
must face.
discuss
mosquitoes as vectors.
Today, 58 of the 504 arboviruses that occur in the
reasonable predictions of what could evolve
15 to 20
Culiseta
will give you
arboviral
health importance that
public
I
disease in man. These two viruses utilize
small mammals as their principal hosts and Aedes or
causes of
in the
next
illustrated the rapid development of knowledge on
some specific problems we
arboviruses and their associated diseases in this century.
I will focus this discussion on viruses that
have been
human diseases.
associated with
Predictions regarding the activity of endemic
viruses
Historical
Background
Our knowledge
human disease has
only
six
world.
by
was
with
1930. In 1930,
western
viruses
animals (
were
discovered
were
Blue tongue,
EEE),
SLE)— were important
in North America
and
viruses ' will
continue
to
appear
Knowledge
and
populations. I do not believe that any of these infections
will
disappear in the foreseeable future.
Each virus
seems to be firmly imbedded over extensive areas in a
three of
silent cycle between vectors and wildlife hosts. In some
instances there is transovarial transmission of infection
WEE),
in the vector populations, which provides a most
encephalomyelitis (
eastern equine encephalomyelitis (
encephalitis (
these
periodically as epidemics in both rural and urban
five
other
domestic
equine
that
annually in their endemic areas as sporadic cases and
fever, Nairobi sheep disease, Louping ill,
stomatitis). From 1930 to 1940, only nine
arboviruses
encephalitis complex, and Colorado tick fever. I must
predict
the only one associated with
swine
additional
considerable about— WEE, FFF, SLE, the California
had been isolated in the
the
and
pathogens of
and vesicular
these—
associated
evolved since
arthropods
human infections
African
largely
Yellow fever
important
Let me turn now to the diseases that we know
arboviruses
that infect vertebrate hosts and are
viruses
transmitted
of
St. Louis
efficient reservoir of
infection.
Eradication of these
pathogens of man
cycles is impractical, economically unfeasible, and
history of
would require such drastic reductions of the vector and
of the natural
Presented at the 18th Annual Conference of the Society of Vector Ecologists, University of California, Riverside,
November 19, 1986.
Berkeley,
California
94720, U.S A.
DECEMBER, 1987
host
vertebrate
BULL. SOC VECTOR ECOL
is impractical
It
of projects to
immunize the
also
it
that
populations
undesirable.
could
be
even
this time to think
at
hosts
565
and expensive
task.
However, it is the only way to
rapidly control an epidemic that is in progress. These
to decrease
infections have a very short season when they are active
the competence of vector populations through genetic
and once clinical cases are identified, it can be assumed
alterations.
that many people already are infected. The exception to
The
wildlife
inevitably
question
While this may be technically
biology,
molecular
The majority
Why
arises
humans from
vaccines to protect
develop
not
diseases?
all of these
in today'
the above generalities about
the possible value of
vaccination and epidemic control are the exotic viruses,
s era of
such as yellow fever, the dengues, and Ross River virus
is that it is impractical.
in which humans develop a viremia sufficient to be a
possible
the response
or
infections in
inapparent
usually is
small. A very large number of persons would have to be
vaccinated at a high cost to prevent relatively few cases.
A major problem in arbovirus research over the
past 50 years has been to determine how these agents
Public health
survive the winter or are reintroduced each year into
of these
future
possible
area
officials and the medical profession will
high priority
not put a
man are
in any
and the number of clinical cases
in
on vaccination
anticipation of
epidemics although once an epidemic
is
occurring, it creates a widespread concern, even panic.
However, once an epidemic develops it is too late for a
vaccine
in
to be effective.
be
an endemic area still would
from the bites
of
infected
In
vaccinated persons.
will not
of these
an economical
infection
To
being
keep
I
tick
fever
must conclude
man. It also is of continuing interest that in the average
vector populations at
summer in the United States, 50 percent or more of the
febrile illnesses that involve the central nervous system
against
these infections
by
in
to vectors
caused by vector-borne viruses that already have been
with
is for individuals to
will
be
rare.
avoid exposure
circumstances where suppression of vector
is impractical.
populations
It
some of these cases will be shown in the future to be
infections
suppression of vector populations to
alternative
should
be
possible to continue to suppress vector
populations in urban and suburban areas to levels that
will
interrupt basic maintenance cycles between
This will require the
vectors and animal hosts.
establishment
surveillance
favor
in
virus
and
Detection
of
to
immediately
the
vector
minimize
the
with
remind you that there are 504 known arboviruses and
activity
to
population of
hosts,
or
and
infection
human
potentially
be
urban centers must
to
levels that
exposure.
of
epidemics
their control.
infected
Control
will
a
Suppression
adult vectors
is
a
peeeent are endemic to our region.
Tourists,
other travelers, and immigrants continue to have onsets
significant
of exotic arbovirus diseases after their return to or entry
responded
into North America. For the human pathogens, I would
list dengue, yellow fever, Venezuelan equine
encephalomyelitis, Japanese B encephalitis, and Ross
prevent or
depend
on
River viruses as some likely candiciatts. If such agents
fire- fighting
are introduced and the infection becomes established in
native vectors and hosts, control or eradication will be
cannot
and
only 10
cases.
an effective program to suppress
population
human
recognition
approach
in
Exotic vectors and viruses
to monitor climatic factors that
vector populations, virus
virus
vector populations
of man.
An additional prediction is that exotic viruses and
vectors will be introduced into North America. I must
and maintenance
vectors
be isolated. Current efforts to associate these
types of illnesses with known arboviruses have been
unsuccessful. I also anticipate that new techniques will
lead to the isolation and identification of additional
viruses from arthropods and vertebrate hosts and each
of these will have to be evaluated as potential pathogens
or will
intensive
of
maintenance
systems
activity,
laboratories. I suspect on epidemiological grounds that
and
learn to live
must
threshold levels where transmission to man
The only
in humans cannot be diagnosed by the best diagnostic
endemic viruses, such
will remain as endemic
for the foreseeable future. We
question. However, it remains to be answered for the
other major pathogens.
So far, these studies have not
opened new avenues for virus surveillance or control.
It is surprising that more of the 58 arboviruses we
WEE, FFF, SLE, La Crosse, Jamestown Canyon,
Colorado
complex in these vectors has partially answered this
know are present in North America have not been
associated with illness. The vectors and wildlife hosts
of many of these viruses have frequent contact with
the best protection
I believe that
be endemic areas. Demonstration of
transovarial transmission of the California virus
what appears to
by
transmitted to susceptible persons.
summarize,
vectors.
humans
surrounded
maintenance cycle
viewpoint,
to
provide
will
if
addition, vaccination of
an effective program
low levels
infection
at risk of
vectors even
have any effect on the basic
infections in wildlife.
From
that
as
Any unvaccinated person living
source of infection for domestic and semi-domestic
of
a
large
very difficult
very difficult
and expensive.
566
I
also expect that exotic vectors will
introduction
of
United States
Aedes
do
include aquatic
Such developments
continental
are desirable but almost inevitably will serve as sources
of vector breeding and provide habitats attractive to
vertebrates that are hosts of arboviruses. Related to this
problem are current programs that plan to use reclaimed
movement of products, such as used
tires,
is
hand before it is
out of
We
recognized.
have been infected
not appear to
If that had
immediate
the
represented
vectors
that
and
vector population.
infection that
of
reservoir
belts"
increased interstate
and
what can
it
occurred,
would
establishment
to
spread
would
and vertebrates and
with an
transovarially in
exotic pathogen that was maintained
have
green
environments within urban areas.
rapid spread
fortunate in this instance that the introduced
were
establish "
with
problem
vectors
the
recent
happen
illustrate
transportation
international
The
and
unrecognized
over an extensive area
modem
into the
albopictus
its
and
be introduced
be very difficult. The
and their eradication will
DECEMBER, 1987
become
of
a
native
waste water to create marshes and wildlife habitats
adjacent to or near urban areas.
