Missouri`s rare Prairie Butterflies

mDC PhOtO
Missouri’srarePrairie
regal fritillaries, which may travel
for miles across a good-quality
prairie, will not travel even a few
feet to cross a road if proper habitat
is not available on the other side.
0
Butterflies
By Phillip E. Koenig
A
s a child, I was fascinated by butterflies, and this
fascination has never waned. Although I went on
to pursue a career in electronics, the natural history
of Missouri’s butterflies and moths (Lepidoptera) has been a
parallel avocation. For the past several years, my attention has
been directed toward the rare butterfly species in Missouri.
After investigating butterflies associated with wetlands, I
turned my attention to prairie species in 2004. I wanted to
collect as much baseline information on prairie butterflies as
I could within a week’s vacation time on prairies from which
I had permission to collect.
In 2005 biologists with the Missouri Department
of Conservation suggested that I visit some of the more
pristine prairies of the state. I followed their advice and
studied butterflies on nine prairies, again during a week,
including the Missouri Prairie Foundation’s Golden Prairie
in Barton County. By studying the rarity of Missouri’s prairie
butterflies, I hope to contribute information to aid in their
conservation.
Prairie Management and Butterfly Conservation
Studying one group of animals can yield useful information
about the effects of prairie management on prairie fauna.
Butterflies are handy indicators of a prairie’s ecological
health because they are diurnal and conspicuous, and thus
relatively easy to find. In addition, they can be identified by
knowledgeable amateurs as well as professionals with relative
ease, which makes them an ideal study group.
Management regimes for Missouri’s remaining prairies—
both public and private—are usually designed to benefit plant
diversity, which is essential for the survival of the animals that
depend on prairies for habitat. Although a prairie may have
good plant diversity, it does not always follow that the animals
will thrive. Some experts believe that current management
practices, such as prescribed fire, have been causing the decline
of prairie butterflies for many years (Schlicht & Orwig, 1998).
The dean of Missouri Lepidoptera, Richard Heitzman, notes,
however, that prairie butterfly populations are usually low
but explode every five years or so (pers. comm.). As of yet, no
long-term research has been conducted on prairie butterflies
in Missouri that would help answer questions about effects of
prairie management on them.
MDC Photo
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betsy betros
Prairie Butterfly Habitats and Life Cycles
Each species of butterfly has different needs. Different species
do not occupy the same ecological niche even though they may
occupy the same geographical range. Some butterflies are true
prairie obligates while others can survive in the woody component of a prairie or live on prairies, savannas and glades. Others
do well almost everywhere including fallow fields and urban
gardens. The specialists are at risk if their resources dwindle but
can persist on small remnants for a long time if the right conditions are maintained. In the larval stage, some species require
a particular species or genus of host plant (specialists); others
feed on members of one plant family (oligophages), while some
are cosmopolitan in their feeding requirements (generalists)
(Summerville, 2004). The host plant must be in good health
or the life of the larva is in jeopardy. The adult prairie butterfly
must have a source of nectar for its survival, and not all nectar
sources may be of equal value for the survival and fecundity of
the adult (Ross, 2003). Butterflies also need the right habitat so
they can hide from predators and shelter themselves from the
elements.
Although we think of butterflies as very mobile creatures,
this is not always the case. Most adult butterflies live only
for two or three weeks, depending on the species and season.
During most of their lives, butterflies are grounded while in
the egg, larval and pupal stages. Because some species complete one generation a year while others complete two or three
generations, this immobile period occurs at different times for
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A Golden Byssus butterfly gathers nectar from a black-eyed Susan
flower head.
different species. Therefore, as far as butterfly conservation is
concerned, altering haying and prescribed burning on a given
prairie tract could minimize the impact that such management
techniques could have on butterfly species at grounded periods
of their life cycle. In addition, burns that are patchier and carried out at different seasons from one year to another could
help create refugia within a prairie for butterflies and other
invertebrates.
A female may lay hundreds of eggs. In many cases, no matter what the species, almost all immature butterflies will not
survive. Natural variations in environmental factors (e.g., fewer
or more predators, precipitation, amount of host or nectar
plant material) can account for more or fewer eggs reaching
adulthood, thus causing a population to temporarily explode or
decline.
