May 2010 Volume 2 Nomber 5
Insect Frontiers
Mirid bug population dynamics in Bt and non-Bt cotton with different management regimes from 2002–2009. (From Sci- ence 2010 328:1151-1154; Abstract No. 30 in this issue. Without permission). Insect Frontiers, May 2010 Volume 2 Number 5
Insect Behavior 1. Genotype effect on regulation of behaviour by vitellogenin supports reproductive origin of honeybee foraging bias Animal Behaviour Volume 79, Issue 5, May 2010, Pages 1001-1006
2. Relevance of resource-indicating key volatiles and habitat odour for insect orientation Animal Behaviour Volume 79, Issue 5, May 2010, Pages 1077-1086
3. Is mate choice in Drosophila males guided by olfactory or gustatory pheromones? Animal Behaviour Volume 79, Issue 5, May 2010, Pages 1135-1146
4. Multimodal mate assessment by male praying mantids in a sexually cannibalistic mating system Animal Behaviour Volume 79, Issue 5, May 2010, Pages 1165-1172
5. Properties of male ejaculates do not generate geographical variation in female mating tactics in a butterfly Pieris napi Animal Behaviour Volume 79, Issue 5, May 2010, Pages 1173-1179
6. Acoustic Experience Shapes Alternative Mating Tactics and Reproductive Investment in Male Field Crickets Current Biology, Volume 20, Issue 9, 845-849, 22 April 2010
7. Interaction of liquid epicuticular hydrocarbons and tarsal adhesive secretion in Leptinotarsa decemlineata Say (Coleoptera: Chrysomelidae) Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology Volume 196, Number 5 / May, 2010 369-378
8. Minimum viewing angle for visually guided ground speed control in bumblebees Journal of Experimental Biology 213, 1625-1632 (2010)
9. The spatial frequency tuning of optic-flow-dependent behaviors in the bumblebee Bombus impatiens Journal of Experimental Biology 213, 1643-1650 (2010)
10. Comb construction in mixed-species colonies of honeybees, Apis cerana and Apis mellifera Journal of Experimental Biology 213, 1659-1664 (2010)
11. Ant search strategies after interrupted tandem runs Journal of Experimental Biology 213, 1697-1708 (2010)
12. Drosophila fly straight by fixating objects in the face of expanding optic flow Journal of Experimental Biology 213, 1771-1781 (2010)
13. The twilight zone: ambient light levels trigger activity in primitive ants Proc. R. Soc. B 22 May 2010 vol. 277 no. 1687 1531-1538 Insect Frontiers, May 2010 Volume 2 Number 5 Insect Biology 14. Butterfly wing colors: glass scales of Graphium sarpedon cause polarized iridescence and enhance blue/green pigment coloration of the wing membrane Journal of Experimental Biology 213, 1731-1739 (2010)
Insect Biochemistry 15. Light-dependent Phosphorylation of the Drosophila Transient Receptor Potential Ion Channel* The Journal of Biological Chemistry, 285, 14275-14284. May 7, 2010
16. Crystal Structure of the Catalytic Domain of Drosophila β1,4- Galactosyltransferase-7* The Journal of Biological Chemistry, 285, 15619-15626 May 14, 2010
17. The Drosophila Copper Transporter Ctr1C Functions in Male Fertility* The Journal of Biological Chemistry, 285, 17089-17097. May 28, 2010
18. Thermal sensitivity of mitochondrial metabolism in two distinct mitotypes of Drosophila simulans: evaluation of mitochondrial plasticity Journal of Experimental Biology 213, 1665-1675 (2010)
19. Single base–resolution methylome of the silkworm reveals a sparse epigenomic map Nature Biotechnology 28, 516–520 (2010)
Insect Cell Biology 20. Cindr Interacts with Anillin to Control Cytokinesis in Drosophila melanogaster Current Biology, Volume 20, Issue 10, 944-950, 06 May 2010
21. Scarface, a secreted serine protease-like protein, regulates polarized localization of laminin A at the basement membrane of the Drosophila embryo EMBO reports (2010) 11, 373 - 379
22. A distinctive role for focal adhesion proteins in three-dimensional cell motility Nature Cell Biology 12, 598 - 604 (2010)
Insect Chemoreception 23. Behavioral insensitivity to DEET in Aedes aegypti is a genetically determined trait residing in changes in sensillum function PNAS May 11, 2010 vol. 107 no. 19 8575-8580
24. Bombykol receptors in the silkworm moth and the fruit fly PNAS May 18, 2010 vol. 107 no. 20 9436-9439
25. Post-eclosion odor experience modifies olfactory receptor neuron coding in Drosophila PNAS May 25, 2010 vol. 107 no. 21 9855-9860 Insect Frontiers, May 2010 Volume 2 Number 5 Insect Development 26. Neuronal expression of Mgat1 rescues the shortened life span of Drosophila Mgat11 null mutants and increases life span PNAS May 25, 2010 vol. 107 no. 21 9677-9682
Insect Ecology 27. A mathematical model of exposure of non-target Lepidoptera to Bt-maize pollen expressing Cry1Ab within Europe Proc. R. Soc. B 7 May 2010 vol. 277 no. 1686 1417-1425
28. Induced niche shift as an anti-predator response for an endoparasitoid Proc. R. Soc. B 22 May 2010 vol. 277 no. 1687 1475-1480
29. Host sanctions and pollinator cheating in the fig tree–fig wasp mutualism Proc. R. Soc. B 22 May 2010 vol. 277 no. 1687 1481-1488
30. Mirid Bug Outbreaks in Multiple Crops Correlated with Wide-Scale Adoption of Bt Cotton in China Science 28 May 2010:Vol. 328. no. 5982, pp. 1151 – 1154
Insect Evolution 31. MATERNAL EFFECTS, BUT NO GOOD OR COMPATIBLE GENES FOR SPERM COMPETITIVENESS IN AUSTRALIAN CRICKETS Evolution 2010 Volume 64 Issue 5, Pages 1257 - 1266
32. Z LINKAGE OF FEMALE PROMISCUITY GENES IN THE MOTH UTETHEISA ORNATRIX: SUPPORT FOR THE SEXY-SPERM HYPOTHESIS? Evolution 2010 Volume 64 Issue 5, Pages 1267 - 1272
33. THE ROLES OF LIFE-HISTORY SELECTION AND SEXUAL SELECTION IN THE ADAPTIVE EVOLUTION OF MATING BEHAVIOR IN A BEETLE Evolution 2010 Volume 64 Issue 5, Pages 1273 - 1282
34. SEX RATIO DRIVE PROMOTES SEXUAL CONFLICT AND SEXUAL COEVOLUTION IN THE FLY DROSOPHILA PSEUDOOBSCURA Evolution 2010 Volume 64 Issue 5, Pages 1504 – 1509
35. Sexual conflict and the gender load: correlated evolution between population fitness and sexual dimorphism in seed beetles Proc. R. Soc. B 7 May 2010 vol. 277 no. 1686 1345-1352
Insect Genetics 36. Nonallelic Gene Conversion in the Genus Drosophila Genetics, Vol. 185, 95-103, May 2010
37. Hearing in Drosophila Requires TilB, a Conserved Protein Associated With Ciliary Motility Genetics, Vol. 185, 177-188, May 2010,
38. Activation of Sterol Regulatory Element Binding Proteins in the Absence of Scap in Drosophila melanogaster Genetics, Vol. 185, 189-198, May 2010,
Insect Frontiers, May 2010 Volume 2 Number 5 39. The Steroid Molting Hormone Ecdysone Regulates Sleep in Adult Drosophila melanogaster Genetics, Vol. 185, 269-281, May 2010,
40. Muller's Ratchet and the Degeneration of the Drosophila miranda Neo-Y Chromosome Genetics, Vol. 185, 339-348, May 2010,
41. Sexual isolation of male moths explained by a single pheromone response QTL containing four receptor genes PNAS May 11, 2010 vol. 107 no. 19 8660-8665
Insect Learning 42. Electric Shock-Induced Associative Olfactory Learning in Drosophila Larvae Chemical Senses 2010 35(4):335-346; doi:10.1093/chemse/bjq023’
Insect Molecular Biology 43. The miRNA machinery targets Mei-P26 and regulates Myc protein levels in the Drosophila wing The EMBO Journal (2010) 29, 1688 - 1698
44. The molecular basis for water taste in Drosophila Nature 465,91–95 (06 May 2010)
Insect Molecular Ecology 45. Wolbachia modulates Chikungunya replication in Aedes albopictus Molecular Ecology 2010 Volume 19 Issue 9, Pages 1953 - 1964
46. Differential introgression causes genealogical discordance in host races of Acrocercops transecta (Insecta: Lepidoptera) Molecular Ecology 2010 Volume 19 Issue 10, Pages 2106 - 2119
47. Population genetic structure of two primary parasitoids of Spodoptera frugiperda (Lepidoptera), Chelonus insularis and Campoletis sonorensis (Hymenoptera): to what extent is the host plant important? Molecular Ecology 2010 Volume 19 Issue 10, Pages 2168 - 2179
48. Host-associated genetic differentiation in a seed parasitic weevil Rhinusa antirrhini (Coleptera: Curculionidae) revealed by mitochondrial and nuclear sequence data Molecular Ecology 2010 Volume 19 Issue 11, Pages 2286 - 2300
49. Inbreeding in a natural population of the gregarious parasitoid wasp Cotesia glomerata Molecular Ecology 2010 Volume 19 Issue 11, Pages 2336 - 2345
Insect Morphology 50. Female germline stem cell niches of earwigs are structurally simple and different from those of Drosophila melanogaster Journal of Morphology 2010 Volume 271 Issue 5, Pages 634 - 640
Insect Neuroethology 51. Auditory-based defence against gleaning bats in neotropical katydids (Orthoptera: Tettigoniidae) Insect Frontiers, May 2010 Volume 2 Number 5 Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology Volume 196, Number 5 / May, 2010 349-358
52. Mutation of the Drosophila vesicular GABA transporter disrupts visual figure detection Journal of Experimental Biology 213, 1717-1730 (2010)
Insect Neuroscience 53. Response competition associated with right–left antennal asymmetries of new and old olfactory memory traces in honeybees Behavioural Brain Research Volume 209, Issue 1, 1 May 2010, Pages 36-41
54. Neural Activity in the Central Complex of the Insect Brain Is Linked to Locomotor Changes Current Biology, Volume 20, Issue 10, 921-926, 06 May 2010
55. Visual experience and age affect synaptic organization in the mushroom bodies of the desert ant Cataglyphis fortis Developmental Neurobiology 2010 Volume 70 Issue 6, Pages 408 - 423
56. The Amiloride-Sensitive Epithelial Na+ Channel PPK28 Is Essential for Drosophila Gustatory Water Reception The Journal of Neuroscience, May 5, 2010, 30(18):6247-6252 57. Long-Term Memory Leads to Synaptic Reorganization in the Mushroom Bodies: A Memory Trace in the Insect Brain? The Journal of Neuroscience, May 5, 2010, 30(18):6461-6465;
58. Calcium Activates a Chloride Conductance Likely Involved in Olfactory Receptor Neuron Repolarization in the Moth Spodoptera littoralis The Journal of Neuroscience, May 5, 2010, 30(18):6323-6333;
59. Axonal Degeneration Is Regulated by the Apoptotic Machinery or a NAD+- Sensitive Pathway in Insects and Mammals The Journal of Neuroscience, May 5, 2010, 30(18):6375-6386;
60. Sialyltransferase Regulates Nervous System Function in Drosophila The Journal of Neuroscience, May 5, 2010, 30(18):6466-6476;
61. Light-Mediated TIM Degradation within Drosophila Pacemaker Neurons (s-LNvs) Is Neither Necessary nor Sufficient for Delay Zone Phase Shifts Neuron Volume 66, Issue 3, 13 May 2010, Pages 378-385
62. Drosophila TRPA1 channel mediates chemical avoidance in gustatory receptor neurons PNAS May 4, 2010 vol. 107 no. 18 8440-8445
Insect review 63. Short-term memories in Drosophila are governed by general and specific genetic systems Learn. Mem. 2010. 17: 246-251
64. Nature versus nurture in social insect caste differentiation Trends in Ecology & Evolution Volume 25, Issue 5, May 2010, Pages 275-282 Insect Frontiers, May 2010 Volume 2 Number 5
Insect Behavior 1. Genotype effect on regulation of behaviour by vitellogenin supports reproductive origin of honeybee foraging bias
Kate E. Ihlea, , , Robert E. Page Jr.a, Katy Fredericka, M. Kim Fondrka and Gro V. Amdama, b a School of Life Sciences, Arizona State University, Tempe, U.S.A. b Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Aas, Norway
In honeybee colonies, food collection is performed by a group of mostly sterile females called workers. After an initial nest phase, workers begin foraging for nectar and pollen, but tend to bias their collection towards one or the other. Although foraging choices of honeybees are influenced by vitellogenin, an egg-yolk precursor protein, workers typically do not lay eggs. The forager reproductive ground plan hypothesis (RGPH) proposes an evolutionary path in which the behavioural bias towards collecting nectar or pollen on foraging trips is influenced by variation in reproductive physiology, such as hormone levels and vitellogenin (vg) gene expression. Recently, the connections between vitellogenin and foraging behaviour were challenged by Oldroyd & Beekman (2008), who concluded from their study that the ovary, and especially vitellogenin, played no role in foraging behaviour of bees. We address their challenge directly by manipulating vg expression by RNA interference (RNAi) mediated gene knockdown in two honeybee genotypes with different foraging behaviour and reproductive physiology. We found that vg affected the food-loading decisions of the workers only in the genotype in which the timing of foraging onset (by age) was also sensitive to vitellogenin levels. In the second genotype, changing vitellogenin levels did not affect foraging onset or bias. The effect of vitellogenin on workers' age at foraging onset is explained by the well-supported double repressor hypothesis (DHR), which describes a mutually inhibitory relationship between vitellogenin and juvenile hormone (JH), an endocrine factor that influences development, reproduction and behaviour in many insects. These results support the RGPH and demonstrate how it intersects with an established mechanism of honeybee behavioural control. Animal Behaviour Volume 79, Issue 5, May 2010, Pages 1001-1006 http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6W9W-4YMBW4C- 1&_user=10&_coverDate=05%2F31%2F2010&_rdoc=6&_fmt=high&_orig=browse&_srch=doc- info(%23toc%236693%232010%23999209994%231890824%23FLA%23display%23Volume)&_cdi=6693&_sort=d&_docanchor=&_ct=27&_acct=C0 00050221&_version=1&_urlVersion=0&_userid=10&md5=9625637917735d43bf908699c2c0aab2
2. Relevance of resource-indicating key volatiles and habitat odour for insect orientation
I. Beyaerta, N. Wäschkea, A. Scholza, M. Varamab, 1, A. Reineckec, 2 and M. Hilkera, , a Institute of Biology, Freie Universität Berlin, Germany b Finnish Forest Research Institute, Finland c Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Germany
Olfactory orientation by insects may be guided by specific volatile blends released from sites where resources are present. Such blends need to be recognized against the odorous background of the habitat. The egg parasitoid Closterocerus ruforum is known to be attracted to plant volatiles induced by egg deposition of its herbivorous host, the pine sawfly Diprion pini. The parasitoid has to detect this volatile signal against a background of other pine volatiles (i.e. odour from pine without host eggs). Previous studies have shown that attractive resource-indicating odour (pine with host eggs) and nonattractive habitat odour (pine without eggs) differ only by enhanced quantities of (E)-β-farnesene in the resource-indicating odour. However, (E)-β-farnesene per se was not attractive. We studied the relevance of quantitative ratios of (E)-β-farnesene and other pine volatiles present in the habitat for parasitoid orientation by electrophysiological methods (EAG) and behavioural (olfactometer) assays. Seven of 12 terpenoid pine volatiles elicited an Insect Frontiers, May 2010 Volume 2 Number 5 EAG response. In tests of the parasitoid's behavioural response to EAG-active volatiles, a blend of five components (including (E)-β-farnesene) was sufficient to attract the parasitoid but only when the ratio of (E)-β-farnesene and the other compounds matched that in odour from egg-laden pine. Since the quantities of volatiles from egg-laden and egg-free pine are not significantly different except for (E)-β-farnesene, our results show that the quantity of a resource-indicating key compound (here (E)-β-farnesene) is validated by its ratio to quantities of background volatiles emitted by both the resource and the habitat. Animal Behaviour Volume 79, Issue 5, May 2010, Pages 1077-1086 http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6W9W-4YKF71Y- 2&_user=10&_coverDate=05%2F31%2F2010&_rdoc=15&_fmt=high&_orig=browse&_srch=doc- info(%23toc%236693%232010%23999209994%231890824%23FLA%23display%23Volume)&_cdi=6693&_sort=d&_docanchor=&_ct=27&_acct=C0 00050221&_version=1&_urlVersion=0&_userid=10&md5=35ffdac412610c19d63f9fc42c921f80