A fourth problem is the constant expansion of the
urban- suburban area into agricultural or unimproved
lands, which increases the exposure of residents to
vectors. A significant part of the problem has been the
establishment of senior citizen communities in rural
This development is a recognition of the
areas.
increased aging and unique needs of that population.
established
However, from an epidemiological viewpoint, this can
Societal
to effective
changes related
control of
I
Gil Challet' s third
want to turn now to
Will
the
utilize
biological,
they
majority
I believe
of
our
A fifth problem is the increased difficulty of
do
developing effective systems to dispose of solid wastes
from our society. Used tires and a wide range of metal
and plastic containers provide a very attractive breeding
it. However,
be
to
develop
chemical,
successful, we are
society. Let
as
site for some mosquito species. Indiscriminate disposal
of such items on roadsides, in yards, or in densely
going to have to
vegetated areas makes them particularly difficult to find
illustrate this
me
examples of current problems that
unless
developed for
insofar
will allow
live in
we
society
new approaches to control or change the
attitude of our
worse
we will continue
present
and physical methods of control
are effective and the
either
question.
we address the control of arboviruses as we
now or use new approaches?"
to
radical
some
I believe
new
A sixth problem is the increasing number of
become
persons that are utilizing wild-land habitats for
will
approaches
are
that are acceptable to
vector management
vector
lawmakers.
developments have made
increasingly difficult in urban and
recent years, several
control
suburban
human
The
areas.
increasing
has been
size
and
by
and control
with some
the general public and
In
lead to an increased exposure of the age group that is the
most susceptible to SLE.
arboviruses.
density
of
recreational
purposes.
Such areas usually have no
organized resource for vector control and many vectorborne diseases
prevail
in
such
habitats.
It can be
expected that recreational exposures will result in an
increased number of infections with Colorado tick fever
and the encephalitis viruses.
aging,
A seventh, and perhaps the most important
poorly designed facility for disposal of waste water and
Epidemics of St. Louis
sewage from such areas.
problem, is the constantly increasing legal and social
populations
in
encephalitis
adaptation of
surface water
breeding
It
site.
and replaced
biological
in the
near
A
is
in
for
underground and
and will continue to
a
need
or
vectors
be difficult
to redesign such
new
chemical
or
have to be found that
control will
distance
problem
purpose.
Simultaneous to this change in the social
attitude, the genetic resistance of vector populations to
development of alternative and acceptable methods for
of
management of vector populations. I see a possibility
that pheromones and sugars may be used as effective
baits for the attraction and control of vectors,
particularly in urban environments. Very little research
has been done on the pheromones of major disease
vectors.
is
Current research is showing that adults of
the need to establish
vector species, such as Cx tarsalis require one or more
to dispose of sewage
sugar meals daily. Use of these agents as attractants to
a physical or chemical killing agent would
urban
centers
without
of vectors.
A third
control and on modification of environments for any
insecticides has developed more rapidly than the
will
such situations.
reasonable
restrictions on the application of chemicals for vector
of
second unsolved problem
production
the
urban areas as a major
economical and effective methods
within
reflected
be redesigned
future. Control of vectors in
There is
exclude
methods
are effective
in
an
unlikely that the thousands
seems
expensive.
facilities to
systems
drainage facilities
underground systems
and
both
vectors to
disposal
miles of present
have
populations
urban
Culex
paralleled
revolutionize control programs.
is that
our
society
wishes
to
major
future
research effort.
This is an area for a
DECEMBER, 1987
In
BUIL SOC VECTOR ECOL
summary, I
can
only
above problems will not
be
that vector populations
will
the above
environments
lead to increased
anticipate
in the future.
exposure
that
the
rapidly. I believe
increase in many of
resolved
of
This
humans to the
problems.
will
be
567
We cannot hope that old control methods
effective or acceptable
A new
could
develop
arbo-
challenging problem that will face them is to find ways
viruses.
new
approaches.
It may be that the most
to alter social attitudes regarding environmental
modifications
Conclusions.
I hope the
in the future.
generation of research and control workers will have to
and
legislation,
particularly
with
reference to actions based on feelings of vocal groups
above examples
have illustrated why
new approaches to control of vectors of arboviruses will
have to be developed rapidly to
manage a
variety
of
rather
than on scientific facts.
I cannot predict the
probability of or timing when these challenges will be
met.
DECEMBER, 1987
BULL SOC VECTOR ECOL, 12(2): 568-579
OVERWINTERING MECHANISMS OF NORTH AMERICAN CULISETA12
W. K Reisen3
ABSTRACT: The distribution and life history patterns of Culiseta species found in America, north of Mexico, were
Culiseta species were classified into four of the five possible categories using the Wesenberg-Lund
by Frohne. The overwintering strategies of the arbovirus vectors, Culiseta melanura and
Culiseta inornata, were described in detail. Culiseta melanura overwinters as larvae beneath root mats. All larval
Fourth instar larvae
stages are present during winter with development slowed by cold winter temperatures.
reviewed.
as modified
system
accumulate during winter and pupate during spring, perhaps in response to breeding site enrichment by vernal runoff
associated with snow melt Culiseta inornata abundance patters vary with temperature, being summer active in the
latitudes
colder northern
and winter active
in the
warmer
southern
latitudes
of
its distribution.
Females from
California remain reproductively active throughout the year and could not be induced experimentally to enter
reproductive diapause. Flight and host-seeking activity is arrested by extremes in temperature during mid-summer
and winter. Aestivation is preceded by the accumulation of hypertmphic fat without an associated reproductive
dormancy.
Types
Because
terms
be
used
useful
of confusion among the use of
to describe
mosquito
the onset to
at
will
which
terminology
to
aestivation)
related
the
overwintering, it may
briefly
be
define
either
in
dormancy
increases
degree
and the
from
quiescence
consists of eight subgenera,
circumglobally.
In
North
are
present
The
not
be
intensity
of
may
of preparation required
through
distributed
the
rare cases
to temperature( athermopause).
are
America, the genus is comprised of eight species, which
Dormancy
temperatures, or
which
some of the
in
used
The genus Culiseta
different
may be initiated in
low ( hibernation) or high
discussion ( TABLE 1).
response
Distribution.
Dormancy.
of
In
diapause.
grouped
into three
subgenera (
TABLE 2).
The
distribution of all eight species is essentially temperate,
although the ranges of Cs. melanura and Cs. inornata
extend to the most southerly portions of the United
States.
Conversely, the distributions of Culiseta
alaskaensis and Culiseta impatiens extend well north of
the Arctic Circle.
immature mosquitoes, the intensity of the response is
difficult to define
and often
termination are used to
adult
female
mosquitoes( males
state), the reproductive and/ or
do
state achieved.
not enter a
digestive
respond to the environmental stimuli.
both
systems
usually
reproductive
blood
In
dormant
systems
In the far
may
north,
respond with a complete arrest of
and a suspension of
activity
However,
feeding.
latitudes,
for
the stimuli required
delineate the
reproductive
at
both
warmer
diapause may be
sugar and
temperate
achieved with
or without the suspension of carbohydrate
feeding.
Life Cycles.
The occurrence of Culiseta
species over a wide
range of environmental conditions has led to the
evolution of a variety of life history or life cycle
strategies.
Wesenberg-Lund ( 1921) and Bates ( 1949)
classified temperate mosquito life history patterns into
four types based on the number of generations per year
and the mechanism by which the species survives the
adverse period(s).
Frohne ( 1954) later expanded this
classification to account for the unique life history
Text of a presentation in a Colloquium entitled," Overwintering in mosquitoes of medical importance," at the 18th
Annual Conference of the Society of Vector Ecologists, November 20, 1986, Riverside, CA.
2Funded, in part, by research grant AI-3028D from the National Institute of Allergy and Infectious Diseases,
Biomedical Research Support Grant 5- S07-RR-05441 from the National Institutes of Health, and by special funds
for mosquito research allocated annually through the Division of Agriculture and Natural Resources, University
of California.
Berkeley, CA 94720, USA.
pattern
life
appear
life
type of
None
five
is
I,
cycle
exemplified
and
univoltine
overwinters
species,
above the water
gravid and parous females typically appear during late
summer and early fall before larvae or males can be
as
holes.
tree
Cs.
subspecies,
egg
line. Morris
morsitans
laid
Conversely,
the laboratory
above
the
1976) felt that in New York
et al. (
collected
in
if
autumn
most
overwintering in subterranean ground pools associated
with root mats.
