Insect Frontiers December 2009 Volume 1 Nomber 2

Transcription

December 2009 Volume 1 Nomber 2
Insect Frontiers
BPH (brown planthopper)-resistance test of the Bph14transgenic and susceptible wild-type (WT) rice. RI35, resistant parental rice; Kasalath, susceptible WT rice; Ra1–Ra10,
Bph14-transgenic T2 lines. (From PNAS 2009 106:2216322168; Abstract No. 9 in this issue. OA article).
Insect Frontiers, December 2009 Volume 1 Number 2
Insect Behaviour
1. A polyandrous female moth discriminates against previous mates to gain genetic diversity
Animal Behaviour Volume 78, Issue 6, December 2009, Pages 1309-1315
2.
Queen replacement in the monogynous ant Aphaenogaster senilis: supernumerary queens
as life insurance
3. Sexual selection for genetic quality: disentangling the roles of male and female behaviour
4. Policing and dominance behaviour in the parthenogenetic ant Platythyrea punctata
5. Unexpected absence of behavioural differences between female damselfly colour morphs
6. Homosexual interactions in bed bugs: alarm pheromones as male recognition signals
7. Preimaginal and Adult Experience Modulates the Thermal Response Behavior of Ants
Current Biology, Volume 19, Issue 22, 1897-1902, 12 November 2009
8. Preferential Ethanol Consumption in Drosophila Models Features of Addiction
Current Biology, Volume 19, Issue 24, 2126-2132, 10 December 2009
Insect Biocontrol
9.
Identification and characterization of Bph14, a gene conferring resistance to brown
planthopper in rice
PNAS December 29, 2009 vol. 106 no. 52 22163-22168
Insect Cell Biology
10. A Wolbachia Symbiont in Aedes aegypti Limits Infection with Dengue, Chikungunya, and
Plasmodium
Cell, Volume 139, Issue 7, 1268-1278, 24 December 2009
11. Increased Cell Bond Tension Governs Cell Sorting at the Drosophila Anteroposterior
Compartment Boundary
Current Biology, Volume 19, Issue 22, 1950-1955, 29 October 2009
Insect Cellular Metabolisom
12. Schlank, a member of the ceramide synthase family controls growth and body fat in
Drosophila
The EMBO Journal (2009) 28, 3706 - 3716
Insect Chemoecology
13. Molecular Characterization and Expression Pattern of Two General Odorant Binding Proteins
from the Diamondback Moth, Plutella xylostella
Journal of Chemical Ecology Volume 35, Number 10 / October, 2009 1188-1196
14. Whiteflies interfere with indirect plant defense against spider mites in Lima bean
Insect Clock
15. The CRYPTOCHROME Photoreceptor Gates PDF Neuropeptide Signaling to Set Circadian
Network Hierarchy in Drosophila
Insect Development
16. Function of Drosophila mob2 in photoreceptor morphogenesis
Cell and Tissue Research Volume 338, Number 3 / December, 2009 377-389
17. Visualization of Individual Scr mRNAs during Drosophila Embryogenesis Yields Evidence for
Transcriptional Bursting
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18. Hedgehog, but not Odd skipped, induces segmental grooves in the Drosophila epidermis
Development 136, 3875-3880 December 1, 2009.
19. Sanpodo: a context-dependent activator and inhibitor of Notch signaling during asymmetric
divisions
20. The cadherin Fat2 is required for planar cell polarity in the Drosophila ovary
21. Effete-mediated degradation of Cyclin A is essential for the maintenance of germline stem
cells in Drosophila
22. Drosophila laminins act as key regulators of basement membrane assembly and
morphogenesis
23. Control in time and space: Tramtrack69 cooperates with Notch and Ecdysone to repress
ectopic fate and shape changes during Drosophila egg chamber maturation
24. Vasa promotes Drosophila germline stem cell differentiation by activating mei-P26
translation by directly interacting with a (U)-rich motif in its 3′ UTR
Genes & Dev. 2009. 23: 2742-2752
Insect Ecology
25. Phase-dependent outbreak dynamics of geometrid moth linked to host plant phenology
Proc. R. Soc. B 7 December 2009 vol. 276 no. 1676 4119-4128
Insect Evolution
26. Repeated Co-options of Exoskeleton Formation during Wing-to-Elytron Evolution in Beetles
27. EFFECTS OF PARTHENOGENESIS AND GEOGRAPHIC ISOLATION ON FEMALE SEXUAL TRAITS
IN A PARASITOID WASP
Evolution Volume 63 Issue 12, Pages 3085 – 3096 Published Online: 30 Jul 2009
28. THE TEMPO AND MODE OF EVOLUTION OF TRANSPOSABLE ELEMENTS AS REVEALED BY
MOLECULAR PHYLOGENIES RECONSTRUCTED FROM MOSQUITO GENOMES
29. EVOLUTION OF IDENTITY SIGNALS: FREQUENCY-DEPENDENT BENEFITS OF DISTINCTIVE
PHENOTYPES USED FOR INDIVIDUAL RECOGNITION
Evolution Volume 63 Issue 12, Pages 3106 – 3113 Published Online: 9 Sep 2009
30. Bacterial gut symbionts are tightly linked with the evolution of herbivory in ants
31. Ejaculate components delay reproductive senescence while elevating female reproductive
rate in an insect
Insect Genetics
32. Little Effect of the tan Locus on Pigmentation in Female Hybrids between Drosophila
santomea and D. melanogaster
33. Evolution of the tan Locus Contributed to Pigment Loss in Drosophila santomea: A Response
to Matute et al.
34. X-Linked Variation in Immune Response in Drosophila melanogaster
Genetics, Vol. 183, 1477-1491, December 2009
35. Altered Heterochromatin Binding by a Hybrid Sterility Protein in Drosophila Sibling Species
Science 11 December 2009 Vol. 326. no. 5959, pp. 1538 – 1541
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Insect Hearing
36. The cost of assuming the life history of a host: acoustic startle in the parasitoid fly Ormia
ochracea
Journal of Experimental Biology 212, 4056-4064 (2009)
37. Moths are not silent, but whisper ultrasonic courtship songs
38. The next step in cicada audition: measuring pico-mechanics in the cicada's ear
39. Acoustical mimicry in a predatory social parasite of ants
40. Evaluation of amplitude in male song: female waxmoths respond to fortissimo notes
Insect Learning
41. Interspecific and intersexual learning rate differences in four butterfly species
42. Thermal learning in the honeybee, Apis mellifera
43. Structural and proteomic analyses reveal regional brain differences during honeybee aging
44. Olfactory conditioning of the sting extension reflex in honeybees: Memory dependence on
trial number, interstimulus interval, intertrial interval, and protein synthesis
Learn. Mem. 2009. 16: 761-765
45. Social learning about egg-laying substrates in fruitflies
Insect Metamorphosis
46. MicroRNA-dependent metamorphosis in hemimetabolan insects
47. The Insect Neuropeptide PTTH Activates Receptor Tyrosine Kinase Torso to Initiate
Metamorphosis
Science 4 December 2009: Vol. 326. no. 5958, pp. 1403 – 1405
Insect Molecular Biology
48. Functional involvement of Tudor and dPRMT5 in the piRNA processing pathway in
Drosophila germlines
The EMBO Journal (2009) 28, 3820 - 3831
49. Pretaporter, a Drosophila protein serving as a ligand for Draper in the phagocytosis of
apoptotic cells
The EMBO Journal (2009) 28, 3868 – 3878
50. Spatial distribution of opsin-encoding mRNAs in the tiered larval retinas of the sunburst
diving beetle Thermonectus marmoratus (Coleoptera: Dytiscidae)
51. The Drosophila DHR96 nuclear receptor binds cholesterol and regulates cholesterol
homeostasis
Genes & Dev. 2009. 23: 2711-2716
52. A novel histone fold domain-containing protein that replaces TAF6 in Drosophila SAGA is
required for SAGA-dependent gene expression
Genes & Dev. 2009. 23: 2818-2823
Insect Neuroethology
53. Local and global motion preferences in descending neurons of the fly
Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology Volume 195,
Number 12 / December, 2009 1107-1120
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54. A descending contralateral directionally selective movement detector in the praying mantis
Tenodera aridifolia
Number 12 / December, 2009 1131-1139
Insect Neuroscience
55. Ems and Nkx6 are central regulators in dorsoventral patterning of the Drosophila brain
56. The target of rapamycin complex 2 controls dendritic tiling of Drosophila sensory neurons
through the Tricornered kinase signalling pathway
The EMBO Journal (2009) 28, 3879 – 3892
57. Imaging neural activity in worms, flies and mice with improved GCaMP calcium indicators
Nature Methods 6, 875 - 881 (2009) Published online: 8 November 2009
58. Leucine-rich repeat transmembrane proteins instruct discrete dendrite targeting in an
olfactory map
Nature Neuroscience 12, 1542 - 1550 (2009) Published online: 15 November 2009
59. Frequency Transitions in Odor-Evoked Neural Oscillations
Neuron, Volume 64, Issue 5, 692-706, 10 December 2009
60. Glycogen synthase kinase-3/Shaggy mediates ethanol-induced excitotoxic cell death of
Drosophila olfactory neurons
61. Peripheral modulation of worker bee responses to queen mandibular pheromone
Insect Nutrition
62. Amino-acid imbalance explains extension of lifespan by dietary restriction in Drosophila
Nature 462, 1061-1064 (24 December 2009)
Insect Pharmacology
63. Transduction mechanism(s) of Na-saccharin in the blowfly Protophormia terraenovae:
evidence for potassium and calcium conductance involvement
Number 12 / December, 2009 1141-1151
Insect Photoreception
64. Specialized ommatidia of the polarization-sensitive dorsal rim area in the eye of monarch
butterflies have non-functional reflecting tapeta
Insect Physiology
65. Isoform- and cell-specific function of tyrosine decarboxylase in the Drosophila Malpighian
tubule
Insect Sex Determination
66. The origin of a selfish B chromosome triggering paternal sex ratio in the parasitoid wasp
Trichogramma kaykai
Insect Society
67. Brood pheromone suppresses physiology of extreme longevity in honeybees (Apis mellifera)
68. Flexible task allocation and the organization of work in ants
69. Polymorphic social organization in an ant
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Insect Vision
70. Visual detection of diminutive floral guides in the bumblebee Bombus terrestris and in the
honeybee Apis mellifera
Number 12 / December, 2009 1121-1130
Insect Review
71. Are Bigger Brains Better?
Current Biology, Volume 19, Issue 21, R995-R1008, 17 November 2009
72. A Review of Ant Cuticular Hydrocarbons
73. Courtship learning in Drosophila melanogaster: Diverse plasticity of a reproductive behavior
Learn. Mem. 2009. 16: 743-750
74. Circadian rhythms and the evolution of photoperiodic timing in insects
Physiological Entomology Volume 34 Issue 4, Pages 301 – 308 Published Online: 19 Nov 2009
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Insect Behaviour
1. A polyandrous female moth discriminates against previous mates to gain
genetic diversity
Jin Xua and Qiao Wanga,
a
Institute of Natural Resources, Massey University, New Zealand
Polyandry is common in many animal species. The hypotheses proposed to explain the
evolution of polyandry generally fall into two categories: to gain material benefits and to
obtain genetic benefits. Here we report our findings on a polyandrous moth, Ephestia
kuehniella (Lepidoptera: Pyralidae). The present study does not support the hypothesis
that females gain material benefits from multiple copulations in terms of sperm
replenishment, fecundity and longevity, because females that copulated once and
females that copulated more than once with the same or different males had similar
fertility, fecundity and longevity. Females used three strategies to gain possible genetic
benefits: discriminating against previous mates probably via chemical cues, giving 60%
chance of paternity to second males, and adjusting their oviposition patterns depending
on whether they encountered new or previous mates after the first copulation. For the
third strategy, females that encountered new mates after the first copulation saved eggs
until the next day to facilitate fertilization of their eggs with the sperm of their new mates.
Our findings do not support the hypothesis that polyandry increases offspring viability,
because polyandry did not affect egg hatching success, offspring survival or weight.
Ephestia kuehniella showed limited ability to disperse, and females laid all their eggs
locally, mostly within 2 days, suggesting that offspring live together and that sib
copulations are common in this species. Therefore, polyandry is probably a mechanism
for reducing sib competition and inbreeding costs in offspring.
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6W9W-4XHT4FV3&_user=10&_coverDate=12%2F31%2F2009&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_acct=C000050221
&_version=1&_urlVersion=0&_userid=10&md5=66cbb05a9c470d5aec2758f4759b03ea
2. Queen replacement in the monogynous ant Aphaenogaster senilis:
supernumerary queens as life insurance
Blandine Chérona, Claudie Doumsa, b, Pierre Fédéricia and Thibaud Monnina
a
Laboratoire Écologie & Évolution CNRS UMR 7625, Université Pierre et Marie Curie - Paris 6, France
b
École Pratique des Hautes Études, Paris, France
In social groups, the replacement of the breeder may generate conflicts. In eusocial
hymenoptera these can occur between queens, between queens and workers, or between
workers. We investigated queen replacement in the Mediterranean ant Aphaenogaster
senilis, a monogynous (one queen per colony) species that reproduces exclusively by
colony fission. We first investigated the potential for worker nepotism by analysing the
sociogenetic structure in 31 colonies using microsatellite markers. No polyandry was
detected, which eliminates the possibility of worker nepotism. Second, 30 colonies were
experimentally orphaned to analyse the production of gynes (unmated, hopeful queens).
Workers reared on average two gynes from the previous queen's diploid brood, with the
firstborn gyne emerging on average 17 days before the other, supernumerary, gyne(s).
The production of only a few gynes severely limits the potential for gyne selection based
on quality criteria. Furthermore, such selection would be biased by the asynchrony of
gyne emergence which precludes comparing gynes of the same age and maturity.
Behavioural observations showed that gynes interacted aggressively and that the
firstborn gyne was always dominant. She usually survived while supernumerary gynes
seldom did, even though they did not differ in weight. Workers also attacked gynes, and
preferentially targeted supernumerary gynes. We propose that supernumerary gynes are
produced as insurance in the eventuality of the death of the firstborn gyne, and that the
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delay between the emergence of gynes minimizes the risk that aggressive interactions
between gynes will lead to all gynes being killed.
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6W9W-4XDFDNJ1&_user=10&_coverDate=12%2F31%2F2009&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_acct=C000050221
&_version=1&_urlVersion=0&_userid=10&md5=c02ec861e4282f17e7c91887fffee6a4
3. Sexual selection for genetic quality: disentangling the roles of male and
female behaviour
Nina Pekkala aMikael Puurtinena and Janne S. Kotiahoa
a
Centre of Excellence in Evolutionary Research, Department of Biological and Environmental Science,
University of Jyväskylä, Finland
According to the good genes model of sexual selection, females choose males of good
heritable genetic quality to obtain offspring with high fitness. However, better mating
success of high-quality males can also be brought about by direct interference
competition between males, or simply through elevated activity of high-quality males.
We examined the roles of different processes leading to sexual selection for genetic
quality in Drosophila montana. We manipulated genetic quality of male flies by inducing
mutations with ionizing radiation. We then recorded the effects of inherited heterozygous
mutations on several aspects of mating behaviour of males and females in two
experiments. We found that mutations reduced the probability of courtship and extended
the latency to courtship of the males, suggesting male activity plays a role in selection
for genetic quality. However, the effects of mutations on mating success and mating
behaviour of the flies were in general weak. No evidence for female mate choice or
interference competition between males acting against heritable mutations was found.
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6W9W-4XFXSWD1&_user=10&_coverDate=12%2F31%2F2009&_rdoc=12&_fmt=high&_orig=browse&_srch=docinfo(%23toc%236693%232009%23999219993%231571357%23FLA%23display%23Volume)&_cdi=6693&_sort=d&_docanchor=&
view=c&_ct=36&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=7310425580e7abc351dd95f61377b259
4. Policing and dominance behaviour in the parthenogenetic ant Platythyrea
punctata
Elisabeth Brunner1, a, Katrin Kellner, 1, a, and Jürgen Heinzea
a
Biologie I, University of Regensburg, Germany
In the parthenogenetic ant Platythyrea punctata policing behaviour is not expected on
relatedness grounds as workers are normally clonemates and thus equally related to all
offspring in the colony. Nevertheless, colonies usually contain only a single reproductive
and other workers that begin to lay eggs are attacked by their nestmates (‘policing’). We
found that those individuals that most actively engaged in policing later themselves had
activated ovaries when the old reproductive was removed from the colonies. This
suggests that police workers, through attacking and eliminating others, increase their
own chances of becoming reproductive themselves. Because regular parthenogenesis
leads to a clonal colony structure, individuals are not expected to invest energy in
dominance and policing. On the assumption that physical dominance reflects an
individual's reproductive potential, aggression among workers might ensure that the
most fecund individual becomes the next reproductive, which would benefit the colony as
a whole. Furthermore, aggression among nestmates may be maintained in this species
despite predominant clonality, because infrequent sex, recombination or the adoption of
alien workers may introduce genetic heterogeneity into the colony.