3. Is mate choice in Drosophila males guided by olfactory or gustatory pheromones?
Claude Everaerts , a, , Fabien Lacaillea and Jean-François Ferveura a Centre des Sciences du Goût et de l'Alimentation, UMR6265 CNRS, UMR1324 INRA, Université de Bourgogne, France
Drosophila melanogaster flies use both olfactory and taste systems to detect sex pheromones and select the most suitable mate for reproduction. In nature, flies often face multiple potential partners and should have an acute sensory ability to discriminate between different pheromonal bouquets. We investigated both the pheromones and the chemosensory neurons influencing Drosophila mate choice. We measured various courtship traits in single tester males simultaneously presented with two target male and/or female flies carrying different pheromonal bouquets (pairs of control flies of the same or different sex, same-sex target pairs of pheromonal variant strains). The courtship traits reflected the perception of either olfactory cues perceived before or gustatory cues perceived after the first physical taste contact. Our results suggest that male mate choice exists in D. melanogaster and that male discrimination between potential mates could be a two-step process involving chemical cues perceived before and after the first gustatory contact. In addition, when a male was simultaneously presented with two potential sexual partners, the olfactory and gustatory cues he used depended on the pheromonal patterns of both flies, but his response could also depend on additional effects resulting from the simultaneous perception of the two flies, leading to a nonlinear choice of a sexual partner. Moreover, some tester males with genetically altered gustatory receptor neurons strongly changed their partner preference, indicating that the fly's peripheral nervous system is essential for pheromonal detection and mate choice. Animal Behaviour Volume 79, Issue 5, May 2010, Pages 1135-1146 http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6W9W-4YP6SKJ- 1&_user=10&_coverDate=05%2F31%2F2010&_rdoc=22&_fmt=high&_orig=browse&_srch=doc- info(%23toc%236693%232010%23999209994%231890824%23FLA%23display%23Volume)&_cdi=6693&_sort=d&_docanchor=&_ct=27&_acct=C0 00050221&_version=1&_urlVersion=0&_userid=10&md5=19cca7e457c4c58078d79fa878652b74
4. Multimodal mate assessment by male praying mantids in a sexually cannibalistic mating system
Katherine L. Barrya, , , Gregory I. Holwella, b and Marie E. Herbersteina a Department of Biological Sciences, Macquarie University, Australia b School of Biological Sciences, University of Auckland, New Zealand
The traditional view of sexual selection has been that of competing males and choosy females; however, more recently it has been recognized that males may exhibit mate choice when females vary in quality and when males suffer costs associated with mating. Sexually cannibalistic mating systems provide an opportunity to examine male mate choice further: the high costs potentially involved in the mating process for males, as well as variation in female quality, predict male mate choice. We used the praying mantid Pseudomantis albofimbriata to determine the effect of female body condition on male Insect Frontiers, May 2010 Volume 2 Number 5 mate choice in a system with frequent precopulatory sexual cannibalism. Female body condition is positively correlated with fecundity and negatively correlated with the propensity to cannibalize, so we predicted males would strongly prefer females in good condition to maximize their reproductive potential. Results of our simultaneous choice tests showed that males use chemical and visual cues for mate location and assessment, and that they can use either of these sensory modalities to distinguish and choose between females differing in body condition, with a significant preference for good- condition females. However, surprisingly, males rarely rejected poor-condition females in the more ecologically relevant scenario of only one immediate potential mate and both sensory modes available to them, which may be explained by the strong scramble competition known for praying mantid systems. These results show that even when female quality varies and the cost of mating for males is substantial, male mate rejection does not always evolve. Animal Behaviour Volume 79, Issue 5, May 2010, Pages 1165-1172 http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6W9W-4YN4X7N- 1&_user=10&_coverDate=05%2F31%2F2010&_rdoc=25&_fmt=high&_orig=browse&_srch=doc- info(%23toc%236693%232010%23999209994%231890824%23FLA%23display%23Volume)&_cdi=6693&_sort=d&_docanchor=&_ct=27&_acct=C0 00050221&_version=1&_urlVersion=0&_userid=10&md5=140a62f6ba1cdbacd4aca150f724754c
5. Properties of male ejaculates do not generate geographical variation in female mating tactics in a butterfly Pieris napi
Panu Välimäki , a, and Arja Kaitalaa a Department of Biology, University of Oulu, Finland
Polyandry brings about benefits for females but, from the males' perspective, if there is a possibility of females mating with multiple partners, male characteristics that prevent or delay remating of females are favoured, which may result in antagonistic coevolution between the sexes. The green-veined white butterfly, Pieris napi, is a predominantly polyandrous species with male nutrient donation transferred within the ejaculate at mating. Male ejaculates that are exaggerated in size or content can be interpreted as a means to reduce female remating. We explored whether geographical variation in the degree of polyandry among P. napi populations results from variation in the male's ability to manipulate females to mate at a suboptimal rate. Females that mated with a larger male capable of delivering a large spermatophore remated later than those that mated with a smaller male. However, we found no spatial variation in sexual size dimorphism or relative ejaculate size. Moreover, the mating frequency of females was not affected by the origin of males with which they mated. We argue that even if large male ejaculates evolved to ensure paternity of a given male with negative side-effects on female fitness, female counteradaptations conceal possible implications of antagonistic coevolution. Geographical variation in female mating frequency is probably maintained by selection acting upon female life history traits associated with the degree of polyandry. Animal Behaviour Volume 79, Issue 5, May 2010, Pages 1173-1179 http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6W9W-4YN4X7N- 2&_user=10&_coverDate=05%2F31%2F2010&_rdoc=26&_fmt=high&_orig=browse&_srch=doc- info(%23toc%236693%232010%23999209994%231890824%23FLA%23display%23Volume)&_cdi=6693&_sort=d&_docanchor=&_ct=27&_acct=C0 00050221&_version=1&_urlVersion=0&_userid=10&md5=d2317b0ce056b1dd79a1fd52b01b16d7
6. Acoustic Experience Shapes Alternative Mating Tactics and Reproductive Investment in Male Field Crickets
Nathan W. Bailey , Brian Gray, Marlene Zuk Department of Biology, University of California, Riverside, Riverside, CA 92521, USA
Highlights Sexual signals provide information about the social environment to developing animals. Juvenile male field crickets use those signals to shape adult reproductive traits. Acoustic experience decreases the likelihood of adopting satellite mating tactics. However, acoustic experience increases condition and investment in reproductive tissues Summary Developmental plasticity allows juvenile animals to assess environmental cues and adaptively shape behavioral and morphological traits to maximize fitness in their Insect Frontiers, May 2010 Volume 2 Number 5 adult environment [1]. Sexual signals are particularly conspicuous cues, making them likely candidates for mediating such responses. Plasticity in male reproductive traits is a common phenomenon, but empirical evidence for signal-mediated plasticity in males is lacking. We tested whether experience of acoustic sexual signals during juvenile stages influences the development of three adult traits in the continuously breeding field cricket Teleogryllus oceanicus: male mating tactics, reproductive investment, and condition. All three traits were affected by juvenile acoustic experience. Males of this species produce a long-range calling song to attract receptive females, but they can also behave as satellites by parasitizing other males' calls [2]. Males reared in an environment mimicking a population with many calling males were less likely to exhibit satellite behavior, invested more in reproductive tissues, and attained higher condition than males reared in a silent environment. These results contrast with other studies [3] and demonstrate how the effects of juvenile social experience on adult male morphology, reproductive investment, and behavior may subsequently influence sexual selection and phenotypic evolution. Current Biology, Volume 20, Issue 9, 845-849, 22 April 2010 http://www.cell.com/current-biology/abstract/S0960-9822%2810%2900348-9
7. Interaction of liquid epicuticular hydrocarbons and tarsal adhesive secretion in Leptinotarsa decemlineata Say (Coleoptera: Chrysomelidae)
Stefanie F. Geiselhardt1 , Stefan Lamm1, Claudia Gack1 and Klaus Peschke1 Institut für Biologie I, Albert-Ludwigs-Universität Freiburg i.Br., Hauptstr. 1, 79104 Freiburg, Germany
Species of various insect orders possess specialised tarsal adhesive structures covered by a thin liquid film, which is deposited in the form of footprints. This adhesive liquid has been suggested to be chemically and physiologically related to the epicuticular lipid layer, which naturally covers the body of insects and acts as the prime barrier to environmental stresses, such as desiccation. The functional efficiency of the layer, however, is jeopardised by partial melting that may occur at physiological temperatures. In this study, light microscopic images of elytral prints show that the epicuticular lipid layer of the Colorado potato beetle Leptinotarsa decemlineata actually is partially liquid and chemical investigations reveal the high similarity of the epicuticular hydrocarbon pattern and the tarsal liquid. By means of chemical manipulation of the surface hydrocarbon composition of live beetles, the substance exchange between their tarsal adhesive hairs and the body surface is monitored. Histological sections of L. decemlineata tarsi, furthermore, reveal glandular cells connected to individual adhesive setae and departing from these results, an idea of a general mechanism of tarsal secretion is developed and discussed in a functional–ecological context. Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology Volume 196, Number 5 / May, 2010 369-378 http://www.springerlink.com/content/8170h71552212g42/
8. Minimum viewing angle for visually guided ground speed control in bumblebees
Emily Baird*, Torill Kornfeldt and Marie Dacke [email protected] Lund University, Department of Biology, Helgonavägen 3, 22362 Lund, Sweden
To control flight, flying insects extract information from the pattern of visual motion generated during flight, known as optic flow. To regulate their ground speed, insects such as honeybees and Drosophila hold the rate of optic flow in the axial direction (front-to- back) constant. A consequence of this strategy is that its performance varies with the minimum viewing angle (the deviation from the frontal direction of the longitudinal axis of the insect) at which changes in axial optic flow are detected. The greater this angle, the later changes in the rate of optic flow, caused by changes in the density of the environment, will be detected. The aim of the present study is to examine the mechanisms of ground speed control in bumblebees and to identify the extent of the Insect Frontiers, May 2010 Volume 2 Number 5 visual range over which optic flow for ground speed control is measured. Bumblebees were trained to fly through an experimental tunnel consisting of parallel vertical walls. Flights were recorded when (1) the distance between the tunnel walls was either 15 or 30 cm, (2) the visual texture on the tunnel walls provided either strong or weak optic flow cues and (3) the distance between the walls changed abruptly halfway along the tunnel's length. The results reveal that bumblebees regulate ground speed using optic flow cues and that changes in the rate of optic flow are detected at a minimum viewing angle of 23–30 deg., with a visual field that extends to approximately 155 deg. By measuring optic flow over a visual field that has a low minimum viewing angle, bumblebees are able to detect and respond to changes in the proximity of the environment well before they are encountered. Journal of Experimental Biology 213, 1625-1632 (2010) http://jeb.biologists.org/cgi/content/abstract/213/10/1625
9. The spatial frequency tuning of optic-flow-dependent behaviors in the bumblebee Bombus impatiens
Jonathan P. Dyhr1,2,* and Charles M. Higgins2,3 [email protected] 1 Graduate Program in Neuroscience, The University of Arizona, 1040 E. 4th Street, Tucson, AZ 85721- 0077, USA 2 Department of Neuroscience, The University of Arizona, 1040 E. 4th Street, Tucson, AZ 85721-0077, USA 3 Department of Electrical and Computer Engineering, The University of Arizona, 1040 E. 4th Street, Tucson, AZ 85721-0077, USA