Life
IV,
by Culer pipiens, is
characterized by mosquitoes which are multivoltine and
cycle
exemplified
hibernate
as adult females.
Culiseta inornata is
multivoltine and aestivates and/or hibernates as adult
diapausing eggs,
during winter
is dry, the eggs will
larvae
Cs. inornata
of life cycle in the eastern United States, typically
females, depending upon temperature. In the northern
latitudes, Cs. inornata overwinters as hibernating
remain viable
hatch
addition,
Life cycle III, exemplified by Anopheles claviger,
is characterized by mosquitoes which overwinter as
hibernating larvae. Culiseta melanura exhibits this type
larvae
allowing overwintering in the egg stage;
however, if the eggs are inundated by fall rains, they will
In
artificial or natural containers.
overwintered as
morsitans
Siverly ( 1967)
Indiana. Apparently,
whereas
nature.
frequently oviposits in ground pools and rarely utilizes
dyari,
morsitans
also are placed
rafts, which
oviposits
survive
resistant eggs, which are
line in
is
resistant eggs.
Whitman( 1968) found that in
American
State Cs.
summer aestivation by the adult females. In California,
which
drought
diapausing,
drought
as
Further research is necessary, however, before
species
caspius,
Marshall ( 1938) reported that in Europe Cs.
water
litter.
by Aedes
overwinters
Aedes
by
exemplified
multivoltine
adverse periods as
the
could remain viable out of water for 72 hours under leaf
found in
II,
by
characterized
and
during summer in Texas after inundating the litter of dry
tree holes.
They also demonstrated that the egg rafts
eggs.
cycle
569
this mechanism can be accepted as an alternative to
North American Culiseta
into Life
which
diapausing
singly
Wallis
of the
possible
cycle pattern.
of the
were classified
Life
the
Some species, such as Culiseta
possibly Cs. inornata utilize more than
and
cinereus,
Members
four of
to exhibit
TABLE 3).
cycles(
morsitans
one
Alaskan Culiseta.
of several
Culiseta
genus
BULL SOC VECPOR ECOL.
1987
DECEMBER,
females and is active throughout summer ( Hudson
of
1977), while in southern latitudes, Cs. inornata females
overwintering, thus, exhibiting the Type III life cycle.
Certainly, a species which overwinters as drought
aestivate in summer and remain reproductively active
the
and
resistant eggs
resulting
in the form
of a raft
is
are
capable
quite unique
among
This
during winter ( Barnard and Mulla 1978a).
remarkable plasticity will be considered in detail later in
this
mosquitoes.
Wilkins
and
Breland( 1952)
Breland ( 1949)
were able
to
recover
Buxton
presentation.
and
The collection of adult females prior to males or
Cs. inornata larvae
larvae during spring indicates that Culiseta minnesotae
and
TABLE 1. Classification of mosquito dormancy( modified from Mansingh 1971).
HIBERNATION:
Any low
AESTIVATION:
Any
temperature arrest
ATHERMOPAUSE:
high temperature
Arrest not related temperature
arrest
I
I
QUIESCENCE:
OLIGOPAUSE:
Unprepared
Partially prepared response
but long-lasting adversity
response to short- term
adversity
I
I
reduced
to mild
arrested at
Prepared response to harsh and
long-lasting adversity
I
I
REPRODUCTIVE:
Follicles
DIAPAUSE:
I
METABOLIC:
Stage I,
blood- feeding avidity
Reduced blood and sugar feeding,
survival dependent upon hyperthrophic fat
570
DECEMBER, 1987
Distribution of the genus Culiseta in America north of Mexico ( summarized from Darsie and
TABLE 2.
Ward 1981).
Species
Distribution
Subgenus Climacura
melanura (
Coquillett)
Eastern United States
Theobald)
Northern United States and Canada
Northern United States and Central Canada
Subgenus Culicella
morsitans (
Barr
minnesotae
Subgenus Culiseta
alaskaensis (
Ludlow)
Rocky Mtns. of United States and Canada
impatiens ( Walker)
Northern United States and Canada
Western United States and Canada
United States and Western Canada
Pacific Coast of United States and Canada
incidens ( Thomson)
inornata ( Williston)
Adams)
particeps (
and
Culiseta incidens
most
The early spring
females.
light
at
minnesotae
traps
likely
overwinter as adult
being held for more than two and a half months. This
female Cs.
year-long female life cycle must certainly make these
collection
before the
of
emergence of the
Culiseta among the longest lived adult mosquitoes!
first Cs. morsitans in Minnesota led Barr( 1957) to first
consider
Cs.
distinct
as a
minnesotae
In the hot,
arid southwest,
Overwintering by Culiseta melanura.
species.
Cs. incidens
and
Cs.
Because
involvement with the
Cs. melanura and Cs.
inornata are the best studied of the North American
likely aestivate during summer, since
they are plentiful during fall and spring but essentially
disappear from collections during summer, similar to
transmission
Cs. inornata. Barr ( 1985), however, has
of
most
particeps
rafts of
coastal
Cs. incidens during every
California, under the
collected
month of
same
egg
the year in
photoperiod
disappears in the Central
regimens at which this species
These contrasting findings may indicate the
importance of temperature in the induction of
Valley.
Detailed
to
exemplified
Culiseta in Alaska led Frohne
studies of
introduce
by
a
fifth
life
mosquito
Cs. impatiens. As described
cycle,
by Hopla
1970), Cs. impatiens
and Cs. alaskaensis overwinter
have never imbibed a blood meal.
Overwintering females emerge during April and begin
as
females
blood
which
feeding
Oviposition
while
occurs
is
snow
in
May
still
after
on
their
arboviruses,
Culiseta. Detailed studies of the overwintering biology
Culiseta
melanura
have been restricted to the
northeastern United States. Joseph and Bickley( 1969)
collected adults in Maryland from May through
October, but found all larval instars present throughout
the year ( FABLE 4).
Although larval development
appeared to be slowed by cold temperature, the
overwinters in underground sites where photoperiod
was unlikely to be perceived. The month long arrested
mate,
the
would pupate during December when reared under
warm laboratory conditions.
Wallis did not consider
on nectar, and then
August,
remainder of
the Fl progeny from females collected during autumn
photoperiod important because this species typically
during July
for the
from L4 to pupa restricted to spring and summer. These
results suggest a state of hibernation in larval quiescence rather than in diapause. Wallis( 1953) found that
The
relatively rapidly
feed
ground.
progressed slowly throughout winter with the transition
and emerge
mature
and
the
snow
resulting larvae
aestivate
of
persistence of all instars suggested that development
aestivation.
1954)
of
melt.
summer.
Males die
growth
achieved
by
fourth instar larvae reared on
but the female progeny of the spring generation
enter an obligatory winter diapause, which is mandatory
for the initiation of blood feeding the following spring.
alfalfa pellets was attributed by Wallis( 1962) to dietary
deficiencies, which were rectified by the addition of
Even
runoff could add nutrients to breeding sites triggering
out,
under warm
found that females
laboratory
conditions,
would refuse
Frohne ( 1953)
to blood feed
until after
liver powder. In nature, the vernal thaw and associated
pupation;
however, carefully designed
studies to
verify
DECEMBER,
BULL SOC. VECIDR ECOL
1987
TABLE 3.
Life cycles exhibited by the genus Culiseta in American north of Mexico.
Life
I.
Aedes
cinereus
II.
Aedes
caspius
Anopheles
Dormant
Stage
Life Cycle Type'
III.
571
Culiseta
Species
Period
none
egg
claviger
larvae
winter
morsitans
summer
inornata ??
winter
melanura
morsitans
IV.
Culex
females
pipiens
winter
minnesotae
inornata
incidens
inornata
summer
particeps ??
incidens
V.
females
Culiseta impatiens
summer/ winter
impatiens
alaskaensis
Classification scheme after Wesenberg-Lund ( 1921) and Bates ( 1949) as modified by
Frohne ( 1954).