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6W9W-4XFF2RR1&_user=10&_coverDate=12%2F31%2F2009&_rdoc=21&_fmt=high&_orig=browse&_srch=docinfo(%23toc%236693%232009%23999219993%231571357%23FLA%23display%23Volume)&_cdi=6693&_sort=d&_docanchor=&
view=c&_ct=36&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=20f7005b4a6f76c8827f10e3a779d240
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5. Unexpected absence of behavioural differences between female damselfly
colour morphs
Arne Iserbyt a, and Hans Van Gossuma
a
Evolutionary Ecology Group, University of Antwerp, Belgium
Males are often selected for higher mating rates than females. As a consequence of this
sexual conflict, unreceptive females may suffer fitness costs from excessive male sexual
harassment. In a variety of vertebrate and invertebrate species, multiple female morphs
coexist in natural populations which have been observed to differ in body colour, in
behaviour and also in the amount of male harassment received. However, the degree of
harassment on a female morph may depend on the frequency and density of males and
female morphs in the population. We quantified harassment rate and subsequent refusal
behaviour of males and female morphs of the polymorphic damselfly Nehalennia irene.
Unexpectedly and contrary to previous work, female morphs received similar amounts of
male harassment and showed mostly the same behaviour. We discuss why differences in
morph behaviours may be lacking and how this compares to contemporary explanations
for the maintenance and evolution of female-limited polymorphisms.
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6W9W-4XJ13T62&_user=10&_coverDate=12%2F31%2F2009&_rdoc=26&_fmt=high&_orig=browse&_srch=docinfo(%23toc%236693%232009%23999219993%231571357%23FLA%23display%23Volume)&_cdi=6693&_sort=d&_docanchor=&
view=c&_ct=36&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=e1ab49ca435b43f054f00bc38ec339fc
6. Homosexual interactions in bed bugs: alarm pheromones as male
recognition signals
Camilla Ryne a,
a
Department of Ecology, Lund University, Sweden
Homosexual mounting is a common behaviour in bed bugs as male sexual interest is
directed towards any newly fed individual. The only mode of copulation in the common
bed bug, Cimex lectularius, is by traumatic insemination, where the male pierces the
female abdomen with his needle-like penis. Homosexual mating would result in
abdominal injuries in mounted males, as males lack the female counteradaptive
spermalege structure. I here show that bed bug alarm pheromones, previously
hypothesized to be a predator chemical defence, can be used by newly fed males to
signal their sex and reduce the risk of homosexual mating. Mechanical blocking of the
male pheromone glands significantly increased homosexual mounting duration compared
to control males, while applying male extracts containing mainly alarm pheromone onto
male–female mating pairs completely interrupted or shortened mating duration and
reduced sperm transfer. Males confined with other males received piercing scars,
demonstrating that homosexual mating occurs. The focal males in the all-male
confinement experiment had reduced longevity compared to singly held males, but why
this reduction in longevity occurred is not clear. Mounted males thus benefit from being
able to discharge alarm pheromones, while mounting males consider the alarm signal a
major sex identification cue, suggesting that male bed bugs use alarm pheromone
communication to avoid homosexual harassment and mounting.
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6W9W-4XHT4FV4&_user=10&_coverDate=12%2F31%2F2009&_rdoc=27&_fmt=high&_orig=browse&_srch=docinfo(%23toc%236693%232009%23999219993%231571357%23FLA%23display%23Volume)&_cdi=6693&_sort=d&_docanchor=&
view=c&_ct=36&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=d5c945ad04335678e01374833743116b
7. Preimaginal and Adult Experience Modulates the Thermal Response
Behavior of Ants
Anja Weidenmüller1,, Christina Mayr1, Christoph Johannes Kleineidam1 and Flavio Roces1
8
1
Behavioral Physiology and Sociobiology, Biozentrum, Am Hubland, Universität Würzburg, D-97074
Würzburg, Germany
Colonies of social insects display an amazing degree of flexibility in dealing with longterm and short-term perturbations in their environment. The key organizational element
of insect societies is division of labor. Recent literature suggests that interindividual
variability in response thresholds plays an important role in the emergence of division of
labor among workers (reviewed in [1,2]). Genetic variation can only partly explain the
variability among workers. Here we document the effects of both preimaginal and adult
thermal experience on the behavioral differentiation of Camponotus rufipes ant workers.
We show that preimaginal temperature (22°C or 32°C during pupal stage) affects
temperature-response thresholds and temperature preferences of adult brood-tending
workers. We further show that brood-carrying experience gathered as adult during
several repeated temperature increases modifies thermal behavior. Experienced workers
showed a faster transition from first sensing the temperature stimulus to responding with
brood translocation. Developmental plasticity of workers provides a colony with flexibility
in dealing with thermal variations and constitutes an important mechanism underlying
interindividual variability. Adult thermal experience further fine tunes the behavioral
response thresholds and reinforces behavioral differentiation among workers.
http://www.cell.com/current-biology/abstract/S0960-9822%2809%2901760-6
8. Preferential Ethanol Consumption in Drosophila Models Features of
Addiction
Anita V. Devineni1, and Ulrike Heberlein2,
1
Program in Neuroscience, University of California, San Francisco, San Francisco, CA 94143-2822, USA
2
Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143-2822, USA
Alcohol addiction is a common affliction with a strong genetic component [1]. Although
mammalian studies have provided significant insight into the molecular mechanisms
underlying ethanol consumption [2], other organisms such as Drosophila melanogaster
are better suited for unbiased, forward genetic approaches to identify novel genes.
Behavioral responses to ethanol, such as hyperactivity, sedation, and tolerance, are
conserved between flies and mammals [3,4], as are the underlying molecular pathways
[5,6,7,8,9]. However, few studies have investigated ethanol self-administration in flies
[10]. Here we characterize ethanol consumption and preference in Drosophila. Flies
prefer to consume ethanol-containing food over regular food, and this preference
increases over time. Flies are attracted to the smell of ethanol, which partially mediates
ethanol preference, but are averse to its taste. Preference for consuming ethanol is not
entirely explained by attraction to either its sensory or caloric properties. We
demonstrate that flies can exhibit features of alcohol addiction. First, flies self-administer
ethanol to pharmacologically relevant concentrations. Second, flies will overcome an
aversive stimulus in order to consume ethanol. Third, flies rapidly return to high levels of
ethanol consumption after a period of imposed abstinence. Thus, ethanol preference in
Drosophila provides a new model for studying aspects of addiction.
http://www.cell.com/current-biology/abstract/S0960-9822(09)01942-3
Insect Biocontrol
9. Identification and characterization of Bph14, a gene conferring resistance
to brown planthopper in rice
Bo Dua,1, Weilin Zhanga,1, Bingfang Liua, Jing Hua, Zhe Weia, Zhenying Shia, Ruifeng Hea, Lili Zhua,
Rongzhi Chena, Bin Hanb and Guangcun Hea,2 [email protected]
a
Key Laboratory of Ministry of Education for Plant Development Biology, College of Life Sciences,
Wuhan University, Wuhan 430072, China; and
9
b
National Center for Gene Research, Shanghai Institutes for Biological Sciences, Chinese Academy of
Sciences, Shanghai 200233, China
Planthoppers are highly destructive pests in crop production worldwide. Brown
planthopper (BPH) causes the most serious damage of the rice crop globally among all
rice pests. Growing resistant varieties is the most effective and environment-friendly
strategy for protecting the crop from BPH. More than 19 BPH-resistance genes have been
reported and used to various extents in rice breeding and production. In this study, we
cloned Bph14, a gene conferring resistance to BPH at seedling and maturity stages of the
rice plant, using a map-base cloning approach. We show that Bph14 encodes a coiled-coil,
nucleotide-binding, and leucine-rich repeat (CC-NB-LRR) protein. Sequence comparison
indicates that Bph14 carries a unique LRR domain that might function in recognition of
the BPH insect invasion and activating the defense response. Bph14 is predominantly
expressed in vascular bundles, the site of BPH feeding. Expression of Bph14 activates the
salicylic acid signaling pathway and induces callose deposition in phloem cells and trypsin
inhibitor production after planthopper infestation, thus reducing the feeding, growth rate,
and longevity of the BPH insects. Our work provides insights into the molecular
mechanisms of rice defense against insects and facilitates the development of resistant
varieties to control this devastating insect.
http://www.pnas.org/content/106/52/22163.abstract?etoc
Top
Insect Cell Biology
10.A Wolbachia Symbiont in Aedes aegypti Limits Infection with Dengue,
Chikungunya, and Plasmodium
Luciano A. Moreira1, 2, Iñaki Iturbe-Ormaetxe1, Jason A. Jeffery3, Guangjin Lu3, Alyssa T. Pyke4, Lauren
M. Hedges1, Bruno C. Rocha2, Sonja Hall-Mendelin5, Andrew Day5, Markus Riegler1, 6, Leon E.
Hugo3, Karyn N. Johnson1, Brian H. Kay3, Elizabeth A. McGraw1, Andrew F. van den Hurk4, 5, Peter A.
Ryan3 and Scott L. O'Neill1,
1
School of Biological Sciences, The University of Queensland, Brisbane QLD 4072, Australia
2
René Rachou Research Institute- FIOCRUZ, Belo Horizonte MG, Brazil
3
Queensland Institute of Medical Research, Post Office Royal Brisbane Hospital, Brisbane QLD 4029,
Australia
4
Virology, Queensland Health Forensic and Scientific Services, Coopers Plains QLD 4108, Australia
5
School of Chemical and Molecular Biosciences, The University of Queensland, Brisbane QLD 4072,
Australia
Wolbachia are maternally inherited intracellular bacterial symbionts that are estimated to
infect more than 60% of all insect species. While Wolbachia is commonly found in many
mosquitoes it is absent from the species that are considered to be of major importance
for the transmission of human pathogens. The successful introduction of a life-shortening
strain of Wolbachia into the dengue vector Aedes aegypti that halves adult lifespan has
recently been reported. Here we show that this same Wolbachia infection also directly
inhibits the ability of a range of pathogens to infect this mosquito species. The effect is
Wolbachia strain specific and relates to Wolbachia priming of the mosquito innate
immune system and potentially competition for limiting cellular resources required for
pathogen replication. We suggest that this Wolbachia-mediated pathogen interference
may work synergistically with the life-shortening strategy proposed previously to provide
a powerful approach for the control of insect transmitted diseases.
http://www.cell.com/abstract/S0092-8674%2809%2901500-1
11.Increased Cell Bond Tension Governs Cell Sorting at the Drosophila
Anteroposterior Compartment Boundary
10
Katharina P. Landsberg1, 3, Reza Farhadifar2, 3, Jonas Ranft2, 3, Daiki Umetsu1, 3, Thomas J.
Widmann1, Thomas Bittig2, Amani Said1, Frank Jülicher2, and Christian Dahmann1
1
Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden,
Germany
2
Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Strasse 38, 01187 Dresden,
Germany
Subdividing proliferating tissues into compartments is an evolutionarily conserved
strategy of animal development [1,2,3,4,5,6]. Signals across boundaries between
compartments can result in local expression of secreted proteins organizing growth and
patterning of tissues [1,2,3,4,5,6]. Sharp and straight interfaces between compartments
are crucial for stabilizing the position of such organizers and therefore for precise
implementation of body plans. Maintaining boundaries in proliferating tissues requires
mechanisms to counteract cell rearrangements caused by cell division; however, the
nature of such mechanisms remains unclear. Here we quantitatively analyzed cell
morphology and the response to the laser ablation of cell bonds in the vicinity of the
anteroposterior compartment boundary in developing Drosophila wings. We found that
mechanical tension is approximately 2.5-fold increased on cell bonds along this
compartment boundary as compared to the remaining tissue. Cell bond tension is
decreased in the presence of Y-27632 [7], an inhibitor of Rho-kinase whose main effector
is Myosin II [8]. Simulations using a vertex model [9] demonstrate that a 2.5-fold
increase in local cell bond tension suffices to guide the rearrangement of cells after cell
division to maintain compartment boundaries. Our results provide a physical mechanism
in which the local increase in Myosin II-dependent cell bond tension directs cell sorting at
compartment boundaries.
Current Biology, Volume 19, Issue 22, 1950-1955, 29 October 2009
http://www.cell.com/current-biology/abstract/S0960-9822%2809%2901840-5
Top
Insect Cellular Metabolisom
12.Schlank, a member of the ceramide synthase family controls growth and
body fat in Drosophila
Reinhard Bauer1, André Voelzmann1, Bernadette Breiden2, Ute Schepers2, Hany Farwanah2, Ines Hahn1,
Franka Eckardt1, Konrad Sandhoff2 and Michael Hoch1 [email protected]; [email protected]
LIMES-Institute, Program Unit Development, Genetics & Molecular Physiology, Laboratory for Molecular
Developmental Biology, University of Bonn, Bonn, Germany
LIMES-Institute, Program Unit Membrane Biology & Lipid Biochemistry, c/o Kekulé Institute of Organic
Chemistry and Biochemistry, University of Bonn, Bonn, Germany
Ceramide synthases are highly conserved transmembrane proteins involved in the
biosynthesis of sphingolipids, which are essential structural components of eukaryotic
membranes and can act as second messengers regulating tissue homeostasis. However,
the role of these enzymes in development is poorly understood due to the lack of animal
models. We identified schlank as a new Drosophila member of the ceramide synthase
family. We demonstrate that schlank is involved in the de novo synthesis of a broad
range of ceramides, the key metabolites of sphingolipid biosynthesis. Unexpectedly,
schlank mutants also show reduction of storage fat, which is deposited as triacylglyerols
in the fat body. We found that schlank can positively regulate fatty acid synthesis by
promoting the expression of sterol-responsive element-binding protein (SREBP) and
SREBP-target genes. It further prevents lipolysis by downregulating the expression of
triacylglycerol lipase. Our results identify schlank as a new regulator of the balance
between lipogenesis and lipolysis in Drosophila. Furthermore, our studies of schlank and
the mammalian Lass2 family member suggest a novel role for ceramide synthases in
regulating body fat metabolism.
The EMBO Journal (2009) 28, 3706 - 3716
http://www.nature.com/emboj/journal/v28/n23/abs/emboj2009305a.html
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Top
Insect Chemoecology
13.Molecular Characterization and Expression Pattern of Two General
Odorant Binding Proteins from the Diamondback Moth, Plutella xylostella
Zhi-Chun Zhang1, Man-Qun Wang1 , Yao-Bin Lu2 and Guoan Zhang1 [email protected]
1. College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
2. Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences,
Hangzhou, 310021, China
In the Lepidoptera, odorant signals are thought to be mediated by general odorant
binding proteins (GOBPs) in the sensillar lymph surrounding the olfactory receptors. We
describe the identification and characterization of two new cDNAs encoding GOBPs from
the antennae of the diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae),
a species for which no GOBPs have been identified to date. We focused our investigation
on this olfactory protein family by using reverse transcription–polymerase chain reaction
strategies. The deduced amino acid sequences of PxylGOBP1 and PxylGOBP2 revealed
open reading frames of 168 and 163 amino acids, respectively, with six cysteine residues
in conserved positions relative to other known GOBPs. The alignment of the mature
PxylGOBPs with other Lepidoptera GOBPs showed high sequence identity (70–80%) with
other full-length sequences from GenBank. Sequence identity between PxylGOBP1and
PxylGOBP2 was only 50%, suggesting that the two proteins belong to different classes of
lepidopteran GOBPs. The expression patterns of the two PxylGOBP genes, with respect to
tissue distribution and sex, were further investigated by reverse transcription-polymerase
chain reaction (RT-PCR) and real-time PCR. Although the two GOBP genes were
expressed only in the antennae of both sexes, reflecting the antennal specificity of GOBPs,
the transcription levels of these genes depended on the sex, the age, the mating status,
and the genes.
http://www.springerlink.com/content/f58804m54772272p/
14.Whiteflies interfere with indirect plant defense against spider mites in
Lima bean
Peng-Jun Zhanga, Si-Jun Zhenga, Joop J. A. van Loona, Wilhelm Bolandb, Anja Davidb, Roland Mumma
and Marcel Dickea,1 [email protected]
a
Laboratory of Entomology, Wageningen University, P.O. Box 8031, 6700 EH, Wageningen, The
Netherlands; and
b
Max-Planck-Institute for Chemical Ecology, Hans Knoll Strasse 8, D-07745 Jena, Germany
Plants under herbivore attack are able to initiate indirect defense by synthesizing and
releasing complex blends of volatiles that attract natural enemies of the herbivore.