Insects use visual estimates of flight speed for a variety of behaviors, including visual navigation, odometry, grazing landings and flight speed control, but the neuronal mechanisms underlying speed detection remain unknown. Although many models and theories have been proposed for how the brain extracts the angular speed of the retinal image, termed optic flow, we lack the detailed electrophysiological and behavioral data necessary to conclusively support any one model. One key property by which different models of motion detection can be differentiated is their spatiotemporal frequency tuning. Numerous studies have suggested that optic-flow-dependent behaviors are largely insensitive to the spatial frequency of a visual stimulus, but they have sampled only a narrow range of spatial frequencies, have not always used narrowband stimuli, and have yielded slightly different results between studies based on the behaviors being investigated. In this study, we present a detailed analysis of the spatial frequency dependence of the centering response in the bumblebee Bombus impatiens using sinusoidal and square wave patterns. Journal of Experimental Biology 213, 1643-1650 (2010) http://jeb.biologists.org/cgi/content/abstract/213/10/1643
10. Comb construction in mixed-species colonies of honeybees, Apis cerana and Apis mellifera
Ming-Xian Yang1,2, Ken Tan2,3, Sarah E. Radloff4,*, Mananya Phiancharoen5 and H. Randall Hepburn1,2 [email protected] 1 Department of Zoology and Entomology, Rhodes University, Grahamstown 6140, South Africa 2 Eastern Bee Research Institute, Yunnan Agricultural University, Heilongtan, Kunming, Yunnan Province 650201, People's Republic of China 3 Xishuangbanna Tropical Botanical Garden, Chinese Academy of Science, Kunming, Yunnan Province, 650223, People's Republic of China 4 Department of Statistics, Rhodes University, PO Box 94, Grahamstown 6140, South Africa 5 Rachaburi campus, King Mongkut's University of Technology Thonburi, 126 Prachautid Road, Bangkok 10140, Thailand
Comb building in mixed-species colonies of Apis cerana and Apis mellifera was studied. Two types of cell-size foundation were made from the waxes of these species and inserted into mixed colonies headed either by an A. cerana or an A. mellifera queen. The colonies did not discriminate between the waxes but the A. cerana cell-size foundation was modified during comb building by the workers of both species. In pure A. cerana Insect Frontiers, May 2010 Volume 2 Number 5 colonies workers did not accept any foundation but secreted wax and built on foundation in mixed colonies. Comb building is performed by small groups of workers through a mechanism of self-organisation. The two species cooperate in comb building and construct nearly normal combs but they contain many irregular cells. In pure A. mellifera colonies, the A. cerana cell size was modified and the queens were reluctant to lay eggs on such combs. In pure A. cerana colonies, the A. mellifera cell size was built without any modification but these cells were used either for drone brood rearing or for food storing. The principal elements of comb-building behaviour are common to both species, which indicates that they evolved prior to and were conserved after speciation. Journal of Experimental Biology 213, 1659-1664 (2010) http://jeb.biologists.org/cgi/content/abstract/213/10/1659
11. Ant search strategies after interrupted tandem runs
Nigel R. Franks1,*, Thomas O. Richardson2,1, Samantha Keir1, Stephen J. Inge1, Frederic Bartumeus3 and Ana B. Sendova-Franks2 [email protected] 1 School of Biological Sciences, University of Bristol, Woodland Road, Bristol, BS8 1UG, UK 2 Department of Mathematics and Statistics, BIT, University of the West of England, Frenchay Campus, Coldharbour Lane, Bristol, BS16 1QY, UK 3 Centre d'Estudis Avançats de Blanes (CEAB-CSIC) C/Accés Cala Sant Francesc, 14, 17300 Blanes, Girona, Spain
Tandem runs are a form of recruitment in ants. During a tandem run, a single leader teaches one follower the route to important resources such as sources of food or better nest sites. In the present study, we investigate what tandem leaders and followers do, in the context of nest emigration, if their partner goes missing. Our experiments involved removing either leaders or followers at set points during tandem runs. Former leaders first stand still and wait for their missing follower but then most often proceed alone to the new nest site. By contrast, former followers often first engage in a Brownian search, for almost exactly the time that their former leader should have waited for them, and then former followers switch to a superdiffusive search. In this way, former followers first search their immediate neighbourhood for their lost leader before becoming ever more wide ranging so that in the absence of their former leader they can often find the new nest, re-encounter the old one or meet a new leader. We also show that followers gain useful information even from incomplete tandem runs. These observations point to the important principle that sophisticated communication behaviours may have evolved as anytime algorithms, i.e. procedures that are beneficial even if they do not run to completion. Journal of Experimental Biology 213, 1697-1708 (2010) http://jeb.biologists.org/cgi/content/abstract/213/10/1697
12. Drosophila fly straight by fixating objects in the face of expanding optic flow
Michael B. Reiser1,* and Michael H. Dickinson1,2 [email protected] 1 Department of Computational and Neural Systems, California Institute of Technology, Pasadena, CA 91125, USA 2 Department of Biology, California Institute of Technology, Pasadena, CA 91125, USA
Flies, like all animals that depend on vision to navigate through the world, must integrate the optic flow created by self-motion with the images generated by prominent features in their environment. Although much is known about the responses of Drosophila melanogaster to rotating flow fields, their reactions to the more complex patterns of motion that occur as they translate through the world are not well understood. In the present study we explore the interactions between two visual reflexes in Drosophila: object fixation and expansion avoidance. As a fly flies forward, it encounters an expanding visual flow field. However, recent results have demonstrated that Drosophila strongly turn away from patterns of expansion. Given the strength of this reflex, it is difficult to explain how flies make forward progress through a visual landscape. This paradox is partially resolved by the finding reported here that when undergoing flight Insect Frontiers, May 2010 Volume 2 Number 5 directed towards a conspicuous object, Drosophila will tolerate a level of expansion that would otherwise induce avoidance. This navigation strategy allows flies to fly straight when orienting towards prominent visual features. Journal of Experimental Biology 213, 1771-1781 (2010) http://jeb.biologists.org/cgi/content/abstract/213/10/1771
13. The twilight zone: ambient light levels trigger activity in primitive ants
Ajay Narendra*, Samuel F. Reid and Jan M. Hemmi [email protected] ARC Centre of Excellence in Vision Science and Centre for Visual Sciences, Research School of Biology, The Australian National University, Canberra, Australia
Many animals become active during twilight, a narrow time window where the properties of the visual environment are dramatically different from both day and night. Despite the fact that many animals including mammals, reptiles, birds and insects become active in this specific temporal niche, we do not know what cues trigger this activity. To identify the onset of specific temporal niches, animals could anticipate the timing of regular events or directly measure environmental variables. We show that the Australian bull ant, Myrmecia pyriformis, starts foraging only during evening twilight throughout the year. The onset occurs neither at a specific temperature nor at a specific time relative to sunset, but at a specific ambient light intensity. Foraging onset occurs later when light intensities at sunset are brighter than normal or earlier when light intensities at sunset are darker than normal. By modifying ambient light intensity experimentally, we provide clear evidence that ants indeed measure light levels and do not rely on an internal rhythm to begin foraging. We suggest that the reason for restricting the foraging onset to twilight and measuring light intensity to trigger activity is to optimize the trade-off between predation risk and ease of navigation. Proc. R. Soc. B 22 May 2010 vol. 277 no. 1687 1531-1538 http://rspb.royalsocietypublishing.org/content/277/1687/1531.abstract
Insect Biology 14. Butterfly wing colors: glass scales of Graphium sarpedon cause polarized iridescence and enhance blue/green pigment coloration of the wing membrane
Doekele G. Stavenga1,*, Marco A. Giraldo1,2 and Hein L. Leertouwer1 [email protected] 1 Department of Neurobiophysics, University of Groningen, Physics-Chemistry Building, Nijenborgh 4, Groningen, 9747 AG, The Netherlands 2 Institute of Physics, University of Antioquia, Medellín, AA 1226, Colombia
The wings of the swordtail butterfly Graphium sarpedon nipponum contain the bile pigment sarpedobilin, which causes blue/green colored wing patches. Locally the bile pigment is combined with the strongly blue-absorbing carotenoid lutein, resulting in green wing patches and thus improving camouflage. In the dorsal forewings, the colored patches lack the usual wing scales, but instead have bristles. We have found that on the ventral side most of these patches have very transparent scales that enhance, by reflection, the wing coloration when illuminated from the dorsal side. These glass scales furthermore create a strongly polarized iridescence when illuminated by obliquely incident light from the ventral side, presumably for intraspecific signaling. A few ventral forewing patches have diffusely scattering, white scales that also enhance the blue/green wing coloration when observed from the dorsal side. Journal of Experimental Biology 213, 1731-1739 (2010) http://jeb.biologists.org/cgi/content/abstract/213/10/1731
Insect Biochemistry 15. Light-dependent Phosphorylation of the Drosophila Transient Receptor Potential Ion Channel*
Insect Frontiers, May 2010 Volume 2 Number 5 Olaf Voolstra‡,1, Katherina Beck‡,2, Claudia Oberegelsbacher‡, Jens Pfannstiel‡§ and Armin Huber‡§[email protected] From the ‡Department of Biosensorics, Institute of Physiology, and the §Life Science Center, University of Hohenheim, 70599 Stuttgart, Germany
The Drosophila phototransduction cascade terminates in the opening of an ion channel, designated transient receptor potential (TRP). TRP has been shown to become phosphorylated in vitro, suggesting regulation of the ion channel through posttranslational modification. However, except for one phosphorylation site, Ser982, which was analyzed by functional in vivo studies (Popescu, D. C., Ham, A. J., and Shieh, B. H. (2006) J. Neurosci. 26, 8570–8577), nothing is known about the role of TRP phosphorylation in vivo. Here, we report the identification of 21 TRP phosphorylation sites by a mass spectrometry approach. 20 phosphorylation sites are located in the C- terminal portion of the channel, and one site is located near the N terminus. All 21 phosphorylation sites were also identified in the inaCP209 mutant, indicating that phosphorylation of TRP at these sites occurred independently from the eye-enriched protein kinase C. Relative quantification of phosphopeptides revealed that at least seven phosphorylation sites were predominantly phosphorylated in the light, whereas one site, Ser936, was predominantly phosphorylated in the dark. We show that TRP phosphorylated at Ser936 was located in the rhabomere. Light-dependent changes in the phosphorylation state of this site occurred within minutes. The dephosphorylation of TRP at Ser936 required activation of the phototransduction cascade. The Journal of Biological Chemistry, 285, 14275-14284. May 7, 2010 http://www.jbc.org/content/285/19/14275.abstract
16. Crystal Structure of the Catalytic Domain of Drosophila β1,4- Galactosyltransferase-7*
Boopathy Ramakrishnan‡§ and Pradman K. Qasba‡,[email protected] From the ‡Structural Glycobiology Section and §Basic Research Program, SAIC-Frederick, Inc., Center for Cancer Research Nanobiology Program, Center for Cancer Research, NCI, National Institutes of Health, Frederick, Maryland 21702