TABLE 4.
Seasonal abundance pattern of Culiseta melanura in Worchester County, Maryland, 19651966 ( from Joseph and Bickley 1969).
Months
Egg
1st
2nd
3rd
1965- 1966
Raft
Instar
Instar
Instar
4th
Instar
January
February
March
April
May
June
July
August
September
October
November
December
Not Present, *=
Few, **=
Moderate,
and*** =
Abundant.
Pupa
Adult
Adult
Males
Females
572
hypothesis have
this
been
not
Alter-
diapause had been induced.
faster
Interestingly, a control
group reared from L1 to adult at 12L and 10°C did not
spring
enter diapause and matured follicles normally with a 10/
Culiseta
2° follicular ratio= 2.72. The requirement for the abrupt
shift from 16L to 12L photoperiod to induce diapause
was difficult to interpret, since a similar photoperiod
performed
natively, pupation could occur as a result of
larval feeding rate associated with warm
a
temperatures.
Hibernation
and
Aestivation
by
inornata.
Considerable
describing
both
inornata.
In
colder
inornata
is
active
adult
reared the
latitudes
during
winter (
Hudson
of
16L
transferred
to
a
12L
as
Hudson
laboratory
strain
under summer conditions
larvae
and then transferred the
regimens
experimental
Cs.
altitudes,
hibernates
1977a).
Edmonton, Alberta
Cs. inornata from Ll to L4
20°C
higher
summer and
of
and
and
transition in nature would occur gradually over several
months. The data of Dow et al.( 1976) in Weld County,
Colorado, suggested that a reproductive diapause may
not be achieved in nature. Resting females collected in
March were either porous or gravid, and empty
nulliparous females could not be collected until May
when the Fl progeny of the overwintering cohort
expended
dormancy in Cs.
winter and summer
females in
1977b)
has been
effort
research
in Figure
shown
photoperiod,
1.
pupated
Temperature had little
diapause
attenuated
condition.
When
were typically empty or freshly blood-fed nullipars.
In the Sacramento Valley of California, Meyer et
al. (
1982a) collected host-seeking female Cs. inornata
oogenesis
indicating
effect upon the
Blood
was
that
induction
feeding avidity
a
In contrast, the first Cuiex
emerged
rarsali<s females concurrently collected during spring
I and the ratio of the primary to the
length was less than or slightly above
follicle
secondary
1. 5 two weeks after emergence; significantly different
from larvae allowed to pupate and emerge at 16L( Fig.
1).
and
to the
arrested at stage
the
DECEMBER, 1987
from September through April with peak abundance
during fall ( Fig. 2). Larvae first appeared in
October ( Meyer et al. 1982a,b).
occurring
of
We have found a similar pattern in the southern
also was
San Joaquin Valley with a dramatic decrease in the
winter
abundance of host-seeking females at CO2 baited traps
reproductive
3. 5—
3. 0—
14- 15 Days
—
Days Postemergence
7- 8 Days
2. 5—
1111111111111
111111111111
o
ss
111111111111
1. 5—
IIIIIIIIIIII
0.5—
A A
0.0
Temp(° C) =
10
Hours L:D=
Figure 1.
15
4
Ad
4,
20
10
12: 12
A.
15
20
16:8
Mean primary/secondary follicular length ratios for Culiseta inornata females ( Edmonton
laboratory colony) 7-8 days and 14- 15 days postemergence. Females were reared from ecolsion
until fast pupation at 20°C and 16L:8D and then transfemed to the experimental regimens
presented ( plotted
from data
presented
by
Hudson 1977b).
DECEMBER,
during
observed
abundance
by
presented
from
Fig.
summer and midwinter (
pattern
Washino
Washino
1962) for
et al. (
et al. (
1962)
This
Fig. 3).
Females collected from shelters in Kern County
by Washino et al. ( 1962) did not exhibit a reproductive
The
arrest during either summer or winter ( Fig. 6).
different from that
somewhat
abundance
where
shelters
4).
was
was
adults collected
highest in
collected
larvae
single female collected during August
Collectively, CO, trap and metabolic
indicated that in California Cs. inornata
undergoes ieyiuductive quiescence during
May
during
every month of the year except August and September,
however, male abundance at shelters did not increase
until
markedly
consistent
the
populations
when
vernal rise
midwinter
activity
rather
night
than the
Abundance
patterns
Thus, the
abundance
by CO,
have
may
of adult mosquitoes present
similar
abundance.
monitored
were
light trap catches
depressive effect of cold
Jersey
adult
in
decline in
decrease in
in the
Jersey
insectary(
numbers
photoperiod
regimens
25° C)
and a cold
building(
16° C). Fach box
source. The progeny of females collected by CO, traps
during April were reared from eclosion to emergence at
five photoperiods and two temperatures( Fig. 7). Adults
in the Coachella
Valley were
Valley except that
were held under the test regimens for two weeks postemergence, after which 10 to 15 females were dissected
and the length of the primary and secondary follicles
Fig. 5).
abundance (
and
was fitted with its own timer and 25 watt bulb light
midwinter
light trap
temperature
produced in a series of light boxes held in a warm
on
nightly temperatures did not
catches and an early vernal
depress
trap
markedly
temperature rise resulted in an earlier decrease in New
warmer
winter.
experimental
the
environment.
to those in the San Joaquin
was gravid.
status data
most likely
summer and
To verify field observations, we studied the
response of Cs. inornata
from Kern County to
New
reflected
time temperature
actual
perhaps
observed
or
573
SOC. VECIDR ECOL
BULL.
1987
350
Coastal Marsh
300
Sacramento Valley
250
x
x
Sierra Foothills
man
z
a
200
150
a
Z
100
+
50
jn{
No Samples
\
74x +
O
N
D
J•
M
A
M
J
J
A
S
O
N
D
J
F
M
A
M
1977
1976
1975
Figure 2.
F
Relative abundance of host-seeking Culiseta inornata ( females/CO, trap night) at three rural
habitats in
central
California, 1975- 1977 ( redrawn from Meyer
et al.
1982a).
574
DECEMBER, 1987
80
O
70
60
z
50
F-
40
a
30
t
20
10
0
0
D. • • • •
0
0 - CI • • • • • • •
J F MAM J J A S O N D J F M AM J J A S O N D J F MA MJ JA SOND
1983
Figure 3.
Relative
1984
abundance of
1985
host-seeking Culiseta inornata (
females/CO2 trap night) at the Kern
National Wildlife Refuge, San Joaquin Valley, California, 1983- 1985 ( unpublished data).
Neither
measured.
anested
markedly
diapause
reproductive
temperature
follicular
nor
maturation,
not
was
photoperiod
indicating
induced
under
midwinter or midsummer photoperiod and
degeneration.
either
In Kern County, the first females collected during
temperature
Mean primary/secondary follicular ratios
1. 95 and did not vary significantly
conditions.
ranged
matured to the resting stage after the initial
that
the fall of 1986 were either parous or gravid
(
1. 64 to
throughout.
Since
experiment
placed
in
data
of
Hudson( 1977b) indicated that
a
fourth instar
was
induce diapause, we repeated
using field collected LA larvae which
our
photoperiod
during
to
necessary
reared
the
in
transition
nature under
in the
11 to 12 hours
same experimental
Figure 7. The follicular
of
light
regimens
were
unpublished data), indicating that some females take a
blood meal prior to aestivating and remain gravid until
fall when they emerge and oviposit. These field data
were similar to the spring observations of Dow et al.
(
1976) in Colorado and supported our laboratory
experiments, which indicated a lack of reproductive
diapause.
Meyer
1982a) have shown that Cs.
et al. (
and then
inornata females are facultatively autogenous and that
in
the proportion of autogenous females increases during
winter as a function of decreasing temperature.
shown
decreased significantly to
less than 15 under conditions of 10 to 16L at 16° C.
However, most ovarioles in these groups possessed
Therefore, some of the gravid females collected during
degenerative
eggs autogenously without imbibing a blood meal.
endocrine
ratio
dilatations
indicating
activity, which is not associated
diapause.