However, little is known about how plants respond to infestation by multiple herbivores,
particularly if these belong to different feeding guilds. Here, we report the interference by
a phloem-feeding insect, the whitefly Bemisia tabaci, with indirect plant defenses induced
by spider mites (Tetranychus urticae) in Lima bean (Phaseolus lunatus) plants. Additional
whitefly infestation of spider-mite infested plants resulted in a reduced attraction of
predatory mites (Phytoseiulus persimilis) compared to attraction to plants infested by
spider mites only. This interference is shown to result from the reduction in (E)-βocimene emission from plants infested by both spider mites and whiteflies. When using
exogenous salicylic acid (SA) application to mimic B. tabaci infestation, we observed
similar results in behavioral and chemical analyses. Phytohormone and gene-expression
analyses revealed that B. tabaci infestation, as well as SA application, inhibited spider
mite-induced jasmonic acid (JA) production and reduced the expression of two JAregulated genes, one of which encodes for the P. lunatus enzyme β-ocimene synthase
that catalyzes the synthesis of (E)-β-ocimene. Remarkably, B. tabaci infestation
12
concurrently inhibited SA production induced by spider mites. We therefore conclude that
in dual-infested Lima bean plants the suppression of the JA signaling pathway by whitefly
feeding is not due to enhanced SA levels.
Top
Insect Clock
15.The CRYPTOCHROME Photoreceptor Gates PDF Neuropeptide Signaling to
Set Circadian Network Hierarchy in Drosophila
Luoying Zhang1, Bridget C. Lear1, Adam Seluzicki1 and Ravi Allada1,
1
Department of Neurobiology and Physiology, Northwestern University, Evanston, IL 60208, USA
Circadian clocks in the brain are organized as coupled oscillators that integrate seasonal
cues such as light and temperature to time daily behaviors. In Drosophila, the PIGMENT
DISPERSING FACTOR (PDF) neuropeptide-expressing morning (M) and non-PDF evening
(E) cells are coupled cell groups important for morning and evening behavior,
respectively. Depending on day length, either M cells (short days) or E cells (long days)
dictate both the morning and the evening phase, a phenomenon that we term network
hierarchy. To examine the role of PDF in light-dark conditions, we examined flies lacking
both the PDF receptor (PDFR) and the circadian photoreceptor CRYPTOCHROME (CRY).
We found that subsets of E cells exhibit molecular oscillations antiphase to those of wildtype flies, single cry mutants, or single Pdfr mutants, demonstrating a potent role for PDF
in light-mediated entrainment, specifically in the absence of CRY. Moreover, we find that
the evening behavioral phase is more strongly reset by PDF(+) M cells in the absence of
CRY. On the basis of our findings, we propose that CRY can gate PDF signaling to
determine behavioral phase and network hierarchy.
Top
Insect Development
16.Function of Drosophila mob2 in photoreceptor morphogenesis
Ling-Yu Liu1, Cheng-Han Lin1 and Seng-Sheen Fan1 [email protected]
1Department of Life Science, Tunghai University, No. 181, Sec. 3, Taichung-Kan Road, Taichung, 407,
Taiwan, Republic of China
The Drosophila photoreceptor is a highly polarized cell; a mature photoreceptor cell in
Drosophila contains a photosensitive structure (the rhabdomere) and a supporting
membrane (stalk) at its apical membrane. In a screen to isolate genes involved in
determining stalk and rhabdomere formation, this study has identified the Drosophila
mob2 (Dmob2) gene. Dmob2 belongs to a Mob1/phocein domain protein family whose
functions are involved in polarized cell growth and asymmetric cell fate determination in
yeast. To study the role of Dmob2 in photoreceptor development, we have raised an
antibody against the Dmob2 protein. An immunocytochemical study has shown that
Dmob2 is mainly localized in the apical membrane of photoreceptor cells during early
development. As development proceeds, Dmob2 is gradually confined to the rhabdomere
base of the photoreceptor cells. RNA interference (RNAi) for knockdown Dmob2
expression during eye development impairs rhabdomere formation. Our study further
shows that the subcellular localization of phosphorylated Moesin and Crumbs in the
developing photoreceptor cell is disrupted in Dmob2 RNAi flies. This work thus reports a
novel function of Dmob2 in photoreceptor cell development.
13
http://www.springerlink.com/content/6271281k45685307/
17.Visualization of Individual Scr mRNAs during Drosophila Embryogenesis
Yields Evidence for Transcriptional Bursting
Adam Paré1,, Derek Lemons1, Dave Kosman1, William Beaver2, Yoav Freund2 and William McGinnis1,
1
Section of Cell and Developmental Biology, Division of Biology, University of California, San Diego, La
Jolla, CA 92093, USA
2
Department of Computer Science and Engineering, University of California, San Diego, La Jolla, CA
92093, USA
The detection and counting of transcripts within single cells via fluorescent in situ
hybridization (FISH) [1,2,3,4,5,6] has allowed researchers to ask quantitative questions
about gene expression at the level of individual cells. This method is often preferable to
quantitative RT-PCR [7,8,9], because it does not necessitate destruction of the cells
being probed and maintains spatial information that may be of interest. Until now,
studies using FISH at single-molecule resolution have only been rigorously carried out in
isolated cells (e.g., yeast cells or mammalian cell culture). Here, we describe the
detection and counting of transcripts within single cells of fixed, whole-mount Drosophila
embryos via a combination of FISH, immunohistochemistry, and image segmentation.
Our method takes advantage of inexpensive, long RNA probes detected with antibodies
[10,11], and we present novel evidence to show that we can robustly detect single mRNA
molecules. We use this method to characterize transcription at the endogenous locus of
the Hox gene Sex combs reduced (Scr), by comparing a stably expressing group of cells
to a group that only transiently expresses the gene. Our data provide evidence for
transcriptional bursting [2,5,12,13,14,15,16], as well for divergent “accumulation” and
“maintenance” phases of gene activity at the Scr locus.
http://www.cell.com/current-biology/abstract/S0960-9822%2809%2901848-X
18.Hedgehog, but not Odd skipped, induces segmental grooves in the
Drosophila epidermis
Shai Mulinari and Udo Häcker*[email protected]
Department of Experimental Medical Science and Lund Strategic Research Center for Stem Cell Biology
and Cell Therapy, Lund University,BMC B13, 22184 Lund, Sweden
The formation of segmental grooves during mid embryogenesis in the Drosophila
epidermis depends on the specification of a single row of groove cells posteriorly adjacent
to cells that express the Hedgehog signal. However, the mechanism of groove formation
and the role of the parasegmental organizer, which consists of adjacent rows of
hedgehog- and wingless-expressing cells, are not well understood. We report that
although groove cells originate from a population of Odd skipped-expressing cells, this
pair-rule transcription factor is not required for their specification. We further find that
Hedgehog is sufficient to specify groove fate in cells of different origin as late as stage 10,
suggesting that Hedgehog induces groove cell fate rather than maintaining a preestablished state. Wingless activity is continuously required in the posterior part of
parasegments to antagonize segmental groove formation. Our data support an
instructive role for the Wingless/Hedgehog organizer in cellular patterning.
http://dev.biologists.org/content/136/23/3875.abstract
19.Sanpodo: a context-dependent activator and inhibitor of Notch signaling
during asymmetric divisions
14
A. Burcu Babaoglan1,2,Kate M. O'Connor-Giles3,Hemlata Mistry4, Adam Schickedanz2, Beth A.
Wilson2 and James B. Skeath2,* [email protected]
1
Program in Developmental Biology, Washington University School of Medicine, St Louis, MO 63110,
USA
2
Department of Genetics, Washington University School of Medicine, St Louis, MO 63110, USA
3
Laboratories of Genetics and Molecular Biology, University of Wisconsin,1525 Linden Drive, Madison,
WI 53706, USA
4
Department of Biology, Widener University, Chester, PA 19013, USA
Asymmetric cell divisions generate sibling cells of distinct fates (‘A’, ‘B’) and constitute a
fundamental mechanism that creates cell-type diversity in multicellular organisms.
Antagonistic interactions between the Notch pathway and the intrinsic cell-fate
determinant Numb appear to regulate asymmetric divisions in flies and vertebrates.
During these divisions, productive Notch signaling requires sanpodo, which encodes a
novel transmembrane protein. Here, we demonstrate that Drosophila sanpodo plays a
dual role to regulate Notch signaling during asymmetric divisions — amplifying Notch
signaling in the absence of Numb in the ‘A’ daughter cell and inhibiting Notch signaling in
the presence of Numb in the ‘B’ daughter cell. In so doing, sanpodo ensures the
asymmetry in Notch signaling levels necessary for the acquisition of distinct fates by the
two daughter cells. These findings answer long-standing questions about the restricted
ability of Numb and Sanpodo to inhibit and to promote, respectively, Notch signaling
during asymmetric divisions.
20.The cadherin Fat2 is required for planar cell polarity in the Drosophila
ovary
Ivana Viktorinová, Tina König*, Karin Schlichting and Christian Dahmann† [email protected]
Max Planck Institute of Molecular Cell Biology and Genetics,Pfotenhauerstrasse 108, 01307 Dresden,
Germany
Planar cell polarity is an important characteristic of many epithelia. In the Drosophila
wing, eye and abdomen, establishment of planar cell polarity requires the core planar cell
polarity genes and two cadherins, Fat and Dachsous. Drosophila Fat2 is a cadherin
related to Fat; however, its role during planar cell polarity has not been studied. Here,
we have generated mutations in fat2 and show that Fat2 is required for the planar
polarity of actin filament orientation at the basal side of ovarian follicle cells. Defects in
actin filament orientation correlate with a failure of egg chambers to elongate during
oogenesis. Using a functional fosmid-based fat2-GFP transgene, we show that the
distribution of Fat2 protein in follicle cells is planar polarized and that Fat2 localizes
where basal actin filaments terminate. Mosaic analysis demonstrates that Fat2 acts nonautonomously in follicle cells, indicating that Fat2 is required for the transmission of
polarity information. Our results suggest a principal role for Fat-like cadherins during the
establishment of planar cell polarity.
21.Effete-mediated degradation of Cyclin A is essential for the maintenance
of germline stem cells in Drosophila
Dongsheng Chen*, Qi Wang*, Haidong Huang*,Laixin Xia, Xiaoyong Jiang, Lijuan Kan, Qinmiao Sun
and Dahua Chen† [email protected]
State Key Laboratory of Reproductive Biology and State Key Laboratory of Biomembrane and
Membrane Biotechnology, Institute of Zoology, Chinese Academy of Sciences,Datun Road, Chaoyang,
Beijing 100101, P.R. China
15
Increasing evidence supports the idea that the regulation of stem cells requires both
extrinsic and intrinsic mechanisms. However, much less is known about how intrinsic
signals regulate the fate of stem cells. Studies on germline stem cells (GSCs) in the
Drosophila ovary have provided novel insights into the regulatory mechanisms of stem
cell maintenance. In this study, we demonstrate that a ubiquitin-dependent pathway
mediated by the Drosophila eff gene, which encodes the E2 ubiquitin-conjugating enzyme
Effete (Eff), plays an essential role in GSC maintenance. We show that Eff both physically
and genetically interacts with dAPC2, a key component of the anaphase-promoting
complex (APC), which acts as a multisubunit E3 ligase and plays an essential role in
targeting mitotic regulators for degradation during exit from mitosis. This interaction
indicates that Eff regulates the APC/C-mediated proteolysis pathway in GSCs. Moreover,
we show that expression of a stable form of Cyclin A, but not full-length Cyclin A, results
in GSC loss. Finally we show that, in common with APC2, Eff is required for the
ubiquitylation of Cyclin A, and overexpression of full-length Cyclin A accelerates the loss
of GSCs in the eff mutant background. Collectively, our data support the idea that
Effete/APC-mediated degradation of Cyclin A is essential for the maintenance of germline
stem cells in Drosophila. Given that the regulation of mitotic Cyclins is evolutionarily
conserved between flies and mammals, our study also implies that a similar mechanism
may be conserved in mammals.
22.Drosophila laminins act as key regulators of basement membrane
assembly and morphogenesis
Jose M. Urbano1,*, Catherine N. Torgler1,4,*, Cristina Molnar2,*, Ulrich Tepass3, Ana López-Varea2,
Nicholas H. Brown4, Jose F. de Celis2 and Maria D. Martín-Bermudo1,† ([email protected]
1
Centro Andaluz de Biología de Desarrollo (CABD), Univ. Pablo de Olavide-CSIC, Ctra. Utrera Km. 1,
41013 Sevilla, Spain
2
Centro de Biología Molecular ‘Severo Ochoa’, CSIC and Universidad Autónoma de Madrid, Cantoblanco,
Madrid 28049, Spain
3
Department of Cell and Systems Biology, University of Toronto,Toronto, Ontario M5S 3G5, Canada
4
The Gurdon Institute and Department of Physiology, Development & Neuroscience, University of
Cambridge,Tennis Court Road, Cambridge CB2 1QN, UK
Laminins are heterotrimeric molecules found in all basement membranes. In mammals,
they have been involved in diverse developmental processes, from gastrulation to tissue
maintenance. The Drosophila genome encodes two laminin α chains, one β and one Γ,
which form two distinct laminin trimers. So far, only mutations affecting one or other
trimer have been analysed. In order to study embryonic development in the complete
absence of laminins, we mutated the gene encoding the sole laminin β chain in
Drosophila, LanB1, so that no trimers can be made. We show that LanB1 mutant
embryos develop until the end of embryogenesis. Electron microscopy analysis of mutant
embryos reveals that the basement membranes are absent and the remaining
extracellular material appears disorganised and diffuse. Accordingly, abnormal
accumulation of major basement membrane components, such as Collagen IV and
Perlecan, is observed in mutant tissues. In addition, we show that elimination of LanB1
prevents the normal morphogenesis of most organs and tissues, including the gut,
trachea, muscles and nervous system. In spite of the above structural roles for laminins,
our results unravel novel functions in cell adhesion, migration and rearrangement. We
propose that while an early function of laminins in gastrulation is not conserved in
Drosophila and mammals, their function in basement membrane assembly and
organogenesis seems to be maintained throughout evolution.
16
23.Control in time and space: Tramtrack69 cooperates with Notch and
Ecdysone to repress ectopic fate and shape changes during Drosophila
egg chamber maturation
Michael J. Boyle1 and Celeste A. Berg1,2,* [email protected]
1
Molecular and Cellular Biology Program, University of Washington, Box 355065, Seattle, WA 981955065, USA
2
Department of Genome Sciences, University of Washington,Box 355065, Seattle, WA 98195-5065,
USA
Organ morphogenesis requires cooperation between cells, which determine their course
of action based upon location within a tissue. Just as important, cells must synchronize
their activities, which requires awareness of developmental time. To understand how
cells coordinate behaviors in time and space, we analyzed Drosophila egg chamber
development. We found that the transcription factor Tramtrack69 (TTK69) controls the
fates and shapes of all columnar follicle cells by integrating temporal and spatial
information, restricting characteristic changes in morphology and expression that occur
at stage 10B to appropriate domains. TTK69 is required again later in oogenesis: it
controls the volume of the dorsal-appendage (DA) tubes by promoting apical reexpansion and lateral shortening of DA-forming follicle cells. We show that TTK69 and
Notch compete to repress each other's expression and that a local Ecdysone signal is
required to shift the balance in favor of TTK69. We hypothesize that TTK69 then
cooperates with spatially restricted co-factors to define appropriate responses to a
globally available (but as yet unidentified) temporal signal that initiates the S10B
transformations.