Levels of Butterfly Rarity
I consider a butterfly to be rare if it meets any one of the following three conditions. First, if a species is listed as globally or
federally endangered, it must be protected. Fortunately, none
of Missouri’s Lepidoptera is on the global or federal endangered
species lists.
Second, a species may be state listed as a species of conservation concern. One of the reasons that a species may be listed
by the state is that its normal range barely enters Missouri but
it may be common elsewhere. All species are reviewed by the
Missouri Department of Conservation, and a list is published
annually (MDC, 2007). The definitions for state and global
rankings for species of conservation concern are as follows:
S1 = Critically Imperiled: Critically imperiled in the nation or state
because of extreme rarity or because of some factor(s) making
it especially vulnerable to extirpation from the state. Typically,
5 or fewer occurrences or very few remaining individuals
(<1,000).
S2 = Imperiled: Imperiled in the nation or state because of rarity
or because of some factor(s) making it very vulnerable to extirpation from the nation or state (1,000 to 3,000 individuals).
S3 = Vulnerable: Vulnerable in the nation or state either because
the species is rare and uncommon, or found only in a restricted
range (even if abundant at some locations), or because of other
factors making it vulnerable to extirpation. Typically 21 to 100
occurrences or between 3,000 and 10,000 individuals.
G1 = Critically Imperiled: Critically imperiled globally because of
extreme rarity or because of some factor(s) making it especially
vulnerable to extinction. Typically 5 or fewer occurrences or
very few remaining individuals (<1,999).
G2 = Imperiled: Imperiled globally because of rarity or because
of some factor(s) making it very vulnerable to extinction or
elimination. Typically 6 to 20 occurrences or few remaining
individuals (1,000 to 3,000).
G3 = Vulnerable: Vulnerable globally either because very rare and
local throughout its range, found only in a restricted range
(even if abundant at some locations), or because of other
factors making it vulnerable to extinction or elimination.
Typically 21 to 100 occurrences or between 3,000 and 10,000
individuals.
G4 = Apparently Secure: Uncommon but not rare (although it
may be rare in parts of its range, particularly on the periphery),
and usually widespread. Apparently not vulnerable in most of
its range, but possibly cause for long-term concern. Typically
more than 100 occurrences and more than 10,000 individuals.
The final condition for being considered rare (although not
necessarily listed as so by the state) is that a species is not found
regularly.
In 2005, there were 10 species of butterflies and moths
listed as species of conservation concern in Missouri. Two of
these—the Ottoe skipper (Hesperia ottoe) and the Regal fritillary (Speyeria idalia occidentalis)—are prairie obligate butterflies. These two, and five other Missouri prairie butterflies
that are deemed rare according to the above conditions are
listed on the following two pages. Table 1 on page 26 tabulates
my observations of the presence of four of Missouri’s seven rare
prairie butterflies on the nine prairies I visited in 2005, based
on my observations between June 13 and June 18. I did not
see the Ottoe, Green or Dotted skippers. The table provides
voucher information as well.
(article continues on page 27)
Long-Term Butterfly Study
Observing and collecting prairie butterflies for a few hours or even a
few days, as I did in 2004 and 2005, provides a snapshot of species
diversity, but it does not provide definitive information of the overall
species richness of a location. Ideally, observations should be made
frequently in the same areas over a period of several years. A project
of this magnitude could be costly but much of the work could be
done by volunteers who live near the prairies being surveyed.
Voucher specimens of some species are needed for definitive
identification. A collecting permit is required from the owner of
the property, and an additional permit is required by the Missouri
Department of Conservation if species of conservation concern are to
be vouchered on public land. Also, special restrictions on collecting
may apply. Modern cameras can provide excellent pictures of
butterflies but seldom show all of the wing surfaces, both dorsal and
ventral, which may be needed to identify some species. Photos can
be helpful but they are not equivalent to voucher specimens.
Missouri Prairie Foundation members who are interested in
learning to identify prairie butterflies and helping with a long-term
study of their populations should contact me at [email protected].
org. I would be delighted to help coordinate such a study.