Most likely the
reproductive
primary follicles
were small
continued
with a
size
because they had
of
true
the
not yet
spring, but not late summer, may have developed their
Although
reproductive
females
diapause,
physiological preparation
may
they
for
not
undergo
a
may
undergo
a
aestivation
by depositing
DECEMBER,
575
BULL SOC. VECDDR ECOL
1987
400
300
8
Males
x
x
p
o
Females
a
200
o
3
V
4
100
Z
0
o
is
X
x/
x
x
x
x
x\
°
x/
0
Figure 4.
M
A
M
F
J
D
N
0
S
A
J
J
Relative abundance of resting Culiseta inornata ( total males and females collected resting in
shelters during each month), Kern County, California, 1952- 1961 ( plotted from data presented
by Washino et aL 1962).
2. 5
x
x
z
Males
a
2. 0
Females
E--.
t)
1. 5
p
r
o
p
o
1. o
z
0.5
z
x\
.
0
x/
0.0
gyp\
x•
x
_
J
F
M
A
M
J
J
A
1975
Figure 5.
S
O
N
D
I
P
M
A
M
J
J
A
S
O
N
D
J
1976
Relative abundance of phototactic Culiseta inornata ( log10[ y+ 1] adults/New Jersey light trap
night),
Coachella
Valley,
California, 1975- 1976 ( redrawn from Barnard
and
Mulla 1978a).
576
BULL SOC VECIDR ECOL
Unfed
100—
—
—
—
—
DECEMBER, 1987
Blood Fed
Gravid
—
90
80—
70—
60
a
—
50—
r
40 —
10—
11.
0
Jan
Figure 6.
Feb
Mar
Apr
May
Jun
Jul
Aug
Oct
Sep
Nov
Dec
Metabolic status of resting Culiseta inornata females collected at shelters in Kern County,
California, 1952- 1961 ( redrawn from Washino et al. 1962).
2.0 —
V
1. 5 —
1. 0 --
0.5
0.0
Temp (° C)
25
Photoperiod
8L: 16D
Figure 7.
16
25
16
1OL: 14D
25
16
12L: 12D
25
16
14L: 10D
25
16
16L: 8D
Mean primary/secondary follicular length ratios for Culiseta inornata females from Kern
County, California, which were reared from ecolsion to emergence and then held for 13- 15 days
postemergence at the temperature - photoperiod regimens presented in the figure( unpublished
data).
DECEMBER, 1987
577
70-
60-
50-
40
3
30—
20-
10—
f.
r
S
O
N
D
J
F
M
A
M
J
J
A
S
5
33
214
48
81
56
29
19
12
4
0
0
4
N=
1975
Figure 8.
Lipid
O
N
D
J
47 183
61
43
1976
F
29
1977
by weight) of Culiseta inornata females collected by New Jersey light trap
content(%
in the Coachella Valley, California, 1975- 1977 ( redrawn from Barnard and Mulla 1978b).
hypertrophic fat.
Observations
1978b) in the Coachella
increase in the lipid
Jersey light
by Barnard and Mulla
Valley indicated a three-fold
content of
females
collected
in New
during March-June( Fig. 8). Females
disappeared during July and August and those collected
at
light
traps
traps
in September
fat
their preaestival
Barnard
and
and
October had depleted
reserves.
females,
of
rates
blood-fed
and nonblood- fed
indicated that the mechanisms
for fat deposition were independent of
which
responsible
factors controlling reproductive activity. All blood-fed
females developed their eggs normally and did not
exhibit
cribed
gonotrophic
for
some
dissociation
Culex
and
similar
that des-
to
Anopheles.
Thus, Cs. inornata from California do
either
a
winter
Aestivation
is
or
summer
reproductive
accomplished
quiescing females,
which
fed or gravid females can be collected during every
month. However, Culiseta inornata does respond to
photoperiod cues during early summer and prepares for
aestivation by depositing hypertrophic fat. During late
July to early September, females essentially disappear
and have yet to be collected in large numbers in natural
Mulla ( 1977) demonstrated in the
laboratory that fat deposition was induced by
lengthening photophase independent of temperature
Fig. 9). Of considerable interest was the comparable
lipid deposition
Host-seeking continues throughout the year and blood-
not enter
diapause.
by reproductively
may be
gravid
or
parous.
or artificial shelters, CO2 or New Jersey light traps.
Survival during the hot weather is dependent upon fat
reserves,
which
are
accumulated
regardless
of
reproductive status. Although induced by photoperiod,
aestivation is rapidly terminated by changes in
temperature and during midsummer in Kern County
females can be collected host seeking at CO2 traps or
resting in shelters.
The decrease in abundance during midwinter is
difficult to explain. Larvae, pupae, and newly
emerged adults can be collected at breeding sites
throughout winter. However, cool evening temperature
during winter reduces host seeking and dispersal
more
activity and few females can be collected in red boxes or
host seeking.
Adults
can
be
collected
from
rodent
DECEMBER, 1987
578
70 -
Nonblood-Fed Females
Blood-Fed Females
60 —
50 -
40 -
30 -
10 —
o
Lipid
content(%
reared
from
25
20
15
25
20
15
25
16L:8D
8L: 16D
16L: 8D
8L: 16D
Photoperiod
Figure 9.
20
15
25
20
15
Temp (° C)
by weight) of blood-fed and ruffed Culiseta inornata females which were
eclosion
to emergence and held at the temperature -
photoperiod regimens
presented in the figure for 21 days after emergence. Females were offered 10 percent sucrose
or a restrained chick on days 6- 15 ( redrawn from Barnard and Mulla 1977).
burrows
on
warm
Apparently,
1978b) found
no winter change
reserves.
Thus,
winter
in the
is
there
for this weakly
quiescence, since Barnard
transient winter
lipid
days.
preparation
physiological
no
maintained,
and
Mulla
accumulation of
dormancy
in Cs. inornata
Barnard, D. R. and M. S. Mulla 1978a
of Culiseta inornata
California:
The ecology
in the Colorado Desert of
seasonal
abundance,
gonotrophic
of adult mosquitoes.
status and
oviparity
Entomol. Soc. Am. 71: 397-400.
Ann.
must be classified as a cold weather quiescence.
Barnard, D. R.
Acknowledgements
I thank Drs. W. C. Reeves
suggestions
this
of
and
R. P. Meyer,
California, Los Angeles,
and comments
during
for helpful
the preparation
of
REFERENCES
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photoperiod
CITED
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Barr, A. R.
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Morris, C. D., R. H. Zimmerman, and L. A. Magnarelli.
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Diptera: Culicidae). Ann. Entomol. Soc. Am. 69:
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101- 105.
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R. E.
abserratus
Frohne, W. C.
1954.
Mosquito distribution in Alaska
to a new type of
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Felt
(
The occurrence of Aedes
and
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melanura ( Theobald) in Indiana Mosq. News 27:
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Hopla, C. E.
The
1970.
natural
history
of the genus
Wallis, R. C. 1953. Notes on the biology of Culiseta
melanura ( Coquillett).
Mosq. News 14: 33- 34.
Culiseta in Alaska Proc. NJ. Extermin. Assoc.
57: 56-70.
Wallis, R. C. 1962. Overwintering Culiseta melanura
larvae. Proc. Entomol. Soc. Wash. 64: 119- 122.
Hudson, J. E. 1977a. Seasonal biology of Anopheles,
Culex
and
in
Culiseta
central
Ph.D. Diss.,
Culicidae).
Alberta ( Diptera:
University
of
Alberta,
384 pp'
Hudson, J. E.
melanura
1977b. Induction
of
diapause in female
and
(
W. E.
Bickley.
Coquillett)
on
1969.
Culiseta
the eastern shore
Maryland ( Diptera: Culicidae).
of
Univ. Maryland
Ag. Exp. Sta. Bull. A-161: 1- 83.
Mansingh, A.
and
1968.
L. Whitman.
Oviposition of
Culiseta morsitans ( Theobald) and comments on
the life cycle of the American form. Mosq. News
mosquitoes, Culiseta inornata, by a decrease in
day length. J. Insect PhysioL 23: 1377- 1382.