24.Vasa promotes Drosophila germline stem cell differentiation by activating
mei-P26 translation by directly interacting with a (U)-rich motif in its 3′
UTR
Niankun Liu, Hong Han and Paul Lasko
Department of Biology, Developmental Biology Research Initiative, and Goodman Cancer Centre, McGill
University, Montreal, Quebec H3A 1B1, Canada
Vasa (Vas) is a DEAD-box RNA-binding protein required in Drosophila at several steps of
oogenesis and for primordial germ cell (PGC) specification. Vas associates with eukaryotic
initiation factor 5B (eIF5B), and this interaction has been implicated in translational
activation of gurken mRNA in the oocyte. Vas is expressed in all ovarian germline cells,
and aspects of the vas-null phenotype suggest a function in regulating the balance
between germline stem cells (GSCs) and their fate-restricted descendants. We used a
biochemical approach to recover Vas-associated mRNAs and obtained mei-P26, whose
product represses microRNA activity and promotes GSC differentiation. We found that
vas and mei-P26 mutants interact, and that mei-P26 translation is substantially reduced
in vas mutant cells. In vitro, Vas protein bound specifically to a (U)-rich motif in the meiP26 3′ untranslated region (UTR), and Vas-dependent regulation of GFP-mei-P26
transgenes in vivo was dependent on the same (U)-rich 3′ UTR domain. The ability of Vas
to activate mei-P26 expression in vivo was abrogated by a mutation that greatly reduces
its interaction with eIF5B. Taken together, our data support the conclusion that Vas
promotes germ cell differentiation by directly activating mei-P26 translation in earlystage committed cells.
Genes & Dev. 2009. 23: 2742-2752
http://genesdev.cshlp.org/content/23/23/2742.abstract
17
Top
Insect Ecology
25.Phase-dependent outbreak dynamics of geometrid moth linked to host
plant phenology
Jane U. Jepsen1,2,*,Snorre B. Hagen1, Stein-Rune Karlsen3 and Rolf A. [email protected]
1. Department of Biology, University of Tromsø, N-9037 Tromsø, Norway
2. Polar Environmental Centre, Norwegian Institute for Nature Research, N-9296 Tromsø, Norway
3. Norut, Northern Research Institute Tromsø, PO Box 6424, N-9294 Tromsø, Norway
Climatically driven Moran effects have often been invoked as the most likely cause of
regionally synchronized outbreaks of insect herbivores without identifying the exact
mechanism. However, the degree of match between host plant and larval phenology is
crucial for the growth and survival of many spring-feeding pest insects, suggesting that a
phenological match/mismatch-driven Moran effect may act as a synchronizing agent.
We analyse the phase-dependent spatial dynamics of defoliation caused by cyclically
outbreaking geometrid moths in northern boreal birch forest in Fennoscandia through the
most recent massive outbreak (2000–2008). We use satellite-derived time series of the
prevalence of moth defoliation and the onset of the growing season for the entire region
to investigate the link between the patterns of defoliation and outbreak spread. In
addition, we examine whether a phase-dependent coherence in the pattern of spatial
synchrony exists between defoliation and onset of the growing season, in order to
evaluate if the degree of matching phenology between the moth and their host plant
could be the mechanism behind a Moran effect.
The strength of regional spatial synchrony in defoliation and the pattern of defoliation
spread were both highly phase-dependent. The incipient phase of the outbreak was
characterized by high regional synchrony in defoliation and long spread distances,
compared with the epidemic and crash phase. Defoliation spread was best described
using a two-scale stratified spread model, suggesting that defoliation spread is governed
by two processes operating at different spatial scale. The pattern of phase-dependent
spatial synchrony was coherent in both defoliation and onset of the growing season. This
suggests that the timing of spring phenology plays a role in the large-scale
synchronization of birch forest moth outbreaks.
http://rspb.royalsocietypublishing.org/content/276/1676/4119.abstract
Top
Insect Evolution
26.Repeated Co-options of Exoskeleton Formation during Wing-to-Elytron
Evolution in Beetles
Yoshinori Tomoyasu1, 4,, Yasuyuki Arakane2, Karl J. Kramer2, 3 and Robin E. Denell1
1
Division of Biology, Kansas State University, Manhattan, KS 66506, USA
2
Department of Biochemistry, Kansas State University, Manhattan, KS 66506, USA
3
Grain Marketing and Production Research Center, Agricultural Research Service, United States
Department of Agriculture, 1515 College Avenue, Manhattan, KS 66502, USA
The vast diversity in morphology of insect wings provides an excellent model to study
morphological evolution. The best-described wing modification is the specification of
halteres in Drosophila by a Hox-dependent mechanism, in which a Hox gene affects the
expression of genes important for wing development to modify the resulting structure.
We have previously shown that highly modified beetle elytra are Hox-free structures
despite their divergent morphology, suggesting another mode of evolutionary
modification.To understand how elytra have evolved without Hox input, we have
analyzed wing development in a coleopteran, Tribolium castaneum. Based on Drosophila
mutant phenotypes, we first hypothesized that changes in the wing gene network might
18
have contributed to elytral evolution. However, we found that the wing gene network
defined in Drosophila is largely conserved in Tribolium and is also used to pattern the
elytra. Instead, we found evidence that the exoskeleton formation has been co-opted
downstream of the conserved wing gene network multiple times. We also show evidence
that one of these co-options happened prior to the others, suggesting that repeated cooptions may have strengthened an advantageous trait. In addition, we found that the
Tribolium apterous genes are not only essential for exoskeletalization of the elytra but
also are required for the proper identity of the hindwing—an unexpected role that we find
to be conserved in Drosophila.Our findings suggest that elytral evolution has been
achieved by co-opting a beneficial trait several times while conserving the main
framework of wing patterning genes.
27.EFFECTS OF PARTHENOGENESIS AND GEOGRAPHIC ISOLATION ON
FEMALE SEXUAL TRAITS IN A PARASITOID WASP
Ken Kraaijeveld 1,2 , Padu Franco 1 , Barbara M. Reumer 1 , and Jacques J. M. van Alphen 1,3
1
Animal Ecology, Institute of Biology, University of Leiden, PO Box 9516, 2300 RA Leiden, The
Netherlands 2 E-mail: [email protected] 3 UMR 6553 ECOBIO, Université de Rennes
I, Campus de Beaulieu, Avenue du Général Leclerc, 35 042 Rennes cedex, France
Population divergence in sexual traits is affected by different selection pressures,
depending on the mode of reproduction. In allopatric sexual populations, aspects of
sexual behavior may diverge due to sexual selection. In parthenogenetic populations,
loss-of-function mutations in genes involved in sexual functionality may be selectively
neutral or favored by selection. We assess to what extent these processes have
contributed to divergence in female sexual traits in the parasitoid wasp Leptopilina
clavipes in which some populations are infected with parthenogenesis-inducing Wolbachia
bacteria. We find evidence consistent with both hypotheses. Both arrhenotokous males
and males derived from thelytokous strains preferred to court females from their own
population. This suggests that these populations had already evolved population-specific
mating preferences when the latter became parthenogenetic. Thelytokous females did
not store sperm efficiently and fertilized very few of their eggs. The nonfertility of
thelytokous females was due to mutations in the wasp genome, which must be an effect
of mutation accumulation under thelytoky. Divergence in female sexual traits of these
two allopatric populations has thus been molded by different forces: independent
male/female coevolution while both populations were still sexual, followed by female-only
evolution after one population switched to parthenogenesis.
http://www3.interscience.wiley.com/journal/122526547/abstract
28.THE TEMPO AND MODE OF EVOLUTION OF TRANSPOSABLE ELEMENTS AS
REVEALED BY MOLECULAR PHYLOGENIES RECONSTRUCTED FROM
MOSQUITO GENOMES
Claudio J. Struchiner 1,2 , Eduardo Massad 3,4 , Zhijian Tu 5,6 , and José M. C. Ribeiro 7,8
1
ENSP/FIOCRUZ and IMS/UERJ, Av. Brasil, 4365, Rio de Janeiro, Braxil 21040 360 2 E-mail: [email protected] 3 FM/USP, Av. Dr. Arnaldo,
455, São Paulo, Braxil 01246 903 4 E-mail: [email protected] 5 Department of Biochemistry, Virginia Polytechnic Institute and
State University, 309 Engel Hall, Blacksburg, Virginia 24061 6 E-mail: [email protected] 7 Laboratory of Malaria and Vector Research,
National Institute of Allergy and Infectious Diseases, 12735 Twinbrook Parkway, Room 2E32D, National Institutes of Health, Rockville,
Maryland 20852 8 E-mail: [email protected]
Although many mathematical models exist predicting the dynamics of transposable
elements (TEs), there is a lack of available empirical data to validate these models and
inherent assumptions. Genomes can provide a snapshot of several TE families in a single
organism, and these could have their demographics inferred by coalescent analysis,
allowing for the testing of theories on TE amplification dynamics. Using the available
19
genomes of the mosquitoes Aedes aegypti and Anopheles gambiae, we indicate that such
an approach is feasible. Our analysis follows four steps: (1) mining the two mosquito
genomes currently available in search of TE families; (2) fitting, to selected families
found in (1), a phylogeny tree under the general time-reversible (GTR) nucleotide
substitution model with an uncorrelated lognormal (UCLN) relaxed clock and a
nonparametric demographic model; (3) fitting a nonparametric coalescent model to the
tree generated in (2); and (4) fitting parametric models motivated by ecological theories
to the curve generated in (3).
29.EVOLUTION OF IDENTITY SIGNALS: FREQUENCY-DEPENDENT BENEFITS
OF DISTINCTIVE PHENOTYPES USED FOR INDIVIDUAL RECOGNITION
Michael J. Sheehan 1,2 and Elizabeth A. Tibbetts 1,3
1
Ecology and Evolutionary Biology, University of Michigan, 830 N. University Avenue, Ann Arbor,
Michigan 48109 2 E-mail: [email protected] 3 E-mail: [email protected]
Identifying broad-scale evolutionary processes that maintain phenotypic polymorphisms
has been a major goal of modern evolutionary biology. There are numerous mechanisms,
such as negative frequency-dependent selection, that may maintain polymorphisms,
although it is unknown which mechanisms are prominent in nature. Traits used for
individual recognition are strikingly variable and have evolved independently in numerous
lineages, providing an excellent model to investigate which factors maintain ecologically
relevant phenotypic polymorphisms. Theoretical models suggest that individuals may
benefit by advertising their identities with distinctive, recognizable phenotypes. Here, we
test the benefits of advertising one's identity with a distinctive phenotype. We
manipulated the appearance of Polistes fuscatus paper wasp groups so that three
individuals had the same appearance and one individual had a unique, easily
recognizable appearance. We found that individuals with distinctive appearances received
less aggression than individuals with nondistinctive appearances. Therefore, individuals
benefit by advertising their identity with a unique phenotype. Our results provide a
potential mechanism through which negative frequency-dependent selection may
maintain the polymorphic identity signals in P. fuscatus. Given that recognition is
important for many social interactions, selection for distinctive identity signals may be an
underappreciated and widespread mechanism underlying the evolution of phenotypic
polymorphisms in social taxa.
Evolution Volume 63 Issue 12, Pages 3106 – 3113 Published Online: 9 Sep 2009
30.Bacterial gut symbionts are tightly linked with the evolution of herbivory
in ants
Jacob A. Russella,b,1,2, Corrie S. Moreaua,c,1, Benjamin Goldman-Huertasa, Mikiko Fujiwaraa, David J.
Lohmana,d and Naomi E. Piercea [email protected]
a
Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge,
MA 02138;
b
Department of Biology, Drexel University, Philadelphia, PA 19104;
c
Department of Zoology, Field Museum of Natural History, 1400 South Lake Shore Drive, Chicago, IL
60605; and
d
Department of Biology, The City College of The City University of New York, Convent Avenue at 138th
Street, New York, NY 10031
Ants are a dominant feature of terrestrial ecosystems, yet we know little about the forces
that drive their evolution. Recent findings illustrate that their diets range from
herbivorous to predaceous, with “herbivores” feeding primarily on exudates from plants
and sap-feeding insects. Persistence on these nitrogen-poor food sources raises the
20
question of how ants obtain sufficient nutrition. To investigate the potential role of
symbiotic microbes, we have surveyed 283 species from 18 of the 21 ant subfamilies
using molecular techniques. Our findings uncovered a wealth of bacteria from across the
ants. Notable among the surveyed hosts were herbivorous “turtle ants” from the related
genera Cephalotes and Procryptocerus (tribe Cephalotini). These commonly harbored
bacteria from ant-specific clades within the Burkholderiales, Pseudomonadales,
Rhizobiales, Verrucomicrobiales, and Xanthomonadales, and studies of lab-reared
Cephalotes varians characterized these microbes as symbiotic residents of ant guts.
Although most of these symbionts were confined to turtle ants, bacteria from an antspecific clade of Rhizobiales were more broadly distributed. Statistical analyses revealed
a strong relationship between herbivory and the prevalence of Rhizobiales gut symbionts
within ant genera. Furthermore, a consideration of the ant phylogeny identified at least
five independent origins of symbioses between herbivorous ants and related Rhizobiales.
Combined with previous findings and the potential for symbiotic nitrogen fixation, our
results strongly support the hypothesis that bacteria have facilitated convergent
evolution of herbivory across the ants, further implicating symbiosis as a major force in
ant evolution.
31.Ejaculate components delay reproductive senescence while elevating
female reproductive rate in an insect
Klaus Reinhardt1, Richard A. Naylor and Michael T. Siva-Jothy [email protected]
Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 2TN,
United Kingdom
Increased female reproductive rates usually result in accelerated senescence. This
correlation provides a link between the evolutionary conflict of the sexes and aging when
ejaculate components elevate female reproductive rates at the cost of future
reproduction. It is not clear whether this female cost is manifest as shorter lifespan or an
earlier onset or a steeper rate of reproductive senescence. It also is unclear whether
beneficial ejaculates release females from reproductive trade-offs and, if so, which
senescence parameters are affected. We examined these issues in the bedbug, Cimex
lectularius, a long-lived insect that shows reduced female lifespan as well as female
reproductive senescence at the male-determined mating frequency. We demonstrate
experimentally that, independently of the mating frequency, females receiving more
ejaculate show increased reproductive rates and enter reproductive senescence later
than females receiving less ejaculate. The rate of reproductive senescence did not differ
between treatments, and reproductive rates did not predict mortality. The ejaculate
effects were consistent in inter- and intra-population crosses, suggesting they have not
evolved recently and are not caused by inbreeding. Our results suggest that ejaculate
components compensate for the costs of elevated female reproductive rates in bedbugs
by delaying the onset of reproductive senescence. Ejaculate components that are
beneficial to polyandrous females could have arisen because male traits that protect the
ejaculate have positive pleiotropic effects and/or because female counteradaptations to
antagonistic male traits exceed the neutralization of those traits. That males influence
female reproductive senescence has important consequences for trade-offs between
reproduction and longevity and for studies of somatic senescence.
21
Top
Insect Genetics
32.Little Effect of the tan Locus on Pigmentation in Female Hybrids between
Drosophila santomea and D. melanogaster
Daniel R. Matute1, Ian A. Butler1 and Jerry A. Coyne1,
1
Department of Ecology and Evolution, The University of Chicago, 1101 E. 57 Street, Chicago, IL
60637, USA
Previous work on Drosophila santomea suggested that its absence of abdominal
pigmentation, compared to the other darkly pigmented species, is based on mutations in
the cis-regulatory region of tan, inactivating the expression of that gene in the abdomen
of D. santomea males and females. Our discovery that D. santomea males can produce
viable hybrids when mated to D. melanogaster females enables us to use the
armamentarium of genetic tools in the latter species to study the genetic basis of this
interspecific difference in pigmentation. Hybridization tests using D. melanogaster
deficiencies that include tan show no evidence that this locus is involved in the lighter
pigmentation of D. santomea females; rather, the pigmentation difference appears to
involve at least four other loci in the region. Earlier results implicating tan may have been
based on a type of transgenic analysis that can give misleading results about the genes
involved in an evolutionary change.
http://www.cell.com/abstract/S0092-8674%2809%2901359-2
33.Evolution of the tan Locus Contributed to Pigment Loss in Drosophila
santomea: A Response to Matute et al.