The β1,4-galactosyltransferase-7 (β4Gal-T7) enzyme, one of seven members of the β4Gal-T family, transfers in the presence of manganese Gal from UDP-Gal to an acceptor sugar (xylose) that is attached to a side chain hydroxyl group of Ser/Thr residues of proteoglycan proteins. It exhibits the least protein sequence similarity with the other family members, including the well studied family member β4Gal-T1, which, in the presence of manganese, transfers Gal from UDP-Gal to GlcNAc. We report here the crystal structure of the catalytic domain of β4Gal-T7 from Drosophila in the presence of manganese and UDP at 1.81 Å resolution. In the crystal structure, a new manganese ion- binding motif (HXH) has been observed. Superposition of the crystal structures of β4Gal- T7 and β4Gal-T1 shows that the catalytic pocket and the substrate-binding sites in these proteins are similar. Compared with GlcNAc, xylose has a hydroxyl group (instead of an N-acetyl group) at C2 and lacks the CH2OH group at C5; thus, these protein structures show significant differences in their acceptor-binding site. Modeling of xylose in the acceptor-binding site of the β4Gal-T7 crystal structure shows that the aromatic side chain of Tyr177 interacts strongly with the C5 atom of xylose, causing steric hindrance to any additional group at C5. Because Drosophila Cd7 has a 73% protein sequence similarity to human Cd7, the present crystal structure offers a structure-based explanation for the mutations in human Cd7 that have been linked to Ehlers-Danlos syndrome. The Journal of Biological Chemistry, 285, 15619-15626 May 14, 2010 http://www.jbc.org/content/285/20/15619.abstract
Insect Biochemistry 17. The Drosophila Copper Transporter Ctr1C Functions in Male Fertility*
Dominik Steiger‡, Michael Fetchko‡, Alla Vardanyan‡, Lilit Atanesyan‡, Kurt Steiner‡, Michelle L. Turski§, Dennis J. Thiele§, Oleg Georgiev‡ and Walter Schaffner‡,[email protected] Insect Frontiers, May 2010 Volume 2 Number 5 From the ‡Institute of Molecular Life Sciences, University of Zurich, CH-8057 Zurich, Switzerland and the §Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710
Living organisms have evolved intricate systems to harvest trace elements from the environment, to control their intracellular levels, and to ensure adequate delivery to the various organs and cellular compartments. Copper is one of these trace elements. It is at the same time essential for life but also highly toxic, not least because it facilitates the generation of reactive oxygen species. In mammals, copper uptake in the intestine and copper delivery into other organs are mediated by the copper importer Ctr1. Drosophila has three Ctr1 homologs: Ctr1A, Ctr1B, and Ctr1C. Earlier work has shown that Ctr1A is an essential gene that is ubiquitously expressed throughout development, whereas Ctr1B is responsible for efficient copper uptake in the intestine. Here, we characterize the function of Ctr1C and show that it functions as a copper importer in the male germline, specifically in maturing spermatocytes and mature sperm. We further demonstrate that loss of Ctr1C in a Ctr1B mutant background results in progressive loss of male fertility that can be rescued by copper supplementation to the food. These findings hint at a link between copper and male fertility, which might also explain the high Ctr1 expression in mature mammalian spermatozoa. In both mammals and Drosophila, the X chromosome is known to be inactivated in the male germline. In accordance with such a scenario, we provide evidence that in Drosophila, the autosomal Ctr1C gene originated as a retrogene copy of the X-linked Ctr1A, thus maintaining copper delivery during male spermatogenesis. The Journal of Biological Chemistry, 285, 17089-17097. May 28, 2010 http://www.jbc.org/content/285/22/17089.abstract
18. Thermal sensitivity of mitochondrial metabolism in two distinct mitotypes of Drosophila simulans: evaluation of mitochondrial plasticity
Nicolas Pichaud1, Etienne Hébert Chatelain1, J. William O. Ballard2, Robert Tanguay3, Geneviève Morrow3 and Pierre U. Blier1,* [email protected] 1 Laboratoire de biologie intégrative, Département de Biologie, Université du Québec à Rimouski, 300 Allée des Ursulines, Rimouski, Québec, Canada, G5L 3A1 2 School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney 2052, Australia 3 Laboratoire de Génétique Cellulaire et développementale, Département de Médecine, Institut de Biologie intégrative et des systèmes, 1030 ave de la Médecine, Université Laval, Québec, Canada, G1V 0A6
The overall aim of this study was to (1) evaluate the adaptive value of mitochondrial DNA by comparing mitochondrial performance in populations possessing different haplotypes and distribution, and to (2) evaluate the sensitivity of different enzymes of the electron transport system (ETS) during temperature-induced changes. We measured the impact of temperature of mitochondrial respiration and several key enzymes of mitochondrial metabolism in two mitotypes (siII and siIII) of Drosophila simulans. The temperature dependencies of oxygen consumption for mitochondria isolated from flight muscle was assessed with complex I substrates (pyruvate + malate + proline) and with sn glycerol- 3-phosphate (to reduce complex III via glycerophosphate dehydrogenase) in both coupled and uncoupled states. Activities of citrate synthase, cytochrome c oxidase (COX), catalase and aconitase, and the excess capacity of COX at high convergent pathway flux were also measured as a function of temperature. Overall, our results showed that functional differences between the two mitotypes are few. Results suggest that differences between the two mitotypes could hardly explain the temperature-specific differences measured in mitochondria performances. It suggests that some other factor(s) may be driving the maintenance of mitotypes. We also show that the different enzymes of the ETS have different thermal sensitivities. The catalytic capacities of these enzymes vary with temperature changes, and the corresponding involvement of the different steps on mitochondrial regulation probably varies with temperature. For example, the excess COX capacity is low, even non-existent, at high and intermediate Insect Frontiers, May 2010 Volume 2 Number 5 temperatures (18°C, 24°C and 28°C) whereas it is quite high at a lower temperature (12°C), suggesting release of respiration control by COX at low temperature. Journal of Experimental Biology 213, 1665-1675 (2010) http://jeb.biologists.org/cgi/content/abstract/213/10/1665
19. Single base–resolution methylome of the silkworm reveals a sparse epigenomic map
Hui Xiang, Jingde Zhu, Quan Chen, Fangyin Dai, Xin Li, Muwang Li, Hongyu Zhang, Guojie Zhang, Dong Li, Yang Dong, Li Zhao, Ying Lin, Daojun Cheng, Jian Yu, Jinfeng Sun,Xiaoyu Zhou, Kelong Ma, Yinghua He, Yangxing Zhao, Shicheng Guo, Mingzhi Ye, Guangwu Guo, Yingrui Li, Ruiqiang Li, Xiuqing Zhang, Lijia Ma, Karsten Kristiansen, Qiuhong Guo, Jianhao Jiang, Stephan Beck, Qingyou Xia, Wen Wang & Jun Wang CAS-Max Planck Junior Research Group, State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, The Chinese Academy of Sciences, Kunming, China. BGI-Shenzhen, Shenzhen, China Cancer Epigenetics and Gene Therapy Program, The State-key Laboratory for Oncogenes and Related Genes, Shanghai Cancer Institute, Shanghai Jiaotong University, Shanghai, China. Cancer Epigenetics Laboratory, Obstetrics and Gynecology Hospital, Fudan University, Shanghai, China. The Key Sericultural Laboratory of Agricultural Ministry, College of Biotechnology, Institute of Sericulture and Systems Biology, Southwest University, Chongqing, China. Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, China. Department of Biology, University of Copenhagen, Denmark. Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, Shanghai, China. UCL Cancer Institute, University College London, London, UK.
Epigenetic regulation in insects may have effects on diverse biological processes. Here we survey the methylome of a model insect, the silkworm Bombyx mori, at single-base resolution using Illumina high-throughput bisulfite sequencing (MethylC-Seq). We conservatively estimate that 0.11% of genomic cytosines are methylcytosines, all of which probably occur in CG dinucleotides. CG methylation is substantially enriched in gene bodies and is positively correlated with gene expression levels, suggesting it has a positive role in gene transcription. We find that transposable elements, promoters and ribosomal DNAs are hypomethylated, but in contrast, genomic loci matching small RNAs in gene bodies are densely methylated. This work contributes to our understanding of epigenetics in insects, and in contrast to previous studies of the highly methylated genomes of Arabidopsis1 and human2, demonstrates a strategy for sequencing the epigenomes of organisms such as insects that have low levels of methylation.
Nature Biotechnology 28, 516–520 (2010) http://www.nature.com/nbt/journal/v28/n5/abs/nbt.1626.html?lang=en#/
Insect Cell Biology 20. Cindr Interacts with Anillin to Control Cytokinesis in Drosophila melanogaster
Kaisa Haglund , Ioannis P. Nezis, Dafne Lemus, Caroline Grabbe, Jørgen Wesche, Knut Liestøl, Ivan Dikic, Ruth Palmer, Harald Stenmark Department of Biochemistry, Institute for Cancer Research, Oslo University Hospital, N-0310 Oslo, Norway Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Montebello, N-0310 Oslo, Norway Department of Molecular Biology, Umeå University, S-90187 Umeå, Sweden Department of Informatics, University of Oslo, N-0316 Oslo, Norway Institute of Biochemistry II, Frankfurt University Medical School, Theodor-Stein-Kai 7, D-60590 Frankfurt, Germany
Highlights Cindr is involved in complete and incomplete cytokinesis in Drosophila. Cindr and Anillin interact and colocalize at stable intercellular bridges. Binucleation after Cindr depletion suggests a role in bridge stabilization. Persistent intercellular bridges are present in the major Drosophila imaginal discs Summary Cytokinesis, the final step of cell division, conventionally proceeds to cell separation by abscission, or complete cytokinesis [1, 2,1, 2], but may in certain tissues be incomplete, yielding daughter cells that are interconnected in syncytia by stable intercellular bridges [3]. The mechanisms that determine complete versus incomplete cytokinesis are not known. Here we report a novel in vivo role of the Drosophila CD2AP/CIN85 ortholog Cindr in both complete and incomplete cytokinesis. We also show evidence for the presence of persistent intercellular bridges in the major larval imaginal Insect Frontiers, May 2010 Volume 2 Number 5 disc epithelia. During conventional division of both cultured and embryonic cells, Cindr localizes to cleavage furrows, intercellular bridges, and midbodies. Moreover, in cells undergoing incomplete cytokinesis in the female germline and the somatic ovarian follicle cell and larval imaginal disc epithelia, Cindr localizes to arrested cleavage furrows and stable intercellular bridges, respectively. In these structures, Cindr colocalizes with the essential cytokinesis regulator Anillin. We show that Cindr interacts with Anillin and that depletion of either Cindr or Anillin gives rise to binucleate cells and fewer intercellular bridges in vivo. We propose that Cindr and Anillin cooperate to promote intercellular bridge stability during incomplete cytokinesis in Drosophila melanogaster. Current Biology, Volume 20, Issue 10, 944-950, 06 May 2010 http://www.cell.com/current-biology/abstract/S0960-9822%2810%2900444-6
21. Scarface, a secreted serine protease-like protein, regulates polarized localization of laminin A at the basement membrane of the Drosophila embryo
Georgina Sorrosal1, Lidia Pérez1, Héctor Herranz1 & Marco Milán1,2 [email protected] Institute for Research in Biomedicine, Baldiri i Reixac 10, 08028 Barcelona, Spain Institució Catalana de Recerca i Estudis Avançats, Baldiri i Reixac 10, 08028 Barcelona, Spain
Cell–matrix interactions brought about by the activity of integrins and laminins maintain the polarized architecture of epithelia and mediate morphogenetic interactions between apposing tissues. Although the polarized localization of laminins at the basement membrane is a crucial step in these processes, little is known about how this polarized distribution is achieved. Here, in Drosophila, we analyse the role of the secreted serine protease-like protein Scarface in germ-band retraction and dorsal closure— morphogenetic processes that rely on the activity of integrins and laminins. We present evidence that scarface is regulated by c-Jun amino-terminal kinase and that scarface mutant embryos show defects in these morphogenetic processes. Anomalous accumulation of laminin A on the apical surface of epithelial cells was observed in these embryos before a loss of epithelial polarity was induced. We propose that Scarface has a key role in regulating the polarized localization of laminin A in this developmental context. EMBO reports (2010) 11, 373 - 379 http://www.nature.com/embor/journal/v11/n5/abs/embor201043.html
22. A distinctive role for focal adhesion proteins in three-dimensional cell motility
Stephanie I. Fraley1,2,6, Yunfeng Feng2,3,4,6, Ranjini Krishnamurthy1, Dong-Hwee Kim1,2, Alfredo Celedon1,5, Gregory D. Longmore2,3,4 & Denis Wirtz1,2 [email protected] [email protected] 1. Department of Chemical and Biomolecular Engineering, The Johns Hopkins University, Baltimore, Maryland 21218, USA. 2. Johns Hopkins Physical Sciences in Oncology Center, Johns Hopkins University, Baltimore, Maryland 21218, USA. 3. Departments of Medicine and Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110, USA. 4. Washington University BRIGHT Institute, Washington University School of Medicine, St. Louis, MO 63110, USA. 5. Department of Mechanical Engineering, Pontificia Universidad Católica de Chile, P.O. Box 306, Santiago, 6904411, Chile.