Joseph, S. R.
Wallis, R. C.
1971.
A
physiological classification of
dormancies in insects.
Can. Entomol. 103: 983-
28: 198-200.
Washino, R. K., R. L. Nelson, W. C. Reeves, R. P.
Scrivani, and C. H. Tempelis.
Culiseta inornata
encephalitis viruses
as
a
1962.
possible
in California.
Studies on
vector
of
Mosq. News
22: 268-274.
Wesenberg-Lund, C. 1921. Contribution to the biology
of the Danish Culicidae. Mem. Acad. Roy. Sci.
Ltrs. Copenhagen, 210 pp.
1009.
Marshall, J. F. 1938. The British Mosquitoes. London:
Brit. Mus. ( Nat. Hist.), 341 pp.
Wilkins, O. P. and O. P. Breland. 1949. Recovery of the
mosquito Culiseta inornata
from dry material.
Proc. Entomol. Soc. Wash. 51: 27- 28.
BULL SOC VECIOR ECOL, 12(2): 580-583
DECEMBER, 1987
FUTURE OPERATIONAL CONSIDERATIONS'
R. D. Sjogren2, D. J. Dobbert2, and S. Palchick2
Accepting
an
invitation to
future directions in
speak on the
is
broad topic
computer use in operational programs has occurred
a presumptuous
with people who in the past 20 years have moved from
The senior author speaks from a
undertaking.
background of 26 years experience in vector control
pencil and paper data management, through hand-held
of
programs
technical
vector control
Academic training,
literature, in- house research, the insights and
of
experience
intuition have
Directing
and
co-workers,
provided the
control
programs
extent on" seat of the pants"
However, it has
in the field
of
specifying basic
data
of
for
framework,
for independent
a
operational
quality
Data
Statisticians and data analysts have long advised,
"
See me before you do the work, not after"; so it is with
the collection of data to be managed by computer.
Future problems can be avoided by first consulting with
an individual knowledgeable in data analysis and
research design, before you begin collecting data.
vector
Unless the error rate of the data is known and reduced to
a level acceptable for future decision making, the value
models
data
data,
and analysis.
with all aspects of an
of
Within
be
control program can
reliable
acquisition
to be answered and the data necessary to adequately
management to
reliable communication.
assessment of
With
considerations
is
play in data
answer those questions.
experience.
the
In most instances,
computers.
collection procedures should be shaped by the questions
many
These extend from
control.
vector
control
years,
of
to
appreciation of the critical role that planning and quality
of
encompasses
dynamics. Intertwined
performed.
with
kept up with the current state
information management
requirements
effective program
this
intuition. Over the
information
this
utilizing
measure
now
people just entering the computer era have little
basis for decision making.
has depended to a great
management
integral to
population
good
not
Information
areas
a
has broadened
the " seat of the pants"
art
calculators,
in the United States.
Collecting high quality, relatively error free,
operational data by field staff while they are doing the
collected and work
we can
for the future from
and effort expended to collect the data will be lost
used
further
address
work
is
a
difficult
task.
Few operational programs
recognize the care and precision with which the data
a philosophical and
must be collected. This problem is compounded by the
viewpoint
fact that field staff are expected to gather data while
Data
Management
performing their necessary duties.
Mere intuition is insufficient to
Good data management comes at a price.
contend with the
technology,
Pretending that computer utilization will enhance
complexity of multifaceted control programs,
increased focus on potential environmental impacts and
program operations, without paying the price, will
rapid
advancement of personal computer
the
requirements,
monitoring
accurate
field
of
data
and
the
collection with which to
operations.
Intuition
must
be
importance
relegate computer utilization to only an image of a
of
progressive operation.
scale
quantifying and tracking data input on each program
by
state
activity cannot be overemphasized. It is the only way
augmented
the art data management procedures capable
that future cost effectiveness analysis can be conducted
of
providing quantitative data on which to base costeffective day- to-day program decisions.
High quality data
management practices
required to take advantage of, and
advances
in
vector control
managers recognize the
advancing
Presented
field
at the
of
keep
computer
offered
will
Communication and Quality Control
It is impressive how accurately communication can
be
pace with, the
technology. Most
benefits
The importance of accurately
direct large
by
science.
18th Annual Conference
convey the work needed and, with conscientious
application, produce the results needed. However, it is
program
the
rapidly
not realistic to assume that communications retain their
Extended
intended meaning as they pass from program directors
of the
Society
of
Vector Ecologists,
University
of
November 19, 1986.
2Metropolitan Mosquito Control District, 2380 Wycliff St., St Paul, MN
55114,
U.S. A.
California,
Riverside,
DECEMBER, 1987
supervisory staff down to
difficult to ascertain that they
and
Foremen
hence they
are
often
often are not
programs has come under increased public scrutiny in
readily
for
do
jurisdiction,
their
discuss the
Unless
staff.
addressed, problems often
but
accuracy and environmental impact of vector control
to
reluctant
field
their
of
quality
Concomitant with operational concerns, the
committed to paper.
of
areas
quality assurance program.
understood and
and supervisors are responsible
going correctly in
things
be
will
accurately interpreted, even when
These gaps in communication
perceived.
It is
seasonal workers.
581
not surface
specifically
for resolution,
lack
rather compound over time through
work
of
feedback
recent years. We have recently been directed to prepare
our
second
Environmental
our
concerning
control
Impact
program.
Statement
Vector control
districts should not be surprised if they too are faced
with
this
Availability of a reliable data
responsibility.
base can facilitate this task.
communication.
One
for this lack
solution
is
staff
to
open
communication
and
and
of
feedback from field
maintain
channels
between
accountability
field
Mother
operations staff and program administration.
solution
is
to conduct a concunent
program to confirm that
field
manner that the program
director
the
implement
personnel understand and
the managers as
science of
its
intended.
in
own
anticipates.
can confirm
school or
love
their
ongoing
Over the
field.
experience
and
modeling principles can be used becomes more
available and widely understood.
The value of modeling depends upon the intended
the
model
the user.
and
Graphic models
with
illustrate components and relationships of processes or
in early
adulthood after
high
systems.
Due to
working in the
make a career out of
such
years
for
began working
the summer months of college.
stay to
people often
an
modeling.
vector
the outdoors and interest in the work, these
of
gain
staff
operational
during
to
The application of modeling in vector
control will increase as the understanding of how simple
of
uses
vector control programs
researchers
processes, and by entomologists for insect population
programs.
Most field
science
field
that
Qkility assurance is a mature
Quality
control professionals can offer much to
control
natural
Secondly,
manufacturing field.
the
operations,
understanding of biological, physical, and chemical
directives
the
Systems modeling has been used for some time by
defense contractors for weapon systems development,
NASA for the space program, management for business
in the
personnel perform
assurance program
quality
assessment
quality
Vector Management Model
of
intuition
develop
staff
on
to
what
extensive
expect
when
Computer simulation models allow program
leaders to look into relationships which may have a
significant impact on the end result
The primary value of modeling is the opportunity to
examine how the system behaves without the cost of
actual
implementation.
While identifying the
As programs
changing conditions are encountered.
increase in size, a larger percentage of the work force is
components and their relationships, the model builder
composed of seasonal
are raised and their answers lead to further questions and
clarification. Unclear areas are identified.
direction
ranks.
Operational
The
work
to
programs
and experience
working
come
depend
the
up through the
the transfer of
How accurately the model visualizes the real life
situation determines the quality of the model. Whether
nature of vector control operations requires
be
many geographic areas at the
It is physically difficult to verify that the
performed at
work
acceptable
performed
standards
of
by
each
gains insight into the process being modeled. Questions
older staff to the
on
from the
under
employees.
same time.
field
have
of older staff who
knowledge
seasonal
employees
employee
implementation.
programs require control materials to
be
meets
Advanced
used at more
the model provides insights into questions it was
designed to address determines its usefulness.
The
model is never true, false, complete, or incomplete; it is
only in a state of usefulness. This means a model must
be updated regularly as the questions it must address
change, the real life situation it depicts changes, or
further insight into the situation it depicts becomes
minute levels with accurate timing and delivery.