Mark Rebeiz1, 5, Margarita Ramos-Womack2, 5, Sangyun Jeong1, 6, Peter Andolfatto3, Thomas
Werner1, John True4, David L. Stern2 and Sean B. Carroll1,
1
Howard Hughes Medical Institute and Laboratory of Molecular Biology, University of Wisconsin, 1525
Linden Drive, Madison, WI 53706 USA
2
Howard Hughes Medical Institute and Department of Ecology and Evolutionary Biology, Princeton
University, Princeton, NJ 08544, USA
3
Department of Ecology and Evolutionary Biology and the Lewis-Sigler Institute of Integrative
Genomics, Princeton University, Princeton, NJ 08544, USA
4
Department of Ecology and Evolution, Stony Brook University, Stony Brook, NY 11794 USA
We have shown previously that the loss of abdominal pigmentation in D. santomea
relative to its sister species D. yakuba resulted, in part, from cis-regulatory mutations at
the tan locus. Matute et al. claim, based solely upon extrapolation from genetic crosses
of D. santomea and D. melanogaster, a much more divergent species, that at least four X
chromosome regions but not tan are responsible for pigmentation differences. Here, we
provide additional evidence from introgressions of D. yakuba genes into D. santomea
that support a causative role for tan in the loss of pigmentation and present analyses
that contradict Matute et al.'s claims. We discuss how the choice of parental species and
other factors affect the ability to identify loci responsible for species divergence, and we
affirm that all of our previously reported results and conclusions stand.
http://www.cell.com/abstract/S0092-8674(09)01377-4
34.X-Linked Variation in Immune Response in Drosophila melanogaster
Erin M. Hill-Burns1 and Andrew G. Clark [email protected]
Field of Genetics and Development, Department of Molecular Biology and Genetics, Cornell University,
Ithaca, New York 14853
22
This study quantifies the effects of naturally occurring X-linked variation on immune
response in Drosophila melanogaster to assess associations between immunity genotypes
and innate immune response. We constructed a set of 168 X-chromosomal extraction
lines, incorporating X chromosomes from a natural population into co-isogenic autosomal
backgrounds, and genotyped the lines at 88 SNPs in 20 X-linked immune genes. We find
that genetic variation in many of the genes is associated with immune response
phenotypes, including bacterial load and immune gene expression. Many of the
associations act in a sex-specific or sexually antagonistic manner, supporting the theory
that with the selective pressures facing genes on the X chromosome, sexually
antagonistic variation may be more easily maintained.
Genetics, Vol. 183, 1477-1491, December 2009
http://www.genetics.org/cgi/content/abstract/183/4/1477?etoc
35.Altered Heterochromatin Binding by a Hybrid Sterility Protein in
Drosophila Sibling Species
Joshua J. Bayes1,2,* and Harmit S. Malik2,3, [email protected]
1
Molecular and Cellular Biology Program, University of Washington, Seattle, WA 98185, USA.
2
Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
3
Howard Hughes Medical Institute, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
Hybrid sterility of the heterogametic sex is one of the first postzygotic reproductive
barriers to evolve during speciation, yet the molecular basis of hybrid sterility is poorly
understood. We show that the hybrid male sterility gene Odysseus-site homeobox (OdsH)
encodes a protein that localizes to evolutionarily dynamic loci within heterochromatin and
leads to their decondensation. In Drosophila mauritiana x Drosophila simulans male
hybrids, OdsH from D. mauritiana (OdsHmau) acts as a sterilizing factor by associating
with the heterochromatic Y chromosome of D. simulans, whereas D. simulans OdsH
(OdsHsim) does not. Characterization of sterile hybrid testes revealed that OdsH
abundance and localization in the premeiotic phases of spermatogenesis differ between
species. These results reveal that rapid heterochromatin evolution affects the onset of
hybrid sterility.
Science 11 December 2009 Vol. 326. no. 5959, pp. 1538 – 1541
http://www.sciencemag.org/cgi/content/abstract/326/5959/1538?sa_campaign=Email/to
c/11-December-2009/10.1126/science.1181756
Top
Insect Hearing
36. The cost of assuming the life history of a host: acoustic startle in the
parasitoid fly Ormia ochracea
M. J. Rosen1,*, E. C. Levin2 and R. R. Hoy2 [email protected]
1
Center for Neural Science, New York University, New York, NY 10003, USA
2
Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA
In the obligatory reproductive dependence of a parasite on its host, the parasite must
trade the benefit of ‘outsourcing’ functions like reproduction for the risk of assuming
hazards associated with the host. In the present study, we report behavioral adaptations
of a parasitic fly, Ormia ochracea, that resemble those of its cricket hosts. Ormia females
home in on the male cricket's songs and deposit larvae, which burrow into the cricket,
feed and emerge to pupate. Because male crickets call at night, gravid female Ormia in
search of hosts are subject to bat predation, in much the same way as female crickets
are when responding to male song. We show that Ormia has evolved the same evasive
behavior as have crickets: an acoustic startle response to bat-like ultrasound that
manifests clearly only during flight. Furthermore, like crickets, Ormia has a sharp
23
response boundary between the frequencies of song and bat cries, resembling categorical
perception first described in the context of human speech.
http://jeb.biologists.org/cgi/content/abstract/212/24/4056?etoc
37. Moths are not silent, but whisper ultrasonic courtship songs
R. Nakano1,*, , T. Takanashi2, T. Fujii1, N. Skals3, A. Surlykke4 and Y. Ishikawa1 [email protected]
1
Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 1138657, Japan
2
Department of Forest Entomology, Forestry and Forest Products Research Institute, Tsukuba, Ibaraki
305-8687, Japan
3
Vedbendvænget 6, DK-5800 Nyborg, Denmark
4
Center for Sound Communication, Institute of Biology, University of Southern Denmark, DK-5230,
Odense M, Denmark
Ultrasonic hearing is widespread among moths, but very few moth species have been
reported to produce ultrasounds for sexual communication. In those that do, the signals
are intense and thus well matched for long distance communication. By contrast, males of
the Asian corn borer moth (Crambidae) were recently shown to whisper extremely lowintensity ultrasonic courtship songs close to females. Since low sound levels will prevent
eavesdropping by predators, parasites and conspecific rivals, we predicted low intensity
ultrasound communication to be widespread among moths. Here we tested 13 species of
moths including members of the Noctuidae, Arctiidae, Geometridae and Crambidae. Males
of nine species, 70%, produced broadband ultrasound close to females. Peak frequencies
ranged from 38 to above 100 kHz. All sounds were of low intensity, 43-76 dB SPL at 1 cm
[64±10 dB peSPL (mean ± s.d.), N=9 species]. These quiet and/or hyper-frequency
ultrasounds are audible to nearby mates, but inaudible to unintended receivers. Although
largely unknown because it is so inconspicuous, acoustic communication using low
intensity ultrasound appears to be widespread among hearing moths. Thus, acoustic
communication may be the norm rather than the exception.
Key words: acoustic communication, courtship behavior, low sound level, moths,
ultrasound
38. The next step in cicada audition: measuring pico-mechanics in the
cicada's ear
J. F. C. Windmill1,*, J. Sueur2 and D. Robert3 [email protected]
1
Centre for Ultrasonic Engineering, Department of Electronic & Electrical Engineering, University of
Strathclyde, 204 George Street, Glasgow, G1 1XW, UK
2
Muséum National d'Histoire Naturelle, Département Systématique et Evolution, UMR 7205 CNRS, 45
rue Buffon, F-75231 Paris cedex 05, France
3
School of Biological Sciences, University of Bristol, Woodland Road, Bristol, BS8 1UG, UK
Female cicadas use sound when they select a mate from a chorus of singing males. The
cicada has a tympanal ear; and the tympanal membrane, and constituent tympanal ridge,
act as both acousto-mechanical transducers and frequency filters. The tympanal ridge is
physically connected to a large number of mechanoreceptor neurons via a cuticular
extension known as the tympanal apodeme. Using microscanning laser Doppler
vibrometry, we measured for the first time the in vivo vibrations of the apodeme of
female Cicadatra atra in response to the motion of the tympanum driven by sound. These
measurements reveal that the nanoscale motion of the tympanal membrane is over a
magnitude greater than that of the apodeme. Furthermore, the apodeme acts as an
additional mechanical frequency filter, enhancing that of the tympanal ridge, narrowing
the frequency band of vibration at the mechanoreceptor neurons to that of the male
24
calling song. This study enhances our understanding of the mechanical link between the
external ear of the cicada and its sensory cells.
39. Acoustical mimicry in a predatory social parasite of ants
F. Barbero1,2, S. Bonelli1, J. A. Thomas3, E. Balletto1 and K. Schönrogge2 [email protected]
1
Department of Animal and Human Biology, University of Turin, 10123 Turin, Italy
2
Centre for Ecology and Hydrology, Maclean Building, Wallingford, Oxfordshire, OX10 8BB, UK
3
Department of Zoology, University of Oxford, Tinbergen Building, Oxford, OX1 3PS, UK
Rapid, effective communication between colony members is a key attribute that enables
ants to live in dominant, fiercely protected societies. Their signals, however, may be
mimicked by other insects that coexist as commensals with ants or interact with them as
mutualists or social parasites. We consider the role of acoustics in ant communication and
its exploitation by social parasites. Social parasitism has been studied mainly in the
butterfly genus Maculinea, the final instar larvae of which are host-specific parasites of
Myrmica ants, preying either on ant grubs (predatory Maculinea) or being fed by
trophallaxis (cuckoo Maculinea). We found similar significant differences between the
stridulations of model queen and worker ant castes in both Myrmica sabuleti and Myrmica
scabrinodis to that previously reported for Myrmica schencki. However, the sounds made
by queens of all three Myrmica species were indistinguishable, and among workers,
stridulations did not differ significantly in two of three species-pairs tested. Sounds
recorded from the predatory caterpillars and pupae of Maculinea arion had similar or
closer patterns to the acoustics of their host Myrmica sabuleti than those previously
reported for the cuckoo Maculinea rebeli and its host Myrmica schencki, even though
Maculinea rebeli caterpillars live more intimately with their host. We conclude that
chemical mimicry enables Maculinea larvae to be accepted as colony members by worker
ants, but that caterpillars and pupae of both predatory and cuckoo butterflies employ
acoustical mimicry of queen ant calls to elevate their status towards the highest
attainable position within their host's social hierarchy.
40. Evaluation of amplitude in male song: female waxmoths respond to
fortissimo notes
D. Limousin* and M. D. Greenfield [email protected]
Institut de recherche sur la biologie de l'insecte (IRBI), CNRS UMR 6035, Université François Rabelais
de Tours, Parc de Grandmont, 37200 Tours, France
Female evaluation of male signals in the context of sexual selection is often made on the
basis of signal energy. Particularly in acoustic species, females may prefer male song that
is broadcast at greater amplitude or power. However, song amplitude may be represented
by various parameters, and the specific one(s) that are evaluated are not clear. We
addressed this problem in an acoustic moth, Achroia grisella (Lepidoptera: Pyralidae),
where males attract females with trains of paired ultrasonic pulses. Previous studies
showed that females prefer songs that include pulse pairs that have greater mean peak
amplitude and that are delivered with greater power (=mean peak amplitudexpulse-pair
rate). Here, we report that given male songs of equal acoustic power, females prefer
songs in which some pulses attain peak amplitudes that exceed the mean value and that
this preference depends largely on the magnitude of amplitude fluctuation. We measured
significant variation among males in their degree of amplitude fluctuation, and we note
that males that broadcast with lower acoustic power typically show greater relative
fluctuations and attain relatively higher amplitude maxima. We discuss the potential role
25
of multiple integration time constants in female evaluation of mean song amplitude and
amplitude maxima. We then consider the possibility that the variation observed in the
male population is a response to female choice, but we also indicate that mechanical
factors constraining song production may be responsible for such variation.
Top
Insect Learning
41. Interspecific and intersexual learning rate differences in four butterfly
species
Ikuo Kandori1,*, Takafumi Yamaki1, Sei-ichi Okuyama2, Noboru Sakamoto2 and Tomoyuki Yokoi3,
[email protected]
1
Laboratory of Entomology, Faculty of Agriculture, Kinki University, Japan
2
Itami City Museum of Insects, Japan
3
Laboratory of Insect Ecology, Graduate School of Agriculture, Kyoto University, Japan
Learning plays an important role in food acquisition for a wide range of insects and has
been demonstrated to be essential during flower foraging in taxa such as bees, parasitoid
wasps, butterflies and moths. However, little attention has been focused on differences in
floral cue learning abilities among species and sexes. We examined the associative
learning of flower colour with nectar in four butterfly species: Idea leuconoe, Argyreus
hyperbius, Pieris rapae and Lycaena phlaeas. All butterflies that were trained learned the
flower colours associated with food. The flower colour learning rates were significantly
higher in I. leuconoe and A. hyperbius than in P. rapae and L. phlaeas. Among the four
species examined, the larger and longer-lived species exhibited higher learning rates.
Furthermore, female butterflies showed a significantly higher learning rate than males.
This study provides the first evidence that learning abilities related to floral cues differ
among butterfly species. The adaptive significance of superior learning abilities in the
larger and longer-lived butterfly species and in females is discussed.
42. Thermal learning in the honeybee, Apis mellifera
Tobin J. Hammer, Curtis Hata and James C. Nieh* [email protected]
University of California San Diego, Division of Biological Sciences, Section of Ecology, Behavior, and
Evolution, Mail Code 01169500 Gilman Drive, La Jolla, CA 92093-0116, USA
Honeybee foragers are exposed to thermal stimuli when collecting food outside and
receiving food rewards inside the nest. In both contexts, there is an opportunity for
foragers to associate warmth with food rewards. However, honeybee thermal learning is
poorly understood. Using an associative learning paradigm (the proboscis extension
reflex), we show that honeybees can learn to associate a nectar reward with a heated
stimulus applied to the antenna to mimic natural contact with a warm flower or nectaroffering forager. Conditioning with longer inter-trial intervals (ITI) significantly improved
learning acquisition. We also trained bees to discriminate between temperatures above
(warm) and below (cold) ambient air temperature. Learning acquisition improved by 38%
per 10°C increase in absolute stimulus intensity (difference between the rewarded
temperature and unrewarded ambient air temperature). However, bees learned positive
temperature (warm) significantly better than negative temperature (cold) differences,
approximately twice as well for 10°C as compared with a –10°C difference. Thus,
thermosensation, a sensory modality that is relatively unexplored in honeybees, could
play a role in the acquisition of information from nestmates (social learning) and in
26
foraging decisions influenced by associations between floral temperature and nectar
rewards.
43. Structural and proteomic analyses reveal regional brain differences
during honeybee aging
F. Wolschin1,2,*, , D. Münch1,* and G. V. Amdam1,2 [email protected]
1
Department of Chemistry, Biotechnology and Food Science, University of Life Sciences, N-1432 Ås,
Norway
2
School of Life Sciences, Arizona State University, 85287 Tempe, USA
Among insects, learning is particularly well studied in the fruit fly Drosophila
melanogaster and the honeybee Apis mellifera. A senescence-dependent decline in classic
pavlovian conditioning is demonstrated for both species. To understand how aging affects
learning, genetic approaches used with Drosophila can benefit from complementary
studies in Apis. Specifically, honeybees have a larger brain size allowing for
compartment-specific approaches, and a unique life-history plasticity. They usually
perform within-nest tasks early in life (nest bees) and later they collect food (foragers).
Senescence of learning performance is a function of the bees' foraging duration but
underlying causes are poorly understood. As cognitive aging is commonly associated with
structural and biochemical changes in the brain, we hypothesized that brain areas
implicated in learning change in synaptic and biochemical composition with increased
foraging duration. First, we used synapse-specific immunohistochemistry and proteomics
to screen for alterations in the calyx region of the mushroom body, a key structure for
memory formation. Using proteomics, we next profiled the central brain, which comprises
all higher-order integration centers. We show that, with increased foraging duration,
levels of kinases, synaptic- and neuronal growth-related proteins decline in the central
brain while the calyx region remains intact both in structure and biochemistry. We
suggest that proteome-level changes within major anatomical sites of memory formation
other than the calyx region could be central to learning dysfunction. These include large
compartments of the central brain, such as the mushroom body's output regions and the
antennal lobes. Our data provide novel information toward heterogeneity in the aging
insect brain, and demonstrate advantages of the honeybee for invertebrate
neurogerontological research.
http://jeb.biologists.org/cgi/content/abstract/212/24/4027
44.Olfactory conditioning of the sting extension reflex in honeybees: Memory
dependence on trial number, interstimulus interval, intertrial interval,
and protein synthesis
Martin Giurfa1,2,4, Eve Fabre1,2,3, Justin Flaven-Pouchon1,2,3, Helga Groll1,2,3, Barbara
Oberwallner1,2,3, Vanina Vergoz1,2,3, Edith Roussel1,2 and Jean Christophe Sandoz1,2 [email protected]
1. Université de Toulouse, UPS, Centre de Recherches sur la Cognition Animale, F-31062 Toulouse
Cedex 9, France;
2. CNRS, Centre de Recherches sur la Cognition Animale, F-31062 Toulouse Cedex 9, France
Harnessed bees learn to associate an odorant with an electric shock so that afterward the
odorant alone elicits the sting extension response (SER). We studied the dependency of
retention on interstimulus interval (ISI), intertrial interval (ITI), and number of
conditioning trials in the framework of olfactory SER conditioning. Forward ISIs
(conditioned stimulus [CS] before unconditioned stimulus [US]) supported higher
retention than a backward one (US before CS) with an optimum around 3 sec. Spaced
trials (ITI 10 min) supported higher retention than massed trials (ITI 1 min) and led to
27
the formation of a late long-term memory (l-LTM) that depended on protein synthesis.