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♀
♂
The Ottoe skipper (Hesperia ottoe) is
found on mixed grass to tallgrass prairie on the
Great Plains and dry fields and prairies near the
Great Lakes (Scott, 1992). It has a state rank of
S1 and a global rank of G3/G4. There are 12
Missouri records from seven locations. It was not
found in 2004 and 2005 from these locations but
it is likely to occur elsewhere in Missouri.
The Green skipper or Black-dust
skipper (Hesperia viridis) is a prairie species
and can also be found in pine or oak woodland
(Scott, 1992). It has no Missouri state rank and
has been recorded once in St. Clair County,
Missouri. The date of capture is not known. The
normal range of this species comes closest to
Missouri in south-central Kansas. If a population
exists in Missouri, it would be isolated from its
normal range.
The Dotted skipper (Hesperia attalus
attalus) is found in oak/pine barrens, woodland
meadows and prairies (Scott, 1992). It has no
ranking in Missouri. The range of this subspecies
is from the southwestern corner of Missouri west
through south-central Kansas and south through
central Oklahoma into northeastern Texas. There
are two Missouri records for the Dotted skipper
from St. Clair County. One is listed as being collected in the 1960s.
Male/female photos of butterflies by Phillip Koenig
The Cross-line skipper (Polites origenes
origenes) is found in meadows, open woods
and prairies (Scott, 992). It has no ranking in
Missouri. There are records from 64 locations in
Missouri with two more locations added in 2004
and four more in 2005. I found it on six of the
nine prairies that I visited in 2005 and also at
Roaring River State Park, Barry County.
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♀
♂
The Arogos skipper (Atrytone arogos iowa)
is found in grassy places and prairies (Scott,
1992). It has no ranking in Missouri. There are
five historic locations in Missouri. It was not
found in 2004 but was one of the most common
species on the prairies I sampled in 2005 with
four new locations added. I found it on seven of
the nine prairies that I visited in 2005. Its numbers may fluctuate greatly.
The Golden byssus (Problema byssus
kumskaka) is found on damp prairies and other
grassy areas (Scott, 1992). It is not ranked and is
widely distributed in Missouri. It has 32 historic
locations in Missouri with three new locations I found in 2004 and two added in 2005.
MDC Photo
The Regal fritillary (Speyeria
idalia occidentalis) is ranked S3 in the
state and G3 globally. There are 85
historic locations for this species in the
state with six new locations added in
2004 and three added in 2005. Actual
populations are much fewer because
individuals stray, perhaps looking
for new habitat. It has been found
in unlikely places such as the City of
Florissant in St. Louis County. It is
normally found in wet meadows and
moist prairie (Scott, 1992). Although
many colonies have disappeared in
other states, it was found in good numbers on all nine of the prairies that I visited in 2005. It was not vouchered at
Wah’Kon-Tah in 2005 and has never
been vouchered at Shelton L. Cook
Memorial Meadow.
Gathering nectar from butterfly weed alongside the regal fritillary (at right) are gray copper butterflies.
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Phillip Koening
Wah’Kon-Tah Prairie in St. Clair County is one of the prairies surveyed by the author in June 2005.
Table 1. This table indicates the
presence of four of Missouri’s
seven rare prairie butterflies
on the nine prairies visited by
the author in 2005, based on his
observations between June 13
and June 18. He did not see the
Ottoe, Green or Dotted skippers.
WP
TP
Cross-line skipper
L
X
Arogos skipper
L
X
LO
PSP
X
C
Golden byssus
Regal fritillary
OP
L
SC
GP
C
L
X
L
X
O
DC
X
X
L
O
X
L
X
L
L
WPWah’Kon-Tah Prairie, St. Clair County, owned by The Nature Conservancy (TNC) and
managed by the Missouri Department of Conservation (MDC)
TP
Taberville Prairie, St. Clair County, MDC owned and managed
LO
Little Osage Prairie Conservation Area, Vernon County, TNC owned, MDC managed
OP
Osage Prairie Conservation Area, Vernon County, MDC owned and managed
PSP
Prairie State Park, Barton County, owned and managed by the Department of Natural Resources
SC
Shelton L. Cook Memorial Meadow, Barton County, TNC owned and managed
GP
Golden Prairie, Barton County, owned and managed by the Missouri Prairie Foundation (MPF)
DC
Dorris Creek Prairie Conservation Area, Barton County, MDC owned and managed
26
DG
DG
Diamond Grove Prairie Conservation Area, Newton County, MDC owned and managed
C
L
X
First vouchered county and location record
First vouchered location record
Vouchered
O
Observed
X
Phillip Koening
Arogos skippers gather nectar from a pale purple coneflower.