The
opportunity for failure to communicate in sufficient
available.
detail
Future
increases
and
the
consequences
of
errors
compound.
It is difficult to know
conditions
over
independent
large
assessment
control procedures.
Metropolitan
what
is
being done under field
geographic
of
the
areas
without
an
which
implementation
of
administrative
This information is
Mosquito Control
Considerations
While consolidation is seldom a popular topic, it is
difficult to argue against the regional control concept in
collected
District
for the
through
a
a
unified
program
canopy.
operates
under
one
Insect populations, especially
migratory populations, do not recognize political
boundaries.
M effective
vector control program must
by artificial
projects are conducted in prominent residential areas
A properly designed regional program can
where
technical
support
increased
and if reports comparing mosquito biting levels inside
insects
go where the
constraints.
provide
is
specialization
are and not
in
needed
the insect
flight
Under
such circumstances,
which
best be done
disease
for
It is less
by
Too
cost.
over
long
the
and
it
when
term
operations. In Minnesota, such specialization has been
control,
successful
in Coquillettidia perturbans
Similium control, LaCrosse Encephalitis vector control
to
prior
body,
and
clearly
agency
to their
marketed
them, and what
begin vaguely
Effective
desired
lower
control
vector
by
the
to pay for the
willingness
greater
pay
i.e.
it
will
and continue
based
surveys,
the
perceive
accurately
significant
annoyance
problems
projects conducted
in
to a decision- making
In the
achieved.
adjacent areas. Such efforts largely relegate the control
cost and
possibly
by
received,
their
be up to five times
to
one to
two
program
readily
is
on
control
measures will shift increasingly to a preventive rather
than a reactive program. These operations may require
by
are
body
disease transmission
present,
doing
demonstrate
control
all
the
significant
and within the mosquito developmental period
Preventive control measures, which employ
prehatch and long term controlled release formulations
of
environmentally
compatible
control
materials,
allow each employee to treat up to eight times more area
than with previous methods. Altosid controlled release
briquets and Altosid controlled release sand granules
unrealistic
goals.
to expect
will
support
Where
program
programs
running
be effectively used to demonstrate
The program effectiveness can be
if
to
be
on the word of program
citizens
resources
so, the cost per unit
administrators
based
or
demonstration
that effective control can
demonstration
by
focus
mosquitoes,
desired
service
years can
understood
operations
Aedes
of
the program
benefits.
of
level
process of
needed,
control
broods
substantial
being convinced of the program
and knowing what the ultimate cost will
achieve
vector
breeding grounds within the flight range of the species
values
without
expansion
Where
synchronous
to
be determined. It is
be
the next flooding.
When
boards
officials
effectiveness
When you' re
for favored
that
staff,
approach."
needed, you' re needed; and when you' re not, you await
afforded
worse case areas can
expansion of programs,
firehouse
activities
governing
vector
or
to a "
services
help
area can also
elected
the greatest extent possible with available
infiltration of adult mosquitoes from uncontrolled
taxpayers.
Where
check to
provided
applications.
denied time
on
activities,
control programs largely
to inform
that
service can
Conventional Aeries
await a flooding, which initiates a brood, and in the
succeeding days work feverishly to reach as many
breeding grounds as possible to hold the populations in
being
low
benefits
within the specialized nature of the work.
citizens)
than the service costs to deliver. Willingness- to-
out- of-door
In each
measures.
resources and rarely is capable of achieving control over
a sufficiently large geographical area to counteract the
lack
to
provide
than
pesticide
the
recognize
assurance
programs must
programs
impact
individual homeowner
quality
resources. This approach is a poor use of manpower and
services
general public at a
environmental
citizens
the
of
and
of
due
vector control
customers (
benefits
activities,
staff,
communication.
them of the
A trend will probably develop towards more
simplify the day- to-day decision process in program
to establish goals
identified
support
As in any business,
am answered.
high
vague, undefined objectives,
with
public
without
program
instance, staff responsibilities are regional and remain
will get
often programs
accompanies
will provide increased efficiency and quality, and will
effectiveness
goals are
such
program
to
periods of
common
the
identifying
common
levels to " do something
the policy- making
is going,
program
It is
citizens can everyone understand where the
local
and
placed on
of
effectiveness, the two most frequently asked questions
specialized training of field staff. This specialization
of a program.
when
understood
safety
agency.
during
program' s
a
measuring
implementation
Only
be
programs
annoyance
about the problem."
is
boundaries.
political
vector control programs.
vector
or
and outside the demonstration area are distributed
When information on the environmental
monthly.
long
capable of
a single purposed
vector control
activities
A
the assignment of resources
emphasis needs to
Greater
the goals of
form
by
is
vector
transcends
range
can
restricted
coordinated control
with
important
when
be
vector control programs.
unified program
be
DECEMBER, 1987
582
such
demonstration
afford
significant
operational
benefits
through
advanced applications to highly productive breeding
grounds, thus, making better use of aircraft and ground
crews.
To offset the pressure of controlled release
formulations on resistance development, 20 and 40 day
controlled
release
Bti
formulations
are under
development to mitigate resistance development by
alternating selection pressure.
The focus on
continue
to
increase
environmental
and
draw
aesthetics
vector control
will
programs
DECEMBER,
1987
into
stage
center
information
be
should
educate
associated
considered
control
materials
impact,
and
based
finally
on
cost,
vector
gain
As programs increase in complexity and/or size,
accountability and attention on cost effective program
operations increase accordingly.
When programs
important
public
the
as
of
develop beyond where program managers can track all
nontarget
the pieces, well organized and accurate data sets are
selection
effectiveness,
the
for
necessary to maintain an understanding of field
programs
program decisions. The cost to obtain an accurate data
set must be weighed against the cost incurred from
support
conditions and relationships upon which to base
of
complexity
operational
different
difficult to deter-
with the number of employees and
tasks performed, it becomes
the
real
costs
of
out
accurately,
accept
the
responsibility
native
is best,
In
inadequate data.
ness, we need to
at
procedure
impact
and
for
administrators
guessing
to
laboratory
Such data needs are not unique to vector control
is
programs. We have all heard how rapidly information
management systems are developing in the business
must
outcomes
The
also
world.
Expert systems and artificial intelligence are
with
being applied to decision making and service systems in
effective-
manufacturing, medicine, mental health, education and
cost effectiveness of each
in the field.
making a wrong decision with inadequate information.
and
which alter-
best making decisions
addition
unintended
activity
each program component
determine the
control
control
program
costed
or
more
each
Unless
associated options.
identified.
control
programs.
increases
mine
with
as
public
583
about
citizens
Judicious
themselves.
activities
As
to
Active
review.
public
factors
control
operation
for
programs
environmental
programs
BULL SOC VECPOR ECM
environmental
need
to
be
training,
should
and psychology.
The vector control field
evaluate its direction and consider the
application of
those technologies into its operations.
DECEMBER, 1987
MANPOWER NEEDS IN DISEASE ENDEMIC COUNTRIES1
R. Slooff 2
This
paper
needs of
disease
biology
and
disease
control
endemic countries
imply
that the
other
levels
manpower
be
should
referred
usually
to as
In disease
medical
entomologists
a
country profiles, which were used as working papers
and as a basis for the workshop deliberations. A similar
workshop is being planned for the southeast Asian
Region. It may be held in Thailand in either late 1987
or early 1988, and it will focus on in-depth country
concerned
carried
cycles,
by
Indonesia.
control
and
the
studies to be performed in Thailand, India, Burma, and
of
range
wide
very
duties
Such studies and others already completed show an
of
incrimination,
vector
of
evaluation
alarming situation in many disease endemic countries
control
inasmuch as major disease control programmes either
control
are being directed on the basis of vastly insufficient
vector control expertise or are not even being
of
choice
epidemiology,
or
or at
and control,
zoonoses
include
supervision
strategy,
biology
control programmes,
bionomics,
vector
and
covers
options.