Our results reaffirm olfactory SER conditioning as a reliable tool for the study of learning
and memory.
Learn. Mem. 2009. 16: 761-765
http://learnmem.cshlp.org/content/16/12/761.abstract
45.Social learning about egg-laying substrates in fruitflies
Sachin Sarin and Reuven Dukas* [email protected]
Animal Behaviour Group, Department of Psychology, Neuroscience and Behaviour, McMaster University,
1280 Main Street West, Hamilton, ON L8S 4K1, Canada
Social learning, defined as learning from other individuals, has had dramatic effects on
some species, including humans, in whom it has generated a rich culture. As a first step
in examining the evolution of and mechanisms underlying social learning in insects, we
tested for social learning in fruitflies (Drosophila melanogaster). Focal females (observers)
that experienced novel food together with mated females (models), who had laid eggs on
that food, subsequently exhibited a stronger preference for laying eggs on that food over
another novel food compared with focal females that experienced the food alone. We
observed no social learning, however, when observers experienced food with potentially
more ambiguous social information provided by the presence of either virgin models or
aggregation pheromone. This first documentation of social learning about egg-laying
substrates in fruitflies builds on recent data indicating intricate use of social information
by fruitflies and opens up exciting avenues for research on the evolution and
neurogenetics of social learning using biology's major model system.
Top
Insect Metamorphosis
46.MicroRNA-dependent metamorphosis in hemimetabolan insects
Eva Gomez-Orte and Xavier Belles1 [email protected]
Institut de Biologia Evolutiva (Consejo Superior de Investigaciones Científicas and Universitat Pompeu
Fabra), Passeig Marítim de la Barceloneta, 37-49, 08003 Barcelona, Spain
How does a juvenile insect transform into an adult? This question, which sums up the
wonder of insect metamorphosis, has fascinated mankind since ancient times. Modern
physiology has established the endocrine basis regulating these transformations, which
mainly depend on two hormone types: ecdysteroids, which promote molts, and juvenile
hormones, which repress the transformation into the adult stage. The interplay of these
two hormones regulates the genes involved in juvenile and adult programs and the shift
from one to the other. microRNAs (miRNAs) are small noncoding RNAs, which participate
in many biological processes, and we wondered whether they might be also involved in
insect metamorphosis. In insects, Dicer-1 ribonuclease transforms miRNA precursors into
mature miRNAs. Thus, using systemic RNA interference (RNAi) to silence the expression
of Dicer-1 in the hemimetabolan insect Blattella germanica, we depleted miRNA contents
in the last instar nymph. This practically inhibited metamorphosis after the next molt, as
the resulting specimens showed nymphoid features and were able to molt again. The
experiments show that miRNAs play a key role in hemimetabolan metamorphosis,
perhaps regulating genes that are juvenile hormone targets.
28
47.The Insect Neuropeptide PTTH Activates Receptor Tyrosine Kinase Torso
to Initiate Metamorphosis
Kim F. Rewitz,1 Naoki Yamanaka,1,2 Lawrence I. Gilbert,3 Michael B. O’Connor1,2,* [email protected]
1
Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN
55455, USA.
2
Howard Hughes Medical Institute, University of Minnesota, Minneapolis, MN 55455, USA.
3
Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA.
Holometabolous insects undergo complete metamorphosis to become sexually mature
adults. Metamorphosis is initiated by brain-derived prothoracicotropic hormone (PTTH),
which stimulates the production of the molting hormone ecdysone via an incompletely
defined signaling pathway. Here we demonstrate that Torso, a receptor tyrosine kinase
that regulates embryonic terminal cell fate in Drosophila, is the PTTH receptor. Trunk, the
embryonic Torso ligand, is related to PTTH, and ectopic expression of PTTH in the embryo
partially rescues trunk mutants. In larvae, torso is expressed specifically in the
prothoracic gland (PG), and its loss phenocopies the removal of PTTH. The activation of
Torso by PTTH stimulates extracellular signal–regulated kinase (ERK) phosphorylation,
and the loss of ERK in the PG phenocopies the loss of PTTH and Torso. We conclude that
PTTH initiates metamorphosis by activation of the Torso/ERK pathway.
Science 4 December 2009: Vol. 326. no. 5958, pp. 1403 – 1405
http://www.sciencemag.org/cgi/content/abstract/326/5958/1403?sa_campaign=Email/to
c/4-December-2009/10.1126/science.1176450
Top
Insect Molecular Biology
48.Functional involvement of Tudor and dPRMT5 in the piRNA processing
pathway in Drosophila germlines
Kazumichi M Nishida1,2, Tomoko N Okada1, Takeshi Kawamura3, Toutai Mituyama4, Yoshinori Kawamura1,2,
Sachi Inagaki1, Haidong Huang5, Dahua Chen5, Tatsuhiko Kodama3, Haruhiko Siomi1 and Mikiko C Siomi1,6
[email protected]
1. Department of Molecular Biology, Keio University School of Medicine, Tokyo, Japan
2. Institute of Health Biosciences, University of Tokushima, Tokushima, Japan
3. Research Center for Advanced Science and Technology, University of Tokyo, Tokyo, Japan
4. Computational Biology Research Center (CBRC), National Institute of Advanced Industrial Science
and Technology (AIST), Tokyo, Japan
5. Institute of Zoology Chinese Academy of Sciences, Beijing, People's Republic of China
6. JST, CREST, Saitama, Japan
In Drosophila, the PIWI proteins, Aubergine (Aub), AGO3, and Piwi are expressed in
germlines and function in silencing transposons by associating with PIWI-interacting
RNAs (piRNAs). Recent studies show that PIWI proteins contain symmetric dimethylarginines (sDMAs) and that dPRMT5/Capsuleen/DART5 is the modifying enzyme. Here,
we show that Tudor (Tud), one of Tud domain-containing proteins, associates with Aub
and AGO3, specifically through their sDMA modifications and that these three proteins
form heteromeric complexes. piRNA precursor-like molecules are detected in these
complexes. The expression levels of Aub and AGO3, along with their degree of sDMA
modification, were not changed by tud mutations. However, the population of
transposon-derived piRNAs associated with Aub and AGO3 was altered by tud mutations,
whereas the total amounts of small RNAs on Aub and AGO3 was increased. Loss of
dprmt5 did not change the stability of Aub, but impaired its association with Tud and
lowered piRNA association with Aub. Thus, in germline cells, piRNAs are qualitycontrolled by dPRMT5 that modifies PIWI proteins, in tight association with Tud.
The EMBO Journal (2009) 28, 3820 - 3831
29
49.Pretaporter, a Drosophila protein serving as a ligand for Draper in the
phagocytosis of apoptotic cells
Takayuki Kuraishi1,7, Yukiko Nakagawa2, Kaz Nagaosa2, Yumi Hashimoto1, Takashi Ishimoto2, Takeshi Moki2,
Yu Fujita1, Hiroshi Nakayama3, Naoshi Dohmae3, Akiko Shiratsuchi1,2,4, Naoko Yamamoto2, Koichi Ueda4,
Masamitsu Yamaguchi5, Takeshi Awasaki6 and Yoshinobu Nakanishi1,2,4 [email protected]
1. Graduate School of Medical Science, Kanazawa University, Kanazawa, Ishikawa, Japan
2. Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Ishikawa,
Japan
3. Biomolecule Characterization Team, RIKEN, Wako, Saitama, Japan
4. Faculty of Pharmaceutical Sciences, Kanazawa University, Kanazawa, Ishikawa, Japan
5. Department of Applied Biology, Kyoto Institute of Technology, Kyoto, Kyoto, Japan
6. Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA, USA
Phagocytic removal of cells undergoing apoptosis is necessary for animal development
and tissue homeostasis. Draper, a homologue of the Caenorhabditis elegans phagocytosis
receptor CED-1, is responsible for the phagocytosis of apoptotic cells in Drosophila, but
its ligand presumably present on apoptotic cells remains unknown. An endoplasmic
reticulum protein that binds to the extracellular region of Draper was isolated. Loss of
this protein, which we name Pretaporter, led to a reduced level of apoptotic cell clearance
in embryos, and the overexpression of pretaporter in the mutant flies rescued this defect.
Results from genetic analyses suggested that Pretaporter functionally interacts with
Draper and the corresponding signal mediators. Pretaporter was exposed at the cell
surface after the induction of apoptosis, and cells artificially expressing Pretaporter at
their surface became susceptible to Draper-mediated phagocytosis. Finally, the
incubation with Pretaporter augmented the tyrosine-phosphorylation of Draper in
phagocytic cells. These results collectively suggest that Pretaporter relocates from the
endoplasmic reticulum to the cell surface during apoptosis to serve as a ligand for Draper
in the phagocytosis of apoptotic cells.
The EMBO Journal (2009) 28, 3868 - 3878
50. Spatial distribution of opsin-encoding mRNAs in the tiered larval retinas
of the sunburst diving beetle Thermonectus marmoratus (Coleoptera:
Dytiscidae)
Srdjan Maksimovic1, Tiffany A. Cook2 and Elke K. Buschbeck1,* [email protected]
1
Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio 45221-0006, USA
2
Division of Developmental Biology and Department of Pediatric Ophthalmology, Cincinnati Children's
Hospital Medical Center, Cincinnati, Ohio 45229, USA
Larvae of the sunburst diving beetle, Thermonectus marmoratus, have a cluster of six
stemmata (E1-6) and one eye patch on each side of the head. Each eye has two retinas:
a distal retina that is closer to the lens, and a proximal retina that lies directly underneath.
The distal retinas of E1 and E2 are made of a dorsal and a ventral stack of at least twelve
photoreceptor layers. Could this arrangement be used to compensate for lens chromatic
aberration, with shorter wavelengths detected by the distal layers and longer
wavelengths by the proximal layers? To answer this question we molecularly identified
opsins and their expression patterns in these eyes. We found three opsin-encoding genes.
The distal retinas of all six eyes express long-wavelength opsin (TmLW) mRNA, whereas
the proximal retinas express ultraviolet opsin (TmUV I) mRNA. In the proximal retinas of
E1 and E2, the TmUV I mRNA is expressed only in the dorsal stack. A second ultraviolet
opsin mRNA (TmUV II), is expressed in the proximal retinas of E1 and E2 (both stacks).
The finding that longer-wavelength opsins are expressed distally to shorter-wavelength
opsins makes it unlikely that this retinal arrangement is used to compensate for lens
chromatic aberration. In addition, we also described opsin expression patterns in the
medial retina of E1 and in the non-tiered retina of the lensless eye patch. To our
30
knowledge, this is also the first report of multiple UV opsins being expressed in the same
stemma.
51.The Drosophila DHR96 nuclear receptor binds cholesterol and regulates
cholesterol homeostasis
Michael A. Horner1, Keith Pardee2, Suya Liu3, Kirst King-Jones4, Gilles Lajoie3, Aled Edwards2, Henry
M. Krause2 and Carl S. Thummel1,
1
Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah 84112,
USA;
2
Banting and Best Department of Medical Research, University of Toronto, Toronto Ontario M5G 1L6,
Canada;
3
UWO Biological Mass Spectrometry Laboratory, University of Western Ontario, London, Ontario N6G
2V4, Canada;
4
Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
Cholesterol homeostasis is required to maintain normal cellular function and avoid the
deleterious effects of hypercholesterolemia. Here we show that the Drosophila DHR96
nuclear receptor binds cholesterol and is required for the coordinate transcriptional
response of genes that are regulated by cholesterol and involved in cholesterol uptake,
trafficking, and storage. DHR96 mutants die when grown on low levels of cholesterol and
accumulate excess cholesterol when maintained on a high-cholesterol diet. The
cholesterol accumulation phenotype can be attributed to misregulation of npc1b, an
ortholog of the mammalian Niemann-Pick C1-like 1 gene NPC1L1, which is essential for
dietary cholesterol uptake. These studies define DHR96 as a central regulator of
cholesterol homeostasis.
Genes & Dev. 2009. 23: 2711-2716
http://genesdev.cshlp.org/content/23/23/2711.abstract
52.A novel histone fold domain-containing protein that replaces TAF6 in
Drosophila SAGA is required for SAGA-dependent gene expression
Vikki M. Weake1, Selene K. Swanson1, Arcady Mushegian1,2, Laurence Florens1, Michael P.
Washburn1,3, Susan M. Abmayr1,4 and Jerry L. Workman1,[email protected]
1
Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA;
2
Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center,
Kansas City, Kansas 66160, USA;
3
Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City,
Kansas 66160, USA;
4
Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, Kansas
66160, USA
The histone acetyltransferase complex SAGA is well characterized as a coactivator
complex in yeast. In this study of Drosophila SAGA (dSAGA), we describe three novel
components that include an ortholog of Spt20, a potential ortholog of Sgf73/ATXN7, and
a novel histone fold protein, SAF6 (SAGA factor-like TAF6). SAF6, which binds directly to
TAF9, functions analogously in dSAGA to TAF6/TAF6L in the yeast and human SAGA
complexes, respectively. Moreover, TAF6 in flies is restricted to TFIID. Mutations in saf6
disrupt SAGA-regulated gene expression without disrupting acetylated or ubiquitinated
histone levels. Thus, SAF6 is essential for SAGA coactivator function independent of the
enzymatic activities of the complex.
Genes & Dev. 2009. 23: 2818-2823
http://genesdev.cshlp.org/content/23/24/2818.abstract?etoc
31
Top
Insect Neuroethology
53.Local and global motion preferences in descending neurons of the fly
Adrian Wertz1 , Juergen Haag1 and Alexander Borst1 [email protected]
1 Department of Systems and Computational Neurobiology, Max-Planck-Institute of Neurobiology, Am
Klopferspitz 18, 82152 Martinsried, Germany
For a moving animal, optic flow is an important source of information about its egomotion. In flies, the processing of optic flow is performed by motion sensitive tangential
cells in the lobula plate. Amongst them, cells of the vertical system (VS cells) have
receptive fields with similarities to optic flows generated during rotations around different
body axes. Their output signals are further processed by pre-motor descending neurons.
Here, we investigate the local motion preferences of two descending neurons called
descending neurons of the ocellar and vertical system (DNOVS1 and DNOVS2). Using an
LED arena subtending 240° × 95° of visual space, we mapped the receptive fields of
DNOVS1 and DNOVS2 as well as those of their presynaptic elements, i.e. VS cells 1–10
and V2. The receptive field of DNOVS1 can be predicted in detail from the receptive fields
of those VS cells that are most strongly coupled to the cell. The receptive field of
DNOVS2 is a combination of V2 and VS cells receptive fields. Predicting the global motion
preferences from the receptive field revealed a linear spatial integration in DNOVS1 and a
superlinear spatial integration in DNOVS2. In addition, the superlinear integration of V2
output is necessary for DNOVS2 to differentiate between a roll rotation and a lift
translation of the fly.
Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral
Physiology Volume 195, Number 12 / December, 2009 1107-1120
http://www.springerlink.com/content/7p871645856140ul/
54.A descending contralateral directionally selective movement detector in
the praying mantis Tenodera aridifolia
Yoshifumi Yamawaki1 and Yoshihiro Toh1 [email protected]
1 Department of Biology, Faculty of Science, Kyushu University, Fukuoka 812-8581, Japan
Extracellular recordings were made from a directionally selective neuron in the ventral
nerve cord of mantises. The neuron’s preferred direction of motion was forward and
upward over the compound eye contralateral to its axon at the cervical connective. The
neuron was sensitive to wide-field motion stimuli, resistant to habituation, and showed
transient excitation in response to light ON and OFF stimuli. Its responses to drifting
gratings depended on the temporal frequency and contrast of the stimulus. These results
suggest that the neuron receives input from correlation-type motion detectors.
http://www.springerlink.com/content/t4v72x575n5u7607/
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Insect Neuroscience
55.Ems and Nkx6 are central regulators in dorsoventral patterning of the
Drosophila brain
Janina Seibert, Dagmar Volland and Rolf Urbach*[email protected]
Institute of Genetics, University of Mainz,D-55099 Mainz, Germany
32
In central nervous system development, the identity of neural stem cells (neuroblasts)
critically depends on the precise spatial patterning of the neuroectoderm in the
dorsoventral (DV) axis. Here, we uncover a novel gene regulatory network underlying DV
patterning in the Drosophila brain, and show that the cephalic gap gene empty spiracles
(ems) and the Nk6 homeobox gene (Nkx6) encode key regulators. The regulatory
network implicates novel interactions between these and the evolutionarily conserved
homeobox genes ventral nervous system defective (vnd), intermediate neuroblasts
defective (ind) and muscle segment homeobox (msh). We show that Msh crossrepressively interacts with Nkx6 to sustain the boundary between dorsal and
intermediate neuroectoderm in the tritocerebrum (TC) and deutocerebrum (DC), and that
Vnd positively regulates Nkx6 by suppressing Msh. Remarkably, Ems is required to
activate Nkx6, ind and msh in the TC and DC, whereas later Nkx6 and Ind act together to
repress ems in the intermediate DC. Furthermore, the initially overlapping expression of
Ems and Vnd in the ventral/intermediate TC and DC resolves into complementary
expression patterns due to cross-repressive interaction. These results indicate that the
anteroposterior patterning gene ems controls the expression of DV genes, and vice versa.