Focal adhesions are large multi-protein assemblies that form at the basal surface of cells on planar dishes, and that mediate cell signalling, force transduction and adhesion to the substratum. Although much is known about focal adhesion components in two- dimensional (2D) systems, their role in migrating cells in a more physiological three- dimensional (3D) matrix is largely unknown. Live-cell microscopy shows that for cells fully embedded in a 3D matrix, focal adhesion proteins, including vinculin, paxillin, talin, α-actinin, zyxin, VASP, FAK and p130Cas, do not form aggregates but are diffusely distributed throughout the cytoplasm. Despite the absence of detectable focal adhesions, focal adhesion proteins still modulate cell motility, but in a manner distinct from cells on Insect Frontiers, May 2010 Volume 2 Number 5 planar substrates. Rather, focal adhesion proteins in matrix-embedded cells regulate cell speed and persistence by affecting protrusion activity and matrix deformation, two processes that have no direct role in controlling 2D cell speed. This study shows that membrane protrusions constitute a critical motility/matrix-traction module that drives cell motility in a 3D matrix. Nature Cell Biology 12, 598 - 604 (2010) http://www.nature.com/ncb/journal/v12/n6/abs/ncb2062.html?lang=en
Insect Chemoreception 23. Behavioral insensitivity to DEET in Aedes aegypti is a genetically determined trait residing in changes in sensillum function
Nina M. Stanczyka,b, John F. Y. Brookfieldb, Rickard Ignellc, James G. Logana,1, and Linda M. [email protected] aCentre for Sustainable Pest and Disease Management, Biological Chemistry Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom; bSchool of Biology, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom; and cDivision of Chemical Ecology, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Box 102,230 53 Alnarp, Sweden
N,N-Diethyl-m-toluamide (DEET) is one of the most effective and commonly used mosquito repellents. However, during laboratory trials a small proportion of mosquitoes are still attracted by human odors despite the presence of DEET. In this study behavioral assays identified Aedes aegypti females that were insensitive to DEET, and the selection of either sensitive or insensitive groups of females with males of unknown sensitivity over several generations resulted in two populations with different proportions of insensitive females. Crossing experiments showed the “insensitivity” trait to be dominant. Electroantennography showed a reduced response to DEET in the selected insensitive line compared with the selected sensitive line, and single sensillum recordings identified DEET-sensitive sensilla that were nonresponders in the insensitive line. This study suggests that behavioral insensitivity to DEET in A. aegypti is a genetically determined dominant trait and resides in changes in sensillum function. PNAS May 11, 2010 vol. 107 no. 19 8575-8580 http://www.pnas.org/content/107/19/8575.abstract?etoc
24. Bombykol receptors in the silkworm moth and the fruit fly
Zainulabeuddin Syeda, Artyom Koppb, Deborah A. Kimbrellc, and Walter S. Leala,1 [email protected] Departments of aEntomology, Honorary Maeda-Duffey Laboratory, bEcology and Evolution, and cMolecular and Cellular Biology, University of California, Davis, CA 95616
Male moths are endowed with odorant receptors (ORs) to detect species-specific sex pheromones with remarkable sensitivity and selectivity. We serendipitously discovered that an endogenous OR in the fruit fly, Drosophila melanogaster, is highly sensitive to the sex pheromone of the silkworm moth, bombykol. Intriguingly, the fruit fly detectors are more sensitive than the receptors of the silkworm moth, although its ecological significance is unknown. By expression in the “empty neuron” system, we identified the fruit fly bombykol-sensitive OR as DmelOR7a (= DmOR7a). The profiles of this receptor in response to bombykol in the native sensilla (ab4) or expressed in the empty neuron system (ab3 sensilla) are indistinguishable. Both WT and transgenic flies responded with high sensitivity, in a dose-dependent manner, and with rapid signal termination. In contrast, the same empty neuron expressing the moth bombykol receptor, BmorOR1, demonstrated low sensitivity and slow signal inactivation. When expressed in the trichoid sensilla T1 of the fruit fly, the neuron housing BmorOR1 responded with sensitivity comparable to that of the native trichoid sensilla in the silkworm moth. By challenging the native bombykol receptor in the fruit fly with high doses of another odorant to which the receptor responds with the highest sensitivity, we demonstrate that slow signal Insect Frontiers, May 2010 Volume 2 Number 5 termination is induced by overdose of a stimulus. As opposed to the empty neuron system in the basiconic sensilla, the structural, biochemical, and/or biophysical features of the sensilla make the T1 trichoid system of the fly a better surrogate for the moth receptor. PNAS May 18, 2010 vol. 107 no. 20 9436-9439 http://www.pnas.org/content/107/20/9436.abstract?etoc
25. Post-eclosion odor experience modifies olfactory receptor neuron coding in Drosophila
Atulya Iyengara,1, Tuhin Subhra Chakrabortyb,1, Sarit Pati Goswamib, Chun-Fang Wua,c, and Obaid Siddiqib,2 aInterdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA 52242; bNational Centre for Biological Sciences, Bangalore 560065, India; and cDepartment of Biology, University of Iowa, Iowa City, IA 52242
Olfactory responses of Drosophila undergo pronounced changes after eclosion. The flies develop attraction to odors to which they are exposed and aversion to other odors. Behavioral adaptation is correlated with changes in the firing pattern of olfactory receptor neurons (ORNs). In this article, we present an information-theoretic analysis of the firing pattern of ORNs. Flies reared in a synthetic odorless medium were transferred after eclosion to three different media: (i) a synthetic medium relatively devoid of odor cues, (ii) synthetic medium infused with a single odorant, and (iii) complex cornmeal medium rich in odors. Recordings were made from an identified sensillum (type II), and the Jensen–Shannon divergence (DJS) was used to assess quantitatively the differences between ensemble spike responses to different odors. Analysis shows that prolonged exposure to ethyl acetate and several related esters increases sensitivity to these esters but does not improve the ability of the fly to distinguish between them. Flies exposed to cornmeal display varied sensitivity to these odorants and at the same time develop greater capacity to distinguish between odors. Deprivation of odor experience on an odorless synthetic medium leads to a loss of both sensitivity and acuity. Rich olfactory experience thus helps to shape the ORNs response and enhances its discriminative power. The experiments presented here demonstrate an experience-dependent adaptation at the level of the receptor neuron. PNAS May 25, 2010 vol. 107 no. 21 9855-9860 http://www.pnas.org/content/107/21/9855.abstract?etoc
Insect Development 26. Neuronal expression of Mgat1 rescues the shortened life span of Drosophila Mgat11 null mutants and increases life span
Mohan Sarkara, Konstantin G. Iliadib, Peter A. Leventisb, Harry Schachtera,c,1, and Gabrielle L. Boulianneb,d aProgram in Molecular Structure and Function, The Hospital for Sick Children, Toronto, ON, Canada M5G 1X8; bProgram in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto Medical Discovery Tower, Toronto, ON, Canada M5G 1L7; cDepartment of Biochemistry, University of Toronto, Toronto, ON, Canada M5S 1A8; and dDepartment of Molecular Genetics, University of Toronto, Toronto, ON, Canada M5S 1A8
The enzyme UDP-GlcNAc:α3-D-mannoside β1,2-N-acetylglucosaminyltransferase I (GnT1, encoded by Mgat1) controls the synthesis of paucimannose N-glycans in Drosophila. We have previously reported that null mutations in Drosophila Mgat1 are viable but exhibit defects in locomotion, brain abnormalities, and a severely reduced life span. Here, we show that knockdown of Mgat1 in the central nervous system (CNS) of wild-type flies decreases locomotor activity and life span. This phenotype is similar to that observed in Drosophila Mgat11 null mutants, demonstrating that Mgat1 is required in the CNS. We also found that neuronal expression of a wild-type Mgat1 transgene rescued the shortened life span of Mgat11 null mutants and resulted in a dramatic 135% increase in mean life span relative to genetically identical controls. Neuronal expression of a wild- type Mgat1 transgene in wild-type flies resulted in a modest 9% increase in mean life Insect Frontiers, May 2010 Volume 2 Number 5 span relative to genetically identical controls. In both Mgat11 null mutants and wild-type flies, neuronal expression of wild-type Mgat1 transgene resulted in a significant increase in GnT1 activity and resistance to oxidative stress. Whereas dietary restriction is not absolutely essential for the increased life span, it plays a role in the process. Interestingly, we observe a direct correlation between GnT1 activity and mean life span up to a maximum of ~136 days, showing that the ability of GnT1 activity to increase life span is limited. Altogether, these observations suggest that Mgat1-dependent N-glycosylation plays an important role in the control of Drosophila life span. PNAS May 25, 2010 vol. 107 no. 21 9677-9682 http://www.pnas.org/content/107/21/9677.abstract?etoc
Insect Ecology 27. A mathematical model of exposure of non-target Lepidoptera to Bt-maize pollen expressing Cry1Ab within Europe
J. N. Perry1,*, Y. Devos2, S. Arpaia3, D. Bartsch4, A. Gathmann4, R. S. Hails5, J. Kiss6, K. Lheureux2, B. Manachini7, S. Mestdagh2, G. Neemann8, F. Ortego9, J. Schiemann10 and J. B. Sweet11 [email protected] 1Oaklands Barn, Lug's Lane, Broome, Norfolk NR35 2HT, UK 2European Food Safety Authority (EFSA), GMO Unit, Largo Natale Palli 5/A, 43121 Parma, Italy 3National Agency for New Technologies, Energy and Environment (ENEA), Research Centre Trisaia, 75026 Rotondella, Italy 4Bundesamt für Verbraucherschutz und Lebensmittelsicherheit (BVL), Federal Office of Consumer Protection and Food Safety, Mauerstrasse 39-42, 10117 Berlin, Germany 5Centre for Ecology and Hydrology, Mansfield Road, Oxford OX1 3SR, UK 6Plant Protection Institute, Szent István University, Pater K. 1, 2100 Gödöllő, Hungary 7Animal Biology Department, University of Palermo, Via Archirafi, 18, 90123 Palermo, Italy 8Büro für Landschaftsökologie und Umweltstudien, Wiesenstraße 8, 37073 Göttingen, Germany 9Centro de Investigaciones Biológicas (CSIC), Departamento de Biología de Plantas, Laboratorio Interacción Planta-Insecto, C/Ramiro de Maeztu 9, 28040 Madrid, Spain 10Julius Kühn Institute, Federal Research Centre for Cultivated Plants (JKI), Institute for Biosafety of Genetically Modified Plants, Erwin- Baur-Strasse 27, 06484 Quedlinburg, Germany 11Sweet Environmental Consultants, 6 The Green, Willingham, Cambridge CB24 5JA, UK
Genetically modified (GM) maize MON810 expresses a Cry1Ab insecticidal protein, derived from Bacillus thuringiensis (Bt), toxic to lepidopteran target pests such as Ostrinia nubilalis. An environmental risk to non-target Lepidoptera from this GM crop is exposure to harmful amounts of Bt-containing pollen deposited on host plants in or near MON810 fields. An 11-parameter mathematical model analysed exposure of larvae of three non-target species: the butterflies Inachis io (L.), Vanessa atalanta (L.) and moth Plutella xylostella (L.), in 11 representative maize cultivation regions in four European countries. A mortality–dose relationship was integrated with a dose–distance relationship to estimate mortality both within the maize MON810 crop and within the field margin at varying distances from the crop edge. Mortality estimates were adjusted to allow for physical effects; the lack of temporal coincidence between the susceptible larval stage concerned and the period over which maize MON810 pollen is shed; and seven further parameters concerned with maize agronomy and host-plant ecology. Sublethal effects were estimated and allowance made for aggregated pollen deposition. Estimated environmental impact was low: in all regions, the calculated mortality rate for worst-case scenarios was less than one individual in every 1572 for the butterflies and one in 392 for the moth. Proc. R. Soc. B 7 May 2010 vol. 277 no. 1686 1417-1425 http://rspb.royalsocietypublishing.org/content/277/1686/1417.abstract?etoc
28. Induced niche shift as an anti-predator response for an endoparasitoid
Frédéric B. Muratori1,2,*, Sophie Borlee2 and Russell H. Messing2 [email protected] 1Unité d’écologie et biogéographie, Biodiversity Research Centre, Université de Louvain, 4 croix du sud, B-1348 Louvain-la-Neuve, Belgium 2Kauai Agricultural Research Center, University of Hawaii at Manoa, 7370 Kuamoo Road, Kapaa, HI 96746, USA
When two developmental stages do not share the same ecological niche, the control of the niche shift through a change in developmental timing, referred to as ‘heterokairy’, can provide an adaptive advantage for the individual (e.g. if mortality risk is higher in the first niche). For endoparasitic species that develop inside another (host) species, mortality of the host may directly induce mortality risk for the parasite. Thus, Insect Frontiers, May 2010 Volume 2 Number 5 endoparasitoid larvae should be selected for response to host predation. In this study, aphids previously parasitized by the endoparasitoid Endaphis fugitiva, Gagné and Muratori (Diptera: Cecidomyiidae), were experimentally exposed to increased mortality risks. Both simulated attack and actual predator attacks against aphid hosts induced early emergence of the parasitoid larvae. Parasitoid emergence from the aphids occurred several minutes before the predator finished feeding on the aphid, allowing enough time for the parasitoid larvae to avoid direct predation. Predator-induced emergence produced significantly smaller parasitoid larvae than controls, but, interestingly, no effect on Endaphis adult size was found. To our knowledge, this is the first evidence of induced emergence in an insect parasitoid, but we suggest that this mechanism might be at work in many other species where plasticity in development time allows the individual to perform an adaptive niche shift. Proc. R. Soc. B 22 May 2010 vol. 277 no. 1687 1475-1480 http://rspb.royalsocietypublishing.org/content/277/1687/1475.abstract
29. Host sanctions and pollinator cheating in the fig tree–fig wasp mutualism
K. Charlotte Jandér1,2,3,* and Edward Allen [email protected] 1Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA 2Smithsonian Tropical Research Institute, Unit 9100, PO Box 0948, DPO, AA 34002-9998, USA 3Department of Animal Ecology, Evolutionary Biology Centre, Uppsala University, 752 36 Uppsala, Sweden
Theory predicts that mutualisms should be vulnerable to invasion by cheaters, yet mutualistic interactions are both ancient and diverse. What prevents one partner from reaping the benefits of the interaction without paying the costs? Using field experiments and observations, we examined factors affecting mutualism stability in six fig tree–fig wasp species pairs. We experimentally compared the fitness of wasps that did or did not perform their most basic mutualistic service, pollination. We found host sanctions that reduced the fitness of non-pollinating wasps in all derived, actively pollinated fig species (where wasps expend time and energy pollinating), but not in the basal, passively pollinated fig species (where wasps do not). We further screened natural populations of pollinators for wasp individuals that did not carry pollen (‘cheaters’). Pollen-free wasps occurred only in actively pollinating wasp species, and their prevalence was negatively correlated with the sanction strength of their host species. Combined with previous studies, our findings suggest that (i) mutualisms can show coevolutionary dynamics analogous to those of ‘arms races’ in overtly antagonistic interactions; (ii) sanctions are critical for long-term mutualism stability when providing benefits to a host is costly, and (iii) there are general principles that help maintain cooperation both within and among species. Proc. R. Soc. B 22 May 2010 vol. 277 no. 1687 1481-1488 http://rspb.royalsocietypublishing.org/content/277/1687/1481.abstract
30. Mirid Bug Outbreaks in Multiple Crops Correlated with Wide-Scale Adoption of Bt Cotton in China
Yanhui Lu,1 Kongming Wu,1,* Yuying Jiang,2 Bing Xia,2 Ping Li,2 Hongqiang Feng,1 Kris A. G. Wyckhuys,1, Yuyuan Guo1 [email protected] 1 State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, People’s Republic of China. 2 National Agro-Technical Extension and Service Center, Beijing 100026, People’s Republic of China.