Most of the butterflies I observed congregated where
nectar sources were abundant. In many cases, prairie flowers
were blooming most profusely between the area’s parking
lot and the nearby signage. Butterfly weed and thistle species
(Cirsium spp.) are the favorites but are not very common. Pale
purple coneflower was busy but no longer at its peak, so many
butterflies preferred wild bergamot. Black-eyed Susans were
abundant in many locations but seldom used.
The Arogos skipper, normally rare and not found in 2004,
was common on seven of the nine prairies visited in 2005. This
indicates that the species is well distributed, is normally found
at low numbers and undergoes an occasional population explosion. Also, various forms of prairie management employed by
MDC, DNR and TNC do not seem to have affected this species because the population explosion occurred on one or more
of their prairies. It was not found on MPF’s Golden Prairie, the
only MPF prairie I visited.
The cause of the population explosion is not understood.
Although the population can increase rapidly, we do not know
if it is declining over a number of years. We do not know if the
populations of other species of skippers cycle in a similar manner. The question remains unanswered, at least in Missouri.
There is not enough information to detect a change in population density over the years. The best defense against species
loss is by maintaining prairies at varying times of the year with
a mix of burning, grazing, mowing and leaving some sections
undisturbed. This may not always be practical from a management point of view, but it is a good goal.
Literature Cited
Missouri Department of Conservation. 2007. Missouri Species
and Communities of Conservation Concern. Missouri
Department of Conservation, Jefferson City.
Ross, Gary N. 2003. What’s for Dinner? A New Look at the
Role of Phytochemicals in Butterfly Diets. Lep. News
45(3):83-89. (Autumn 2003).
Schlicht, Dennis W. & Timothy T. Orwig. 1998. The Status of
Iowa’s Lepidoptera. Jour. Iowa Acad. Sci. 105(2):82-88.
Scott, James A. 1992. The Butterflies of North America. A Natural History and Field Guide. Stanford University
Press, Palo Alto.
Summerville, Keith S. 2004. Functional Groups and Species
Replacement: Testing for the Effects of Habitat Loss on
Moth Communities. J. Lepid. Soc. 58(2):114-117.
Other Lepidoptera References:
Heitzman, J. Richard and Joan E. Heitzman. 1996. Butterflies
and Moths of Missouri. Missouri Department of
Conservation, Jefferson City.
Heitzman’s Lepidoptera of Missouri Database (unpublished).
Contact the author for information.
Opler, P.A. 1992. A field guide to eastern butterflies.
Houghton Mifflin Co., New York. 369 pp.
Ross, Gary Noel. 2001. Butterflies of the Wah’Kon-Tah
Prairie. Holarctic Lepidoptera Vol.8, No. 1-2.
Shapiro, A.M. 1979. Erynnis baptisiae (Hesperiidae) on crown
vetch (Leguminosae). J. Lepid. Soc. 33:258.
Missouri Prairie Foundation member
Phillip E. Koenig is a life-long amateur lepidopterist
who maintains a collection of about 5,000 butterflies of
North and South America. He holds or has held collecting
permits from the Missouri Prairie Foundation, the Missouri
Department of Conservation, the Missouri Department
of Natural Resources, The Nature Conservancy, the U.S.
Fish and Wildlife Service and the country of Ecuador.
He created a computer program that assists in the
identification of skipper butterflies of Kansas and
Missouri. His current interest is in locating colonies of
butterfly species of conservation concern. He has
recently completed an electronic database of Richard
Heitzman’s hand-written notes on butterfly and moth
historical locations in Missouri.
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