In addition, in contrast to regulation in the ventral nerve cord, cross-inhibition between
homeodomain factors (between Ems and Vnd, and between Nkx6 and Msh) is essential
for the establishment and maintenance of discrete DV gene expression domains in the
Drosophila brain. This resembles the mutually repressive relationship between pairs of
homeodomain proteins that pattern the vertebrate neural tube in the DV axis.
56.The target of rapamycin complex 2 controls dendritic tiling of Drosophila
sensory neurons through the Tricornered kinase signalling pathway
Makiko Koike-Kumagai1, Kei-ichiro Yasunaga1, Rei Morikawa1, Takahiro Kanamori1 and Kazuo Emoto1,2,3
[email protected]
1. Neural Morphogenesis Laboratory, National Institute of Genetics, Mishima, Japan
2. Department of Genetics, SOKENDAI, Mishima, Japan
3. PRESTO, Japan Science and Technology Agency, Saitama, Japan
To cover the receptive field completely and non-redundantly, neurons of certain
functional groups arrange tiling of their dendrites. In Drosophila class IV dendrite
arborization (da) neurons, the NDR family kinase Tricornered (Trc) is required for
homotypic repulsion of dendrites that facilitates dendritic tiling. We here report that Sin1,
Rictor, and target of rapamycin (TOR), components of the TOR complex 2 (TORC2), are
required for dendritic tiling of class IV da neurons. Similar to trc mutants, dendrites of
sin1 and rictor mutants show inappropriate overlap of the dendritic fields. TORC2
components physically and genetically interact with Trc, consistent with a shared role in
regulating dendritic tiling. Moreover, TORC2 is essential for Trc phosphorylation on a
residue that is critical for Trc activity in vivo and in vitro. Remarkably, neuronal
expression of a dominant active form of Trc rescues the tiling defects in sin1 and rictor
mutants. These findings suggest that TORC2 likely acts together with the Trc signalling
pathway to regulate the dendritic tiling of class IV da neurons, and thus uncover the first
neuronal function of TORC2 in vivo.
The EMBO Journal (2009) 28, 3879 - 3892
57.Imaging neural activity in worms, flies and mice with improved GCaMP
calcium indicators
Lin Tian1, S Andrew Hires1, Tianyi Mao1, Daniel Huber1, M Eugenia Chiappe1, Sreekanth H Chalasani2,
Leopoldo Petreanu1, Jasper Akerboom1, Sean A McKinney1,4, Eric R Schreiter3, Cornelia I Bargmann2, Vivek
Jayaraman1, Karel Svoboda1 & Loren L Looger1 [email protected]
33
1.
2.
3.
4.
Howard Hughes Medical Institute, Janelia Farm Research Campus, Ashburn, Virginia, USA.
Howard Hughes Medical Institute, Laboratory of Neural Circuits and Behavior, The Rockefeller
University, New York, New York, USA.
Department of Chemistry, University of Puerto Rico, Río Piedras, San Juan, Puerto Rico.
Present address: The Stowers Institute, Kansas City, Missouri, USA.
Genetically encoded calcium indicators (GECIs) can be used to image activity in defined
neuronal populations. However, current GECIs produce inferior signals compared to
synthetic indicators and recording electrodes, precluding detection of low firing rates. We
developed a single-wavelength GCaMP2-based GECI (GCaMP3), with increased baseline
fluorescence (3-fold), increased dynamic range (3-fold) and higher affinity for calcium
(1.3-fold). We detected GCaMP3 fluorescence changes triggered by single action
potentials in pyramidal cell dendrites, with signal-to-noise ratio and photostability
substantially better than those of GCaMP2, D3cpVenus and TN-XXL. In Caenorhabditis
elegans chemosensory neurons and the Drosophila melanogaster antennal lobe, sensory
stimulation–evoked fluorescence responses were significantly enhanced with GCaMP3 (4–
6-fold). In somatosensory and motor cortical neurons in the intact mouse, GCaMP3
detected calcium transients with amplitudes linearly dependent on action potential
number. Long-term imaging in the motor cortex of behaving mice revealed large
fluorescence changes in imaged neurons over months.
Nature Methods 6, 875 - 881 (2009) Published online: 8 November 2009
http://www.nature.com/nmeth/journal/v6/n12/abs/nmeth.1398.html?lang=en
58.Leucine-rich repeat transmembrane proteins instruct discrete dendrite
targeting in an olfactory map
Weizhe Hong1, Haitao Zhu1,4, Christopher J Potter1, Gabrielle Barsh1, Mitsuhiko Kurusu2,3, Kai Zinn2 & Liqun
Luo1 [email protected]
1.
2.
3.
4.
Howard Hughes Medical Institute and Department of Biology, Stanford University, Stanford,
California, USA.
Division of Biology, California Institute of Technology, Pasadena, California, USA.
Structural Biology Center, National Institute of Genetics, and Department of Genetics, the
Graduate University for Advanced Studies, Mishima, Japan.
Present address: Department of Neurodegeneration, Genentech, South San Francisco, California,
USA.
Olfactory systems utilize discrete neural pathways to process and integrate odorant
information. In Drosophila, axons of first-order olfactory receptor neurons (ORNs) and
dendrites of second-order projection neurons (PNs) form class-specific synaptic
connections at 50 glomeruli. The mechanisms underlying PN dendrite targeting to
distinct glomeruli in a three-dimensional discrete neural map are unclear. We found that
the leucine-rich repeat (LRR) transmembrane protein Capricious (Caps) was differentially
expressed in different classes of PNs. Loss-of-function and gain-of-function studies
indicated that Caps instructs the segregation of Caps-positive and Caps-negative PN
dendrites to discrete glomerular targets. Moreover, Caps-mediated PN dendrite targeting
was independent of presynaptic ORNs and did not involve homophilic interactions. The
closely related protein Tartan was partially redundant with Caps. These LRR proteins are
probably part of a combinatorial cell-surface code that instructs discrete olfactory map
formation.
Nature Neuroscience 12, 1542 - 1550 (2009) Published online: 15 November 2009
http://www.nature.com/neuro/journal/v12/n12/abs/nn.2442.html?lang=en
59.Frequency Transitions in Odor-Evoked Neural Oscillations
Iori Ito1, Maxim Bazhenov2, Rose Chik-ying Ong1, 3, Baranidharan Raman1, 4 and Mark Stopfer1,
1
National Institute of Child Health and Human Development, National Institutes of Health, Bethesda,
MD 20892, USA
34
2
Department of Cell Biology and Neuroscience, University of California, Riverside, CA 92521, USA
3
Department of Biochemistry, The Chinese University of Hong Kong, Hong Kong
4
Chemical Science and Technology Laboratory, National Institute of Standards and Technology, 100
Bureau Drive, Stop 8362, Gaithersburg, MD 20899-8362, USA
In many species, sensory stimuli elicit the oscillatory synchronization of groups of
neurons. What determines the properties of these oscillations? In the olfactory system of
the moth, we found that odors elicited oscillatory synchronization through a neural
mechanism like that described in locust and Drosophila. During responses to long odor
pulses, oscillations suddenly slowed as net olfactory receptor neuron (ORN) output
decreased; thus, stimulus intensity appeared to determine oscillation frequency. However,
changing the concentration of the odor had little effect upon oscillatory frequency. Our
recordings in vivo and computational models based on these results suggested that the
main effect of increasing odor concentration was to recruit additional, less well-tuned
ORNs whose firing rates were tightly constrained by adaptation and saturation. Thus, in
the periphery, concentration is encoded mainly by the size of the responsive ORN
population, and oscillation frequency is set by the adaptation and saturation of this
response.
Neuron, Volume 64, Issue 5, 692-706, 10 December 2009
http://www.cell.com/neuron/abstract/S0896-6273%2809%2900805-8
60.Glycogen synthase kinase-3/Shaggy mediates ethanol-induced
excitotoxic cell death of Drosophila olfactory neurons
Rachael L. French1 and Ulrike Heberlein1
Department of Anatomy and Program in Neuroscience, University of California at San Francisco, 1550
4th Street, San Francisco, CA 94143-2324
It has long been known that heavy alcohol consumption leads to neuropathology and
neuronal death. While the response of neurons to an ethanol insult is strongly influenced
by genetic background, the underlying mechanisms are poorly understood. Here, we
show that even a single intoxicating exposure to ethanol causes non-cell-autonomous
apoptotic death specifically of Drosophila olfactory neurons, which is accompanied by a
loss of a behavioral response to the smell of ethanol and a blackening of the third
antennal segment. The Drosophila homolog of glycogen synthase kinase-3 (GSK-3)β,
Shaggy, is required for ethanol-induced apoptosis. Consistent with this requirement, the
GSK-3β inhibitor lithium protects against the neurotoxic effects of ethanol, indicating the
possibility for pharmacological intervention in cases of alcohol-induced
neurodegeneration. Ethanol-induced death of olfactory neurons requires both their neural
activity and functional NMDA receptors. This system will allow the investigation of the
genetic and molecular basis of ethanol-induced apoptosis in general and provide an
understanding of the molecular role of GSK-3β in programmed cell death.
http://www.pnas.org/content/106/49/20924.abstract
61.Peripheral modulation of worker bee responses to queen mandibular
pheromone
Vanina Vergoz1, H. James McQuillan1, Lisa H. Geddes, Kiri Pullar, Brad J. Nicholson, Michael G. Paulin
and Alison R. Mercer1 [email protected]
Department of Zoology, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand
It is generally accepted that young worker bees (Apis mellifera L.) are highly attracted to
queen mandibular pheromone (QMP). Our results challenge this widely held view. We
have found that unless young workers are exposed to QMP early in adult life, they, like
foragers, avoid contact with this pheromone. Our data indicate that responses to QMP
are regulated peripherally, at the level of the antennal sensory neurons, and that a
35
window of opportunity exists in which QMP can alter a young bee's response to this
critically important pheromone. Exposing young bees to QMP from the time of adult
emergence reduces expression in the antennae of the D1-like dopamine receptor gene,
Amdop1. Levels of Amdop3 transcript, on the other hand, and of the octopamine receptor
gene Amoa1, are significantly higher in the antennae of bees strongly attracted to QMP
than in bees showing no attraction to this pheromone. A decline in QMP attraction with
age is accompanied by a fall in expression in worker antennae of the D2-like dopamine
receptor, AmDOP3, a receptor that is selectively activated by QMP. Taken together, our
findings suggest that QMP's actions peripherally not only suppress avoidance behavior,
but also enhance attraction to QMP, thereby facilitating attendance of the queen.
http://www.pnas.org/content/106/49/20930.abstract
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Insect Nutrition
62.Amino-acid imbalance explains extension of lifespan by dietary restriction
in Drosophila
Richard C. Grandison1,2, Matthew D. W. Piper1,2 & Linda Partridge1 [email protected]
Institute of Healthy Ageing, Department of Genetics Evolution and Environment, University College
London, Gower St, London WC1E 6BT, UK
Dietary restriction extends healthy lifespan in diverse organisms and reduces fecundity1, 2.
It is widely assumed to induce adaptive reallocation of nutrients from reproduction to
somatic maintenance, aiding survival of food shortages in nature3, 4, 5, 6. If this were the
case, long life under dietary restriction and high fecundity under full feeding would be
mutually exclusive, through competition for the same limiting nutrients. Here we report a
test of this idea in which we identified the nutrients producing the responses of lifespan
and fecundity to dietary restriction in Drosophila. Adding essential amino acids to the
dietary restriction condition increased fecundity and decreased lifespan, similar to the
effects of full feeding, with other nutrients having little or no effect. However, methionine
alone was necessary and sufficient to increase fecundity as much as did full feeding, but
without reducing lifespan. Reallocation of nutrients therefore does not explain the
responses to dietary restriction. Lifespan was decreased by the addition of amino acids,
with an interaction between methionine and other essential amino acids having a key role.
Hence, an imbalance in dietary amino acids away from the ratio optimal for reproduction
shortens lifespan during full feeding and limits fecundity during dietary restriction.
Reduced activity of the insulin/insulin-like growth factor signalling pathway extends
lifespan in diverse organisms7, and we find that it also protects against the shortening of
lifespan with full feeding. In other organisms, including mammals, it may be possible to
obtain the benefits to lifespan of dietary restriction without incurring a reduction in
fecundity, through a suitable balance of nutrients in the diet.
Nature 462, 1061-1064 (24 December 2009)
http://www.nature.com/nature/journal/v462/n7276/abs/nature08619.html?lang=en
Top
Insect Pharmacology
63.Transduction mechanism(s) of Na-saccharin in the blowfly Protophormia
terraenovae: evidence for potassium and calcium conductance
involvement
Carla Masala1, Paolo Solari1, Giorgia Sollai1, Roberto Crnjar1 and Anna Liscia1 [email protected]
36
1 Department of Experimental Biology, Section of General Physiology, University of Cagliari, Cittadella
Universitaria di Monserrato, SS 554, Km 4.500, 09042 Monserrato, CA, Italy
The study on transduction mechanisms underlying bitter stimuli is a particularly
intriguing challenge for taste researchers. The present study investigates, in the labellar
chemosensilla of the blowfly Protophormia terraenovae, the transduction mechanism by
which saccharin evokes the response of the “deterrent” cell, with particular attention to
the contribution of K+ and Ca2+ current and the role of cyclic nucleotides, since second
messengers modulate Ca2+, Cl− and K+ currents to different extents. As assessed by
extracellular single-sensillum recordings, our results show that the addition of a Ca2+
chelator such as EGTA or the Ca2+ current blockers SK&F-96365, Mibefradil, Nifedipine
and W-7 decrease the response of the “deterrent” cell to saccharin. A similar decreasing
effect was also obtained following the addition of 4-aminopyridine, a K+ current blocker.
On the contrary, the membrane-permeable cyclic nucleotide 8-bromoguanosine 3′,5′cyclic monophosphate (8Br-cGMP) activates this cell and shows an additive effect when
presented mixed with saccharin. Our results are consistent with the hypothesis that in
the labellar chemosensilla of the blowfly both Ca2+ and K+ ions are involved in the
transduction mechanism of the “deterrent” cell in response to saccharin. Our results also
suggest a possible pathway common to saccharin and 8Br-cGMP.
http://www.springerlink.com/content/e423tu0uj7605u5u/
Top
Insect Photoreception
64.Specialized ommatidia of the polarization-sensitive dorsal rim area in the
eye of monarch butterflies have non-functional reflecting tapeta
Thomas Labhart1 , Franziska Baumann1 and Gary D. [email protected]
1 Institute of Zoology, University of Zurich, Winterthurerstrasse 190, CH 8057 Zurich, Switzerland
2 Department of Electrical Engineering, University of Washington, Seattle, WA 98195-2500, USA
Many insects exploit sky light polarization for navigation or cruising-course control. The
detection of polarized sky light is mediated by the ommatidia of a small specialized part
of the compound eye: the dorsal rim area (DRA). We describe the morphology and fine
structure of the DRA in monarch butterflies (Danaus plexippus). The DRA consists of
approximately 100 ommatidia forming a narrow ribbon along the dorsal eye margin. Each
ommatidium contains two types of photoreceptor with mutually orthogonal microvilli
orientations occurring in a 2:6 ratio. Within each rhabdomere, the microvilli are well
aligned. Rhabdom structure and orientation remain constant at all retinal levels, but the
rhabdom profiles, as seen in tangential sections through the DRA, change their
orientations in a fan-like fashion from the frontal to the caudal end of the DRA. Whereas
these properties (two microvillar orientations per rhabdom, microvillar alignment along
rhabdomeres, ommatidial fan array) are typical for insect DRAs in general, we also report
and discuss here a novel feature. The ommatidia of monarch butterflies are equipped
with reflecting tapeta, which are directly connected to the proximal ends of the rhabdoms.