Long-term ecological effects of transgenic Bacillus thuringiensis (Bt) crops on nontarget pests have received limited attention, more so in diverse small holder–based cropping systems of the developing world. Field trials conducted over 10 years in northern China show that mirid bugs (Heteroptera: Miridae) have progressively increased population sizes and acquired pest status in cotton and multiple other crops, in association with a regional increase in Bt cotton adoption. More specifically, our analyses show that Bt cotton has become a source of mirid bugs and that their population increases are related Insect Frontiers, May 2010 Volume 2 Number 5 to drops in insecticide use in this crop. Hence, alterations of pest management regimes in Bt cotton could be responsible for the appearance and subsequent spread of nontarget pests at an agro-landscape level. Science 28 May 2010:Vol. 328. no. 5982, pp. 1151 – 1154 http://www.sciencemag.org/cgi/content/abstract/328/5982/1151?sa_campaign=Email/to c/28-May-2010/10.1126/science.1187881
Insect Evolution 31. MATERNAL EFFECTS, BUT NO GOOD OR COMPATIBLE GENES FOR SPERM COMPETITIVENESS IN AUSTRALIAN CRICKETS
Damian K. Dowling 1,2,3 , Magdalena Nystrand 1,2,4 , and Leigh W. Simmons 2,5 1 School of Biological Sciences, Monash University, Clayton, 3800, Victoria, Australia 2 Centre for Evolutionary Biology, School of Animal Biology (M092), University of Western Australia, Crawley, 6009, Western Australia, Australia 3 E-mail: [email protected] 4 E-mail: [email protected] 5 E-mail: [email protected]
Explanations for the evolution of polyandry often center on the idea that females garner genetic benefits for their offspring by mating multiply. Furthermore, postcopulatory processes are thought to be fundamental to enabling polyandrous females to screen for genetic quality. Much attention has focused on the potential for polyandrous females to accrue such benefits via a sexy- or good-sperm mechanism, whereby additive variation exists among males in sperm competitiveness. Likewise, attention has focused on an alternative model, in which offspring quality (in this context, the sperm competitiveness of sons) hinges on an interaction between parental haplotypes (genetic compatibility). Sperm competitiveness that is contingent on parental compatibility will exhibit nonadditive genetic variation. We tested these models in the Australian cricket, Teleogryllus oceanicus, using a design that allowed us to partition additive, nonadditive genetic, and parental variance for sperm competitiveness. We found an absence of additive and nonadditive genetic variance in this species, challenging the direct relevance of either model to the evolution of sperm competitiveness in particular, and polyandry in general. Instead, we found maternal effects that were possibly sex-linked or cytoplasmically linked. We also found effects of focal male age on sperm competitiveness, with small increments in age conferring more competitive sperm. Evolution 2010 Volume 64 Issue 5, Pages 1257 - 1266 http://www3.interscience.wiley.com/journal/123192458/abstract
32. Z LINKAGE OF FEMALE PROMISCUITY GENES IN THE MOTH UTETHEISA ORNATRIX: SUPPORT FOR THE SEXY-SPERM HYPOTHESIS?
Vikram K. Iyengar 1,2 and Hudson K. Reeve 3,4 1 Department of Biology, Villanova University, 800 Lancaster Avenue, Villanova, Pennsylvania 19085 2 E-mail: [email protected] 3 Department of Neurobiology and Behavior, Cornell University, Ithaca, New York 14853 4 E-mail: [email protected]
Female preference genes for large males in the highly promiscuous moth Utetheisa ornatrix (Lepidoptera: Arctiidae) have previously been shown to be mostly Z-linked, in accordance with the hypothesis that ZZ–ZW sex chromosome systems should facilitate Fisherian sexual selection. We determined the heritability of both female and male promiscuity in the highly promiscuous moth U. ornatrix (Lepidoptera: Arctiidae) through parent–offspring and grandparent–offspring regression analyses. Our data show that male promiscuity is not sex-limited and either autosomal or sex-linked whereas female promiscuity is primarily determined by sex-limited, Z-linked genes. These data are consistent with the "sexy-sperm hypothesis," which posits that multiple-mating and sperm competitiveness coevolve through a Fisherian-like process in which female promiscuity is a kind of mate choice in which sperm-competitiveness is the trait favored in males. Such a Fisherian process should also be more potent when female preferences are Z-linked and sex-limited than when autosomal or not limited. Evolution 2010 Volume 64 Issue 5, Pages 1267 - 1272 Insect Frontiers, May 2010 Volume 2 Number 5 http://www3.interscience.wiley.com/journal/123192456/abstract
33. THE ROLES OF LIFE-HISTORY SELECTION AND SEXUAL SELECTION IN THE ADAPTIVE EVOLUTION OF MATING BEHAVIOR IN A BEETLE
Alexei A. Maklakov 1,2,3 , Luis Cayetano, Robert C. Brooks 1 , and Russell Bonduriansky 1 1 Evolution & Ecology Research Centre and School of Biological, Earth and Environmental Sciences, The University of New South Wales, Kensington, Sydney 2052, Australia 2 E-mail: [email protected]
Although there is continuing debate about whether sexual selection promotes or impedes adaptation to novel environments, the role of mating behavior in such adaptation remains largely unexplored. We investigated the evolution of mating behavior (latency to mating, mating probability and duration) in replicate populations of seed beetles Callosobruchus maculatus subjected to selection on life-history ("Young" vs. "Old" reproduction) under contrasting regimes of sexual selection ("Monogamy" vs. "Polygamy"). Life-history selection is predicted to favor delayed mating in "Old" females, but sexual conflict under polygamy can potentially retard adaptive life-history evolution. We found that life-history selection yielded the predicted changes in mating behavior, but sexual selection regime had no net effect. In within-line crosses, populations selected for late reproduction showed equally reduced early-life mating probability regardless of mating system. In between-line crosses, however, the effect of life-history selection on early-life mating probability was stronger in polygamous lines than in monogamous ones. Thus, although mating system influenced male–female coevolution, removal of sexual selection did not affect the adaptive evolution of mating behavior. Importantly, our study shows that the interaction between sexual selection and life-history selection can result in either increased or decreased reproductive divergence depending on the ecological context. Evolution 2010 Volume 64 Issue 5, Pages 1273 - 1282 http://www3.interscience.wiley.com/journal/123188423/abstract
34. SEX RATIO DRIVE PROMOTES SEXUAL CONFLICT AND SEXUAL COEVOLUTION IN THE FLY DROSOPHILA PSEUDOOBSCURA
Tom A. R. Price 1 , Zenobia Lewis 2 , Damian T. Smith 1 , Gregory D. D. Hurst 3 , and Nina Wedell 1,4 1 School of Biosciences, University of Exeter, Cornwall Campus. Penryn TR10 9EZ, United Kingdom 2 School of Environmental Science, Okayama University, Okayama 700-8530, Japan 3 School of Biological Sciences, University of Liverpool, Liverpool L69 7ZB, United Kingdom 4 E-mail: [email protected]
Selfish genetic elements occur in all living organisms and often cause reduced fertility and sperm competitive ability in males. In the fruit fly Drosophila pseudoobscura, the presence of a sex-ratio distorting X-chromosome meiotic driver Sex Ratio (SR) has been shown to promote the evolution of increased female remating rates in laboratory populations. This is favored because it promotes sperm competition, which decreases the risk to females of producing highly female-biased broods and to their offspring of inheriting the selfish gene. Here, we show that non-SR males in these SR populations evolved an increased ability to suppress female remating in response to the higher female remating rates, indicating male–female coevolution. This occurred even though SR was rare in the populations. This was further supported by a correlation between females' remating propensity and males' ability to suppress female remating across populations. Thus SR can generate sexual conflict over female remating rate between females and the noncarrier males that make up the majority of the males, promoting evolution of increased ability of males to suppress female remating. Evolution 2010 Volume 64 Issue 5, Pages 1504 – 1509 http://www3.interscience.wiley.com/journal/122685685/abstract
35. Sexual conflict and the gender load: correlated evolution between population fitness and sexual dimorphism in seed beetles Insect Frontiers, May 2010 Volume 2 Number 5
Göran Arnqvist1,* and Midori Tuda2 [email protected] 1Evolutionary Biology Centre, Department of Ecology and Evolution, Animal Ecology, Uppsala University, Uppsala, Sweden 2Institute of Biological Control, Faculty of Agriculture, Kyushu University, Fukuoka, Japan
Although males and females share much of the same genome, selection is often distinct in the two sexes. Sexually antagonistic loci will in theory cause a gender load in populations, because sex-specific selection on a given trait in one sex will compromise the adaptive evolution of the same trait in the other sex. However, it is currently not clear whether such intralocus sexual conflict (ISC) represents a transient evolutionary state, where conflict is rapidly resolved by the evolution of sexual dimorphism (SD), or whether it is a more chronic impediment to adaptation. All else being equal, ISC should manifest itself as correlated evolution between population fitness and SD in traits expressed in both sexes. However, comparative tests of this prediction are problematic and have been unfeasible. Here, we assess the effects of ISC by comparing fitness and SD across distinct laboratory populations of seed beetles that should be well adapted to a shared environment. We show that SD in juvenile development time, a key life-history trait with a history of sexually antagonistic selection in this model system, is positively related to fitness. This effect is due to a correlated evolution between population fitness and development time that is positive in females but negative in males. Loosening the genetic bind between the sexes has evidently allowed the sexes to approach their distinct adaptive peaks.