This
Training Needs in the American Region.
workshop was preceded by in-depth studies in Panama,
Ecuador, Guatemala, and Colombia, resulting in
less important
entomology, is
medical
transmission
species,
vector
disciplines
other
of vector
the discipline
vectors,
issues in
diseases
human
all
with
was held in Panama in 1985, on the Manpower and
of
guidance
for carrying out the
This restriction does not
considered
As the speciality
of WHO. Within this collaborative activity, a workshop
the
and
operations
applied research.
necessary
in
for the
specialists
control
manpower
respect of vector
addresses
specifically
implementation, and the monitoring of its impact The
medical entomologist engaged in applied research faces
a multitude of urgent research questions
development, the
pesticide
of
use
biological
agents and environmental control, the
primary health
unexplored
in
care,
field
immunological
tasks
and
methods,
self-protection
addition
of
the
and
challenging
In
rewarding professionally.
entomologist of today is graced
complexity than his
development
wide and
of
endemic countries and in potential donor countries, ( 2)
largely
by
lack of training components in externally financed
manipulation
engineering. These
work can be very
the
general,
medical
with more problems of
colleagues of a generation
projects, (
endemic
of
countries
that
have
are
entomology
instances. Just how
however,
remains
clarify the
this paper suggests,
between
inadequately
largely
disease
in
medical
needs
met
great the unsatisfied
many
demand is,
One
unknown.
in
attempt to
situation and to provide manpower planners
training institutions
guidance
manpower
the
with
data for
more concrete
is
being executed by means of collaboration
the Fogarty International Center, WHO, and
USAID. This
training
project aims at
needs
lack of attractive career prospects in
"
brain drain" to the commercial sector, universities or
research laboratories, and to industrialized countries.
WHO and TDR are involved in several activities
at
the
improvement
of
this
situation.
The
collaboration between WHO and the Fogarty
International Center and US AID was already
mentioned.
More efforts will be needed in analyzing
manpower situations and in encouraging remedies to be
taken by appropriate institutions worldwide. Through
its research capability strengthening and institution
strengthening endeavors, TDR is already contributing
to improvements, particularly in developing countries.
At present, several M.Sc. courses in tropical countries
manpower
receive TDR and/or WHO support ( e.g., in Panama,
endemic regions
Cote d' Ivoire, Nigeria, Kenya, India, Thailand, and
the analysis of
in important disease
3)
disease control or applied research programmes, and( 4)
aimed
As the title
and
their biology, and means of control applicable under
conditions prevailing in the country.
The major constraints for remedying the situation
are ( 1) lack of training facilities, both in the disease
for
ago.
and
considered for lack of information on vector species,
of
control
approaches
to the
or genetic
means
are
greater
other
transmission
in the field
Presented at the SOVE Symposium, AMCA Annual Meeting, Seattle, Washington, 31 March 1987.
2Director, Division
of
Vector
Biology
and
Control, World Health Organization, 1211 Geneva 27, SWITZERLAND.
DECEMBER,
1987
Indonesia),
with
efforts
are
varying degrees
to
needed
assistance provided and
some of
disease
these
vector
research that
National
evaluate
to
of
success.
the
effects
improve the
More
of
control
programmes
the applied
and
to support these.
institutions, both in industrialized
and
developing countries, are already playing a significant
role in bridging the gap between supply and demand in
the
field
input is
of medical
required
entomology, but substantially
Particularly needed are: ( 1)
compatibility between the
training
components
in
programmes carried out
3) raising disease
disease
In reviewing the situation, the most acute needs are:
more
more
(
1)
in- country situational analyses to clarify the
manpower
and
training
needs
worldwide, (
2) the
establishment of regional M.Sc. training programmes in
disease endemic countries, ( 3) achieving improved
international compatibility in specifications for and
standards of M.Sc. qualifications, and ( 4) improvemeats in career prospects for medical entomologists,
particularly in disease control programmes.
discipline
Medical entomologists should be more multi-
vector control, ( 2)
functional within a wide range of vector and pest control
academic research
and the operational needs of
postgraduate levels.
adjustment of
courses to meet the needs of
is necessary
recognized specialization at the M.Sc. level and at
the
training
585
research
and have a profound understanding of epidemiology, in
in disease
endemic countries,
order to be able to adapt to the needs of different posts
biology
to the status of a
and the problems raised
vector
vector
control
and
by
changing disease
priorities.
ADVERTISING
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from the advertiser' s unauthorized use of any name,
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or
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INVITATION TO CONTRIBUTING AUTHORS
The Bulletin
search, or
the
publishes
results
review thereof, and
from
presentations
national or
of
original
new,
invited
Bull. Soc. Vector Ecol., 9( 1):
re-
Soc. Vector Ecol., 9( 1):
and submitted
local SOVE
quired for review presentations; when and where ap-
proceedings
propriate, a REFERENCES CITED section and textual
biology and control and related
disciplines. Submitted manuscripts are acceptable in
English, French, Spanish, Italian, or German. Foreign
in the field
of vector
headings and subheadings are recommended; an Acknowledgements section is optional. The Invitational
and Submitted Presentations manuscripts are reviewed
English summary,
An original manuscript typed and double- spaced, plus
two complete copies must be submitted. The copies will
language
be
manuscripts must
to at least two
sent
that the
include
an
outside reviewers.
contributions are
based
It is
30- 36; Reisen, 1984, Bull.
6- 16). An ABSTRACT is re-
and edited for style, typographical errors, and syntax.
There are no page charges for Invitational Presentations
published in the Bulletin; page charges are $ 25 per
printed page for Submitted Presentations.
assumed
on original research that
has not been submitted for publication or published
elsewhere.
Manuscripts
of
current style
in this
Manual
Edited
Council
of
Instructions),
Biology
changes
to the
Submitted Papers:
found
These articles are contributions from vector biologists at large that are sent to the Bulletin for publication
and represent original research( see Mulla and Darwazeh,
generally
Editors ( CBE) Style
which
Edition. AIBS, Washington, D. C.
4th
1979,
1984, Bull. Soc. Vector Ecol., 9( 1):
articles that thoroughly cover some aspect of vector
galley proof drafts, and galley proofs
to the corresponding author in order to
editorial questions before final printing.
biology ( see Balashov, 1972, Misc. Publ. Entomol. Soc.
reviewers'
comments
pre-
Types
any
of
Vector Ecol., 6: 1- 92). Research Notes represent original
research and are no more than two printed pages in
length( see Bennett, 1983, Bull. Soc. Vector Ecol., 8( 2):
139- 140). Submitted Papers are evaluated by the referees for originality, pertinence, and presentation of the
Articles
Proceedings:
Proceeding' s
articles consist of
Invitational
and
Sub-
subject material in addition to style and form. Page
f., Submitted Papers) from SOVE
Regional and National Conferences and may be historical
reviews( see Gerber g' 1984, Bull. Soc. Vector Ecol., 9( 1):
mitted
Presentations(
c.
charges are $ 25 per printed page. See the INSTRUC-
TIONS TO CONTRIBUTING AUTHORS section in the
Vol. 10, No. 2( December, 1985) issue of the Bulletin for
27- 29; Hess, 1984, Bull. Soc. Vector Ecol., 9( 1): 23- 26),
or
research
specific
articles ( see
Mitchell
et
al.,
160- 376; Rvckman et al., 1981, Bull. Soc.
Am., 8( 5):
returned
resolve
51- 58), or synthesis
when
manuscripts ( with
appropriate),
are
the
of
revision
follows the
are edited with reference
the Bulletin( allowing for
more information.
1984,
Send manuscripts to:
Bulletin of the Society of Vector Ecologists
Dr. James P. Webb, Jr., Editor
Orange County Vector Control District
13001 Garden Grove Blvd.
Garden Grove, California 92643
Reprint Price List
Pages"
Copies
1-
50
Each
addl.
same
a
For
more
45. 50).
50
5-
4
9-
8
13 -
12
16
17 -
20
45. 50
90. 00
135. 00
180. 00
225. 00
5. 75
11. 50
17. 25
23. 00
28. 75
order)
than
twenty( 20)
pages, combine
the
rates( e.
g., 24
pages=
20+
4, i. e., for 50 copies the cost is$ 225. 00+

Volume 12, Issue 2, December 1987

Transcription

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