Although tapeta are also present in the DRA, they are separated from the rhabdoms by a
space of approximately 55 μm effectively inactivating them. This reduces self-screening
effects, keeping polarization sensitivity of all photoreceptors of the DRA ommatidia both
high and approximately equal.
http://www.springerlink.com/content/h613q35p24540641/
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Insect Physiology
65. Isoform- and cell-specific function of tyrosine decarboxylase in the
Drosophila Malpighian tubule
Edward M. Blumenthal [email protected]
Department of Biological Sciences, Marquette University, P.O. Box 1881, Milwaukee, WI 53201-1881,
USA
The biogenic amine tyramine (TA) is a potent diuretic factor when applied to the
Malpighian tubule (MT) of Drosophila melanogaster, stimulating both urine production
and transepithelial chloride conductance. Isolated MTs can respond not only to TA but
also to its precursor, tyrosine; this observation led to the proposal that MTs are able to
synthesize TA from applied tyrosine through the action of the enzyme tyrosine
decarboxylase (TDC). In the current study it is shown that the non-neuronal isoform of
TDC, Tdc1, is expressed in the principal cells of the MT. A mutant allele of Tdc1, Tdc1f03311,
was identified that reduced expression of the mature Tdc1 transcript by greater than
100-fold. MTs isolated from Tdc1f03311 homozygous flies showed no significant
depolarization of their transepithelial potential (TEP) or diuresis in response to tyrosine
while retaining normal sensitivity to TA. By contrast, a previously identified null mutant
allele of the neuronal TDC isoform Tdc2 had no effect on either tyrosine or TA sensitivity.
To determine in which cell type of the MT Tdc1 expression is required, flies were
generated carrying a UAS-Tdc1 transgene and cell-type-specific Gal4 drivers on a
Tdc1f03311 homozygous background. Rescue of Tdc1 expression in principal cells fully
restored sensitivity to tyrosine whereas expression of Tdc1 in stellate cells had no
rescuing effect. It is concluded that synthesis of TA by Tdc1 in the principal cells of the
MT is required for physiological responses to tyrosine. TA synthesis in the MT is the first
reported physiological role for Drosophila Tdc1.
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Insect Sex Determination
66.The origin of a selfish B chromosome triggering paternal sex ratio in the
parasitoid wasp Trichogramma kaykai
Joke J. F. A. Van Vugt1,†Hans de Jong2 and Richard Stouthamer3,* [email protected]
1. Laboratory of Entomology, Wageningen University, PO Box 8031, 6700 EH Wageningen, The
Netherlands
2. Laboratory of Genetics, Wageningen University, Arboretumlaan 4, 6703 BD Wageningen, The
Netherlands
3. Department of Entomology, University of California, Riverside, CA 92521, USA
This study uses molecular and cytogenetic methods to determine the origin of a B
chromosome in some males of the wasp Trichogramma kaykai. This so-called paternal
sex ratio (PSR) chromosome transmits only through sperm and shortly after fertilization
triggers degeneration of the paternal genome, while keeping itself intact. The resulting
embryos develop into haploid B-chromosome-carrying males. Another PSR chromosome
with a very similar mode of action is found in the distantly related wasp Nasonia
vitripennis and its origin was traced by transposon similarity to the genus Trichomalopsis,
which is closely related to Nasonia. To determine whether both PSR chromosomes have a
similar origin we aimed to reveal the origin of the Trichogramma PSR chromosome. Using
fluorescent in situ hybridization, we discovered a major satellite repeat on the PSR
chromosome, the 45S ribosomal DNA. Analysis of the internal transcribed spacer 2 (ITS2)
of this repeat showed the presence of multiple ITS2 sequences on the PSR chromosome
38
resembling either the ITS2 of T. oleae or of T. kaykai. We therefore conclude that the
Trichogramma PSR chromosome originates from T. oleae or a T. oleae-like species. Our
results are consistent with different origins for the PSR chromosomes in Trichogramma
and Nasonia.
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Insect Society
67. Brood pheromone suppresses physiology of extreme longevity in
honeybees (Apis mellifera)
B. Smedal1, M. Brynem2, C. D. Kreibich1 and G. V. Amdam1,3,* [email protected]
1
Department of Chemistry, Biotechnology and Food Science, University of Life Sciences, P.O. Box
5003, N-1432 Aas, Norway
2
Department of Animal and Aquacultural Sciences, University of Life Sciences, P.O. Box 5003, N-1432
Aas, Norway
3
School of Life Science, Arizona State University, Tempe, P.O. Box 874501, AZ 85287, USA.
Honeybee (Apis mellifera) society is characterized by a helper caste of essentially sterile
female bees called workers. Workers show striking changes in lifespan that correlate with
changes in colony demography. When rearing sibling sisters (brood), workers survive for
3-6 weeks. When brood rearing declines, worker lifespan is 20 weeks or longer. Insects
can survive unfavorable periods on endogenous stores of protein and lipid. The glycolipoprotein vitellogenin extends worker bee lifespan by functioning in free radical defense,
immunity and behavioral control. Workers use vitellogenin in brood food synthesis, and
the metabolic cost of brood rearing (nurse load) may consume vitellogenin stores and
reduce worker longevity. Yet, in addition to consuming resources, brood secretes a
primer pheromone that affects worker physiology and behavior. Odors and odor
perception can influence invertebrate longevity but it is unknown whether brood
pheromone modulates vitellogenin stores and survival. We address this question with a 2factorial experiment where 12 colonies are exposed to combinations of absence vs
presence of brood and brood pheromone. Over an age-course of 24 days, we monitor the
amount of vitellogenin stored in workers' fat body (adipose tissue). Thereafter, we track
colony survival for 200 days. We demonstrate that brood rearing reduces worker
vitellogenin stores and colony long-term survival. Yet also, we establish that the effects
can result solely from exposure to brood pheromone. These findings indicate that
molecular systems of extreme lifespan regulation are integrated with the sensory system
of honeybees to respond to variation in a primer pheromone secreted from larvae.
68.Flexible task allocation and the organization of work in ants
Elva J. H. Robinson1,*Ofer Feinerman2 and Nigel R. Franks1 [email protected]
School of Biological Sciences, University of Bristol, Woodland Road, Bristol BS8 1UG, UK
Computational Biology Center, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, Box 460,
New York, NY 10021, USA
Flexibility in task performance is essential for a robust system of division of labour. We
investigated what factors determine which social insect workers respond to colony-level
changes in task demand. We used radio-frequency identification technology to compare
the roles of corpulence, age, spatial location and previous activity (intra-nest/extra-nest)
in determining whether worker ants (Temnothorax albipennis) respond to an increase in
demand for foraging or brood care. The less corpulent ants took on the extra foraging,
39
irrespective of their age, previous activity or location in the nest, supporting a
physiological threshold model. We found no relationship between ants that tended the
extra brood and corpulence, age, spatial location or previous activity, but ants that
transported the extra brood to the main brood pile were less corpulent and had high
previous intra-nest activity. This supports spatial task-encounter and physiological
threshold models for brood transport. Our data suggest a flexible task-allocation system
allowing the colony to respond rapidly to changing needs, using a simple task-encounter
system for generalized tasks, combined with physiologically based response thresholds
for more specialized tasks. This could provide a social insect colony with a robust division
of labour, flexibly allocating the workforce in response to current needs.
69.Polymorphic social organization in an ant
Richard J. Gill1, Andres Arce1, Laurent Keller2 and Robert L. Hammond1,* [email protected]
1. Department of Biological Sciences, University of Hull, Cottingham Road, Hull HU6 7RX, UK
2. Department of Ecology and Evolution, Biophore, University of Lausanne, 1015 Lausanne,
Switzerland
Identifying species exhibiting variation in social organization is an important step towards
explaining the genetic and environmental factors underlying social evolution. In most
studied populations of the ant Leptothorax acervorum, reproduction is shared among
queens in multiple queen colonies (polygyny). By contrast, reports from other
populations, but based on weaker evidence, suggest a single queen may monopolize all
reproduction in multiple queen colonies (functional monogyny). Here we identify a
marked polymorphism in social organization in this species, by conclusively showing that
functional monogyny is exhibited in a Spanish population, showing that the social
organization is stable and not purely a consequence of daughter queens overwintering,
that daughter queen re-adoption is frequent and queen turnover is low. Importantly, we
show that polygynous and functionally monogynous populations are not genetically
distinct from one another based on mtDNA and nDNA. This suggests a recent
evolutionary divergence between social phenotypes. Finally, when functionally
monogynous and polygynous colonies were kept under identical laboratory conditions,
social organization did not change, suggesting a genetic basis for the polymorphism. We
discuss the implications of these findings to the study of reproductive skew.
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Insect Vision
70.Visual detection of diminutive floral guides in the bumblebee Bombus
terrestris and in the honeybee Apis mellifera
Klaus Lunau1 , Katrin Unseld1 and Franziska Wolter1 [email protected]
1 Sensory Ecology Group, Institute of Neurobiology, Heinrich-Heine-University, 40225 Düsseldorf,
Germany
Many flowers display colour patterns comprising a large peripheral colour area that
serves to attract flower visitors from some distance, and a small central, contrastingly
coloured area made up by stamens or floral guides. In this study, we scaled down the
size of floral guides to detect the minimal size bumblebees (Bombus terrestris) and
honeybees (Apis mellifera) require for guidance. We analyzed the approach and the
precise contact of the antennal tips with the floral guide of artificial flowers which
precedes landing and inspection. Both bumblebees and honeybees were able to make
40
antennal contact with circular floral guides which were 2 mm in diameter; bumblebees
performed better than honeybees and antennated also at floral guides smaller than 2 mm.
In discrimination experiments with bumblebees, a minimum floral guide size of 2 mm
was required for discrimination between artificial flowers with and without floral guides.
With increasing experience bumblebees targeted close to the site of reward instead of
making antennal contact with the floral guide, whereas honeybees did not alter their
initial behaviour with growing experience. Bumblebees and honeybees spontaneously
target diminutive floral guides to achieve physical contact with flowers by means of their
antennae which helps them to inspect flowers.
http://www.springerlink.com/content/tg2g7127654hjxn6/
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Insect Review
71.Are Bigger Brains Better?
Lars Chittka1, and Jeremy Niven2
1
Queen Mary University of London, Research Centre for Psychology, School of Biological and Chemical
Sciences, Mile End Road, London E1 4NS, UK
2
University of Cambridge, Department of Zoology, Downing Street, Cambridge CB2 3EJ, UK
Attempts to relate brain size to behaviour and cognition have rarely integrated
information from insects with that from vertebrates. Many insects, however, demonstrate
that highly differentiated motor repertoires, extensive social structures and cognition are
possible with very small brains, emphasising that we need to understand the neural
circuits, not just the size of brain regions, which underlie these feats. Neural network
analyses show that cognitive features found in insects, such as numerosity, attention and
categorisation-like processes, may require only very limited neuron numbers. Thus, brain
size may have less of a relationship with behavioural repertoire and cognitive capacity
than generally assumed, prompting the question of what large brains are for. Larger
brains are, at least partly, a consequence of larger neurons that are necessary in large
animals due to basic biophysical constraints. They also contain greater replication of
neuronal circuits, adding precision to sensory processes, detail to perception, more
parallel processing and enlarged storage capacity. Yet, these advantages are unlikely to
produce the qualitative shifts in behaviour that are often assumed to accompany
increased brain size. Instead, modularity and interconnectivity may be more important
Current Biology, Volume 19, Issue 21, R995-R1008, 17 November 2009
72.A Review of Ant Cuticular Hydrocarbons
Stephen Martin1 and Falko Drijfhout2 [email protected]
1. Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
2. Chemical Ecology Group, School of Physical and Geographical Sciences, Lennard-Jones Laboratory,
Keele University, Keele, UK
We compared the published cuticular hydrocarbon (CHC) profiles of 78 ant species across
5 subfamilies. Almost 1,000 CHCs have been described for these species, composing 187
distinct homologous series and ten hydrocarbon groups. In descending order of
occurrence were: n-alkanes > monomethylalkanes > dimethylalkanes > alkenes >
dienes>> trimethylalkanes>> methylalkenes > methylalkadienes > trienes >
tetramethylalkanes. Odd chain lengths and positions of methyl or double bonds at odd
carbon numbers were far more numerous than even chain-length compounds or bond
positions. Although each species possess its own unique pattern of CHCs, we found no
41
association between CHC profile and phylogeny. The production of the biosynthetically
complex compounds (e.g., methyl branched dienes) by the most primitive living ant
suggests that the basic genetic architecture required to produce the rich diversity of
CHCs was already present prior to their adaptive radiation. Unlike the ubiquitous nalkanes and monomethylalkanes, there is a huge diversity of species-specific
dimethylalkanes that makes them likely candidates for species and nest-mate
discrimination signals.
http://www.springerlink.com/content/h475723350505151/
73.Courtship learning in Drosophila melanogaster: Diverse plasticity of a
reproductive behavior
Leslie C. Griffith1 and Aki Ejima2 [email protected]
Department of Biology, National Center for Behavioral Genomics and Volen Center for Complex
Systems, Brandeis University, Waltham, Massachusetts 02493, USA;
Career-Path Promotion Unit for Young Life Scientists, Kyoto University, Kyoto, Japan 606-8501
Mechanisms for identifying appropriate mating partners are critical for species
propagation. In many species, the male uses multiple sensory modalities to search for
females and to subsequently determine if they are fit and receptive. Males can also use
the information they acquire in this process to change their courtship behavior and
reduce courtship of classes of targets that are inappropriate or unreceptive. In Drosophila,
courtship plasticity, in the form of both nonassociative and associative learning, has been
documented—the type of learning depending on the nature of the trainer. The conditions
in which the male is presented with the training target can profoundly alter the cues that
he finds salient and the longevity of the memory that he forms. With the exception of
habituation and sensitization, these types of plasticity have an operant component in that
the male must be courting to respond to the behavior-altering cues. Courtship plasticity
is therefore a complex and rich range of behaviors rather than a single entity. Our
understanding of these plastic behaviors has been enhanced by recent advances in our
understanding of the circuitry underlying courtship itself and the identification of
chemical cues that drive and modify the behavior. Courtship learning is providing a
window into how animals can use a variety of sensory inputs to modulate a decision
making process at many levels.
Learn. Mem. 2009. 16: 743-750
http://learnmem.cshlp.org/content/16/12/743.abstract
74.Circadian rhythms and the evolution of photoperiodic timing in insects
DAVID S. SAUNDERS
Emeritus Professor, University of Edinburgh, Scotland, U.K.
This review discusses possible evolutionary trends in insect photoperiodism, mainly from
a chronobiological perspective. A crucial step was the forging of a link between the
hormones regulating diapause and the systems of biological rhythms, circadian or
circannual, which have independently evolved in eukaryotes to synchronize physiology
and behaviour to the daily cycles of light and darkness. In many of these responses a
central feature is that the circadian system resets to a constant phase at the beginning of
the subjective night, and then 'measures' the duration of the next scotophase. In
'external coincidence', one version of such a clock, light now has a dual role. First, it
serves to entrain the circadian system to the stream of pulses making up the light/dark
cycle and, second, it regulates the nondiapause/diapause switch in development by
illuminating/not illuminating a specific light sensitive phase falling at the end of the
critical night length. Important work by A. D. Lees on the aphid Megoura viciae using socalled 'night interruption experiments' demonstrates that pulses falling early in the night
42
lead to long-day effects that are reversible by a subsequent dark period longer than the
critical night length and also show maximal sensitivity in the blue–green range of the
spectrum. Pulses falling in the latter half of the night, however, produce long-day effects
that are irreversible by a subsequent long-night and show a spectral sensitivity extending
into the red. With movement to higher latitudes, insects develop genetic clines in various
parameters, including critical night length, the number of long-night cycles needed for
diapause induction, the strength of the response, and the 'depth' or intensity of the
diapause thus induced. Evidence for these and other types of photoperiodic response
suggests that they provided strong selective advantages for insect survival.
Physiological Entomology Volume 34 Issue 4, Pages 301 – 308 Published Online:
19 Nov 2009
Top
Edited by Xin-Cheng Zhao
2009-12-30
43

Insect Frontiers December 2009 Volume 1 Nomber 2

Transcription

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