Proc. R. Soc. B 7 May 2010 vol. 277 no. 1686 1345-1352 http://rspb.royalsocietypublishing.org/content/277/1686/1345.abstract?etoc
Insect Genetics 36. Nonallelic Gene Conversion in the Genus Drosophila
Claudio Casola*,1, Carrie L. Ganote and Matthew W. Hahn*, [email protected] * Department of Biology, Indiana University, Bloomington, Indiana 47405 and School of Informatics and Computing, Indiana University, Bloomington, Indiana 47405
Nonallelic gene conversion has been proposed as a major force in homogenizing the sequences of paralogous genes. In this work, we investigate the extent and characteristics of gene conversion among gene families in nine species of the genus Drosophila. We carried out a genome-wide study of 2855 gene families (including 17,742 genes) and determined that conversion events involved 2628 genes. The proportion of converted genes ranged across species from 1 to 9% when paralogs of all ages were included. Although higher levels of gene conversion were found among young gene duplicates, at most 1–2% of the coding sequences of these duplicates were affected by conversion. Using a second approach relying on gene family size changes and gene- tree/species-tree reconciliation methods, we estimate that only 1–15% of gene trees are misled by gene conversion, depending on the lineage considered. Several features of paralogous genes correlate with gene conversion, such as intra-/interchromosomal location, level of nucleotide divergence, and GC content, although we found no definitive evidence for biased substitution patterns. After considering species-specific differences in the age and distance between paralogs, we found a highly significant difference in the amount of gene conversion among species. In particular, members of the melanogaster group showed the lowest proportion of converted genes. Our data therefore suggest underlying differences in the mechanistic basis of gene conversion among species. Genetics, Vol. 185, 95-103, May 2010 http://www.genetics.org/cgi/content/abstract/185/1/95
37. Hearing in Drosophila Requires TilB, a Conserved Protein Associated With Ciliary Motility
Ryan G. Kavlie*, Maurice J. Kernan and Daniel F. Eberl*,1 [email protected] Insect Frontiers, May 2010 Volume 2 Number 5 * Interdisciplinary Graduate Program in Genetics and Department of Biology, University of Iowa, Iowa City, Iowa 52242 and Department of Neurobiology and Behavior, State University of New York, Stony Brook, New York 11974
Cilia were present in the earliest eukaryotic ancestor and underlie many biological processes ranging from cell motility and propulsion of extracellular fluids to sensory physiology. We investigated the contribution of the touch insensitive larva B (tilB) gene to cilia function in Drosophila melanogaster. Mutants of tilB exhibit dysfunction in sperm flagella and ciliated dendrites of chordotonal organs that mediate hearing and larval touch sensitivity. Mutant sperm axonemes as well as sensory neuron dendrites of Johnston's organ, the fly's auditory organ, lack dynein arms. Through deficiency mapping and sequencing candidate genes, we identified tilB mutations in the annotated gene CG14620. A genomic CG14620 transgene rescued deafness and male sterility of tilB mutants. TilB is a 395-amino-acid protein with a conserved N-terminal leucine-rich repeat region at residues 16–164 and a coiled-coil domain at residues 171–191. A tilB-Gal4 transgene driving fluorescently tagged TilB proteins elicits cytoplasmic expression in embryonic chordotonal organs, in Johnston's organ, and in sperm flagella. TilB does not appear to affect tubulin polyglutamylation or polyglycylation. The phenotypes and expression of tilB indicate function in cilia construction or maintenance, but not in intraflagellar transport. This is also consistent with phylogenetic association of tilB homologs with presence of genes encoding axonemal dynein arm components. Further elucidation of tilB functional mechanisms will provide greater understanding of cilia function and will facilitate understanding ciliary diseases. Genetics, Vol. 185, 177-188, May 2010, http://www.genetics.org/cgi/content/abstract/185/1/177
38. Activation of Sterol Regulatory Element Binding Proteins in the Absence of Scap in Drosophila melanogaster
Krista A. Matthews1, Cafer Ozdemir and Robert B. Rawson2 [email protected] Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9046
The escort factor Scap is essential in mammalian cells for regulated activation of sterol regulatory element binding proteins (SREBPs). SREBPs are membrane-bound transcription factors. Cells lacking Scap cannot activate SREBP. They are therefore deficient in the transcription of numerous genes involved in lipid synthesis and uptake; they cannot survive in the absence of exogenous lipid. Here we report that, in contrast to mammalian cells, Drosophila completely lacking dscap are viable. Flies lacking dscap emerge at 70% of the expected rate and readily survive as homozygous stocks. These animals continue to cleave dSREBP in some tissues. Transcription of dSREBP target genes in dscap mutant larvae is reduced compared to wild type. It is greater than in mutants lacking dSREBP and remains responsive to dietary lipids in dscap mutants. Flies lacking dscap do not require the caspase Drice to activate dSREBP. This contrasts with ds2p mutants. ds2p encodes a protease that releases the transcription factor domain of dSREBP from the membrane. Larvae doubly mutant for dscap and ds2p exhibit phenotypes similar to those of ds2p single mutants. Thus, dScap and dS2P, essential components of the SREBP activation machinery in mammalian cells, are dispensable in Drosophila owing to different compensatory mechanisms. Genetics, Vol. 185, 189-198, May 2010, http://www.genetics.org/cgi/content/abstract/185/1/189
39. The Steroid Molting Hormone Ecdysone Regulates Sleep in Adult Drosophila melanogaster
Hiroshi Ishimoto* and Toshihiro Kitamoto*, ,1 [email protected] * Department of Anesthesia, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242 and Interdisciplinary Programs in Genetics and Neuroscience, University of Iowa, Iowa City, Iowa 52242
Insect Frontiers, May 2010 Volume 2 Number 5 Ecdysone is the major steroid hormone in insects and plays essential roles in coordinating developmental transitions such as larval molting and metamorphosis through its active metabolite 20-hydroxyecdysone (20E). Although ecdysone is present throughout life in both males and females, its functions in adult physiology remain largely unknown. In this study we demonstrate that ecdysone-mediated signaling in the adult is intimately involved in transitions between the physiological states of sleep and wakefulness. First, administering 20E to adult Drosophila melanogaster promoted sleep in a dose-dependent manner, and it did so primarily by altering the length of sleep and wake bouts without affecting waking activity. Second, mutants for ecdysone synthesis displayed the "short- sleep phenotype," and this was alleviated by administering 20E at the adult stage. Third, mutants for nuclear ecdysone receptors showed reduced sleep, and conditional overexpression of wild-type ecdysone receptors in the adult mushroom bodies resulted in an isoform-specific increase in sleep. Finally, endogenous ecdysone levels increased after sleep deprivation, and mutants defective for ecdysone signaling displayed little sleep rebound, suggesting that ecdysone is involved in homeostatic sleep regulation. In light of the recent finding that lethargus—a period at larval-stage transitions in the nematode worm Caenorhabditis elegans—is a sleep-like state, our results suggest that sleep is functionally and mechanistically linked to a genetically programmed, quiescent behavioral state during development. Genetics, Vol. 185, 269-281, May 2010, http://www.genetics.org/cgi/content/abstract/185/1/269
40. Muller's Ratchet and the Degeneration of the Drosophila miranda Neo-Y Chromosome
Vera B. Kaiser and Brian Charlesworth1 [email protected] Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3JT, United Kingdom
Since its formation about 1.75 million years ago, the Drosophila miranda neo-Y chromosome has undergone a rapid process of degeneration, having lost approximately half of the genes that it originally contained. Using estimates of mutation rates and selection coefficients for loss-of-function mutations, we show that the high rate of accumulation of these mutations can largely be explained by Muller's ratchet, the process of stochastic loss of the least-loaded mutational class from a finite, nonrecombining population. We show that selection at nonsynonymous coding sites can accelerate the process of gene loss and that this effect varies with the number of genes still present on the degenerating neo-Y chromosome. Genetics, Vol. 185, 339-348, May 2010, http://www.genetics.org/cgi/content/abstract/185/1/339
41. Sexual isolation of male moths explained by a single pheromone response QTL containing four receptor genes
Fred Goulda,1, Marie Estocka,2, N. Kirk Hillierb,3, Bekah Powella, Astrid T. Groota,4, Catherine M. Warda,5, Jennifer L. Emersona, Coby Schala, and Neil J. Vickersb [email protected] aDepartment of Entomology and W. M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, NC 27695; and bDepartment of Biology, University of Utah, Salt Lake City, UT 84112
Long distance sexual communication in moths has fascinated biologists because of the complex, precise female pheromone signals and the extreme sensitivity of males to specific pheromone molecules. Progress has been made in identifying some genes involved in female pheromone production and in male response. However, we have lacked information on the genetic changes involved in evolutionary diversification of these mate-finding mechanisms that is critical to understanding speciation in moths and other taxa. We used a combined quantitative trait locus (QTL) and candidate gene approach to determine the genetic architecture of sexual isolation in males of two congeneric moths, Heliothis subflexa and Heliothis virescens. We report behavioral and Insect Frontiers, May 2010 Volume 2 Number 5 neurophysiological evidence that differential male responses to three female-produced chemicals (Z9-14:Ald, Z9-16:Ald, Z11-16:OAc) that maintain sexual isolation of these species are all controlled by a single QTL containing at least four odorant receptor genes. It is not surprising that pheromone receptor differences could control H. subflexa and H. virescens responses to Z9-16:Ald and Z9-14:Ald, respectively. However, central rather than peripheral level control over the positive and negative responses of H. subflexa and H. virescens to Z11-16:OAc had been expected. Tight linkage of these receptor genes indicates that mutations altering male response to complex blends could be maintained in linkage disequilibrium and could affect the speciation process. Other candidate genes such as those coding for pheromone binding proteins did not map to this QTL, but there was some genetic evidence of a QTL for response to Z11-16:OH associated with a sensory neuron membrane protein gene. PNAS May 11, 2010 vol. 107 no. 19 8660-8665 http://www.pnas.org/content/107/19/8660.abstract?etoc
Insect Learning 42. Electric Shock-Induced Associative Olfactory Learning in Drosophila Larvae
Dennis Pauls *, Johanna E.R. Pfitzenmaier *, Rebecca Krebs-Wheaton, Mareike Selcho, Reinhard F. Stocker and Andreas S. Thum [email protected] Department of Biology, University of Fribourg, CH-1700 Fribourg, Switzerland
Associative plasticity is a basic essential attribute of nervous systems. As shown by numerous reports, Drosophila is able to establish simple forms of appetitive and aversive olfactory associations at both larval and adult stages. Whereas most adult studies on aversive learning employed electric shock as a negative reinforcer, larval paradigms essentially utilized gustatory stimuli to create negative associations, a discrepancy that limits the comparison of data. To overcome this drawback, we critically revisited larval odor–electric shock conditioning. First, we show that lithium chloride (LiCl), which was used in all previous larval electric shock paradigms, is not required per se in larval odor– electric shock learning. This is of considerable practical advantage because beside its peculiar effects LiCl is attractive to larvae at low concentration that renders comparative learning studies on genetically manipulated larvae complicated. Second, we confirm that in both a 2-odor reciprocal and a 1-odor nonreciprocal conditioning regimen, larvae are able to associate an odor with electric shock. In the latter experiments, initial learning scores reach an asymptote after 5 training trials, and aversive memory is still detectable after 60 min. Our experiments provide a comprehensive basis for future comparisons of larval olfactory conditioning reinforced by different modalities, for studies aimed at analyzing odor–electric shock learning in the larva and the adult, and for investigations of the cellular and molecular substrate of aversive olfactory learning in the simple Drosophila model. Chemical Senses 2010 35(4):335-346; doi:10.1093/chemse/bjq023’ http://chemse.oxfordjournals.org/cgi/content/abstract/35/4/335
Insect Molecular Biology 43. The miRNA machinery targets Mei-P26 and regulates Myc protein levels in the Drosophila wing
Héctor Herranz1, Xin Hong2,3, Lidia Pérez1, Ana Ferreira1, Daniel Olivieri1, Stephen M Cohen2,3 and Marco Milán1,[email protected] Cell and Developmental Biology Programme, Institute for Research in Biomedicine, Barcelona, Spain Temasek Life Sciences Laboratory, National University of Singapore, Singapore Department of Biological Sciences, National University of Singapore, Singapore ICREA, Barcelona, Spain
MicroRNAs (miRNAs) have been implicated in cell-cycle regulation and in some cases shown to have a role in tissue growth control. Depletion of miRNAs was found to have an effect on tissue growth rates in the wing primordium of Drosophila, a highly proliferative Insect Frontiers, May 2010 Volume 2 Number 5 epithelium. Dicer-1 (Dcr-1) is a double-stranded RNAseIII essential for miRNA biogenesis. Adult cells lacking dcr-1, or with reduced dcr-1 activity, were smaller than normal cells and gave rise to smaller wings. dcr-1 mutant cells showed evidence of being susceptible to competition by faster growing cells in vivo and the miRNA machinery was shown to promote G1–S transition. We present evidence that Dcr-1 acts by regulating the TRIM- NHL protein Mei-P26, which in turn regulates dMyc protein levels. Mei-P26 is a direct target of miRNAs, including the growth-promoting bantam miRNA. Thus, regulation of tissue growth by the miRNA pathway involves a double repression mechanism to control dMyc protein levels in a highly proliferative and growing epithelium. The EMBO Journal (2010) 29, 1688 - 1698 http://www.nature.com/emboj/journal/v29/n10/abs/emboj201069a.html
44. The molecular basis for water taste in Drosophila
Peter Cameron, Makoto Hiroi, John Ngai & Kristin Scott Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, 16 Barker Hall Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute and Functional Genomics Laboratory, 142 Life Sciences Addition
The detection of water and the regulation of water intake are essential for animals to maintain proper osmotic homeostasis1. Drosophila and other insects have gustatory sensory neurons that mediate the recognition of external water sources2, 3, 4, but little is known about the underlying molecular mechanism for water taste detection. Here we identify a member of the degenerin/epithelial sodium channel family5, PPK28, as an osmosensitive ion channel that mediates the cellular and behavioural response to water. We use molecular, cellular, calcium imaging and electrophysiological approaches to show that ppk28 is expressed in water-sensing neurons, and that loss of ppk28 abolishes water sensitivity. Moreover, ectopic expression of ppk28 confers water sensitivity to bitter- sensing gustatory neurons in the fly and sensitivity to hypo-osmotic solutions when expressed in heterologous cells. These studies link an osmosensitive ion channel to water taste detection and drinking behaviour, providing the framework for examining the molecular basis for water detection in other animals. Nature 465,91–95 (06 May 2010) http://www.nature.com/nature/journal/v465/n7294/abs/nature09011.html?lang=en#/aff il-auth
Insect Molecular Ecology 45. Wolbachia modulates Chikungunya replication in Aedes albopictus
L. MOUSSON*, E. MARTIN*, K. ZOUACHE‡, Y. MADEC†, P. MAVINGUI‡ and A. B. FAILLOUX* [email protected] *Institut Pasteur, Génétique moléculaire des Bunyavirus, 25-28 rue du Dr Roux, F-75724 Paris Cedex 15, France , †Institut Pasteur, Unité de Recherche et d'Expertise Epidémiologie des Maladies Emergentes, 25-28 rue du Dr Roux, F-75724 Paris Cedex 15, France , ‡Université Lyon, F-69022, Lyon, France, Université de Lyon 1, Villeurbanne, CNRS, UMR5557, Ecologie Microbienne, Lyon, France
The Aedes albopictus mosquito has been involved as the principal vector of recent major outbreaks due to the chikungunya virus (CHIKV). The species is naturally infected by two strains of Wolbachia (wAlbA and wAlbB). Wolbachia infections are thought to have spread by manipulating the reproduction of their hosts; cytoplasmic incompatibility is the mechanism used by Wolbachia to invade natural populations of many insects including Ae. albopictus. Here, we report a study on the effects of removing Wolbachia from Ae. albopictus on CHIKV replication and examine the consequences of CHIKV infection on some life-history traits (survival and reproduction) of Wolbachia-free Ae. albopictus. We found that Wolbachia-free mosquitoes maintained a highly heterogeneous CHIKV replication compared to Wolbachia-infected individuals. In Wolbachia-infected Ae. albopictus, the regular increase of CHIKV followed by a steady viral load from day 4 post- infection onwards was concomitant with a decline in Wolbachia density. This profile was also detected when examining the two key organs for viral transmission, the midgut and Insect Frontiers, May 2010 Volume 2 Number 5 the salivary glands. Moreover, Wolbachia-free Ae. albopictus was not altered in life- history traits such as survival, oviposition and hatching characteristics whether infected or not with CHIKV. We found that Wolbachia is not essential for viral replication, its presence could lead to optimize replication from day 4 post-infection onwards, coinciding with a decrease in Wolbachia density. Wolbachia may regulate viral replication in Ae. albopictus, with consequences on survival and reproduction. Molecular Ecology 2010 Volume 19 Issue 9, Pages 1953 - 1964 http://www3.interscience.wiley.com/journal/123327351/abstract?CRETRY=1&SRETRY=0
46. Differential introgression causes genealogical discordance in host races of Acrocercops transecta (Insecta: Lepidoptera)
ISSEI OHSHIMA*† and KAZUNORI YOSHIZAWA* [email protected] *Systematic Entomology, Department of Ecology and Systematics, Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan , †Division of Evolutionary Biology, National Institute for Basic Biology, Okazaki 444-8585, Japan
Recently diverged populations often exhibit incomplete reproductive isolation, with a low level of gene flow continuing between populations. Previous studies have shown that, even under a low level of gene flow, genetic divergence between populations can proceed at the loci governing local adaptation and reproductive isolation but not at other neutral loci. A leaf-mining moth, Acrocercops transecta, consists of Juglans- and Lyonia- associated host races. The two host races differ in host preferences of ovipositing females and in larval adaptation to host plants but mate readily in the laboratory, producing fertile hybrids. The Juglans and Lyonia races are often sympatric in the wild, implying that gene introgression could occur in nature between the two host races. We tested this hypothesis by combining phylogenetic analyses with coalescent simulations, focusing on mitochondrial genes (COI and ND5) and the nuclear Tpi, Per and Ldh genes located on the Z-chromosome. The mitochondrial genes clearly distinguished the Lyonia race from the Juglnas race, whereas the Tpi, Per and Ldh genealogies did not reflect the two host races. Coalescent simulations indicated gene flow at the three Z-linked genes in both directions, whereas there was no introgression in the mitochondrial genes. The lack of introgression in mitochondrial genes suggests that female host preference is the primary force leading to the bifurcation of maternally inherited loci. Thus, the results show that a low level of gene flow coupled with the inflexible female host preference differentiates histories of divergence between maternally and biparentally inherited genes in this host race system. Molecular Ecology 2010 Volume 19 Issue 10, Pages 2106 - 2119 http://www3.interscience.wiley.com/journal/123337844/abstract
47. Population genetic structure of two primary parasitoids of Spodoptera frugiperda (Lepidoptera), Chelonus insularis and Campoletis sonorensis (Hymenoptera): to what extent is the host plant important?
VIOLAINE JOURDIE*†, NADIR ALVAREZ*, JAIME MOLINA-OCHOA‡, TREVOR WILLIAMS§, DAVID BERGVINSON¶, BETTY BENREY*, TED C. J. TURLINGS* and PIERRE FRANCK** [email protected] *Université de Neuchâtel, Institut de Biologie, Case Postale 158, 2009 Neuchâtel, Switzerland , †University of Manchester, Faculty of Life Sciences, Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK , ‡Universidad de Colima, Facultad de Ciencias Biológicas y Agropecuarias, Apartado postal no. 36, Campus Tecomán, Colima 28100, Colima, México , §ECOSUR, Apdo Postal 36, Tapachula 30700, Chiapas, México , ¶CIMMYT Apdo. Postal 6-641, 06600 Mexico, D.F., Mexico , **INRA, UR1115 Plantes & Systèmes de culture Horticoles, AgroParc, Domaine St-Paul, 84914 AVIGNON Cedex 9, France
Plant chemistry can strongly influence interactions between herbivores and their natural enemies, either by providing volatile compounds that serve as foraging cues for parasitoids or predators, or by affecting the quality of herbivores as hosts or prey. Through these effects plants may influence parasitoid population genetic structure. We tested for a possible specialization on specific crop plants in Chelonus insularis and Campoletis sonorensis, two primary parasitoids of the fall armyworm, Spodoptera Insect Frontiers, May 2010 Volume 2 Number 5 frugiperda. Throughout Mexico, S. frugiperda larvae were collected from their main host plants, maize and sorghum and parasitoids that emerged from the larvae were used for subsequent comparison by molecular analysis. Genetic variation at eight and 11 microsatellites were respectively assayed for C. insularis and C. sonorensis to examine isolation by distance, host plant and regional effects. Kinship analyses were also performed to assess female migration among host-plants. The analyses showed considerable within population variation and revealed a significant regional effect. No effect of host plant on population structure of either of the two parasitoid species was found. Isolation by distance was observed at the individual level, but not at the population level. Kinship analyses revealed significantly more genetically related—or kin—individuals on the same plant species than on different plant species, suggesting that locally, mothers preferentially stay on the same plant species. Although the standard population genetics parameters showed no effect of plant species on population structure, the kinship analyses revealed that mothers exhibit plant species fidelity, which may speed up divergence if adaptation were to occur. Molecular Ecology 2010 Volume 19 Issue 10, Pages 2168 - 2179 http://www3.interscience.wiley.com/journal/123342770/abstract
48. Host-associated genetic differentiation in a seed parasitic weevil Rhinusa antirrhini (Coleptera: Curculionidae) revealed by mitochondrial and nuclear sequence data
GERARDO HERNÁNDEZ-VERA*, MILANA MITROVIƆ, JELENA JOVIƆ, IVO TOŠEVSKI‡, ROBERTO CALDARA§, ANDRE GASSMANN‡ and BRENT C. EMERSON* [email protected] *Centre for Ecology, Evolution and Conservation, School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK , †Institute for Plant Protection and Environment, Banatska 33, Zemun, Serbia , ‡CABI Europe, Switzerland, 1 Rue des Grillons, 2800 Delémont, Switzerland , §via Lorenteggio 37, 20146 Milan, Italy
Plant feeding insects and the plants they feed upon represent an ecological association that is thought to be a key factor for the diversification of many plant feeding insects, through differential adaptation to different plant selective pressures. While a number of studies have investigated diversification of plant feeding insects above the species level, relatively less attention has been given to patterns of diversification within species, particularly those that also require plants for oviposition and subsequent larval development. In the case of plant feeding insects that also require plant tissues for the completion of their reproductive cycle through larval development, the divergent selective pressure not only acts on adults, but on the full life history of the insect. Here we focus attention on Rhinusa antirrhini (Curculionidae), a species of weevil broadly distributed across Europe that both feeds on, and oviposits and develops within, species of the plant genus Linaria (Plantaginaceae). Using a combination of mtDNA (COII) and nuclear DNA (EF1-α) sequencing and copulation experiments we assess evidence for host associated genetic differentiation within R. antirrhini. We find substantial genetic variation within this species that is best explained by ecological specialisation on different host plant taxa. This genetic differentiation is most pronounced in the mtDNA marker, with patterns of genetic variation at the nuclear marker suggesting incomplete lineage sorting and/or gene flow between different host plant forms of R. antirrhini, whose origin is estimated to date to the mid-Pliocene (3.77 Mya; 2.91–4.80 Mya). Molecular Ecology 2010 Volume 19 Issue 11, Pages 2286 - 2300 http://www3.interscience.wiley.com/journal/123416012/abstract
49. Inbreeding in a natural population of the gregarious parasitoid wasp Cotesia glomerata
J. ELIAS, S. DORN and D. MAZZI [email protected] ETH Zurich, Institute of Plant, Animal and Agroecosystem Sciences, Applied Entomology, Schmelzbergstrasse 9, CH – 8092 Zurich, Switzerland
Insect Frontiers, May 2010 Volume 2 Number 5 Inbreeding occurs in numerous animal and plant species. In haplodiploid hymenopterans with the widespread single locus complementary sex determination, the frequency of diploid males, which are produced at the expense of females, is increased under inbreeding. Diploid males in species of bees, ants and wasps are typically either unviable or effectively sterile and thus impose a severe genetic load on populations. However, a recent study indicated that diploid males can be reproductive in the gregarious parasitoid wasp Cotesia glomerata, effectively reducing the diploid male load. To understand the role of inbreeding as a potential selective pressure towards the evolution of diploid male fertility, we genotyped specimens collected in the field at four locations using microsatellite markers to estimate the ratio of sibling matings under natural conditions. Results show that more than half of all matings involved siblings. We argue that the frequent occurrence of inbreeding has driven the evolution of diploid male fertility. Molecular Ecology 2010 Volume 19 Issue 11, Pages 2336 - 2345 http://www3.interscience.wiley.com/journal/123416011/abstract
Insect Morphology 50. Female germline stem cell niches of earwigs are structurally simple and different from those of Drosophila melanogaster
Waclaw Tworzydlo 1, Malgorzata Kloc 2 3, Szczepan M. Bilinski 1 *[email protected] 1Department of Systematic Zoology, Institute of Zoology, Jagiellonian University, Krakow, Poland 2The Methodist Hospital, The Methodist Hospital Research Institute, Houston, Texas 3The University of Texas M. D. Anderson Cancer Center, Houston, Texas
Stem cells function in niches, which consist of somatic cells that control the stem cells' self-renewal, proliferation, and differentiation. Drosophila ovary germline niche consists of the terminal filament (TF) cells, cap cells, and escort stem cells; signaling from the TF cells and the cap cells is essential for maintenance of germline stem cells (GSCs). Here, we show that in the earwig Opisthocosmia silvestris, the female GSC niche is morphologically simple and consist of the TF cells and several structurally uniform escort cells. The most posterior cell of the TF (the basal cell of the TF) differs from remaining TF cells and is separated from the anterior region of the germarium by the processes of the escort cells, and consequently, does not contact the GSCs directly. We also show that between somatic cells of earwig niche argosome-like vesicles and cytoneme-like extensions are present. J. Morphol., 2010. © 2009 Wiley-Liss, Inc. Journal of Morphology 2010 Volume 271 Issue 5, Pages 634 - 640 http://www3.interscience.wiley.com/journal/123222114/abstract
Insect Neuroethology 51. Auditory-based defence against gleaning bats in neotropical katydids (Orthoptera: Tettigoniidae)
Hannah M. ter Hofstede1 , Elisabeth K. V. Kalko2, 3 and James H. Fullard4 School of Biological Sciences, University of Bristol, Woodland Road, Bristol, BS8 1UG, UK Institute of Experimental Ecology, University of Ulm, Ulm, Germany Smithsonian Tropical Research Institute, Balboa, Republic of Panama Department of Biology, University of Toronto Mississauga, Mississauga, ON, Canada
Neotropical katydids (Orthoptera: Tettigoniidae) are preyed on by gleaning bats, which are known to use male calling songs to locate them. At least one katydid species has been reported to stop singing in response to bat echolocation calls. To investigate the relationship between this behavioural defence and ecological and sensory factors, we surveyed calling song characteristics, song cessation in response to the echolocation calls of a sympatric gleaning bat (Trachops cirrhosus), and T-cell responses (an auditory interneuron sensitive to ultrasound) in five katydid species from Panamá. The two katydid species that stopped singing in response to bat calls (Balboa tibialis and Ischnomela gracilis, Pseudophyllinae) also had the highest T-cell spike number and rate in response to these stimuli. The third pseudophylline species (Docidocercus gigliotosi) did not reliably cease singing and had low T-cell spiking activity. Neoconocephalus affinis Insect Frontiers, May 2010 Volume 2 Number 5 (Copiphorinae) produced continuous calling song, possibly preventing males from hearing the bat during singing, and did not show a behavioural response despite high T-cell activity in response to bat calls. Steirodon rufolineatum (Phaneropterinae) did not cease singing and differed in T-cell activity compared to the other species. T-cell function might not be conserved in katydids, and evidence for this idea is discussed. Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology Volume 196, Number 5 / May, 2010 349-358 http://www.springerlink.com/content/c8436816240755x3/
52. Mutation of the Drosophila vesicular GABA transporter disrupts visual figure detection
Hao Fei1,*, , Dawnis M. Chow2, , Audrey Chen3, Rafael Romero-Calderón1, Wei S. Ong3, Larry C. Ackerson1, Nigel T. Maidment1, Julie H. Simpson4, Mark A. Frye2 and David E. Krantz1, [email protected] 1 Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA 2 Howard Hughes Medical Institute, Department of Integrative Biology and Physiology, UCLA, Los Angeles, CA 90095, USA 3 Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA 4 Howard Hughes Medical Institute Janelia Farm Research Campus, Ashburn, VA 20147, USA
The role of gamma amino butyric acid (GABA) release and inhibitory neurotransmission in regulating most behaviors remains unclear. The vesicular GABA transporter (VGAT) is required for the storage of GABA in synaptic vesicles and provides a potentially useful probe for inhibitory circuits. However, specific pharmacologic agents for VGAT are not available, and VGAT knockout mice are embryonically lethal, thus precluding behavioral studies. We have identified the Drosophila ortholog of the vesicular GABA transporter gene (which we refer to as dVGAT), immunocytologically mapped dVGAT protein expression in the larva and adult and characterized a dVGATminos mutant allele. dVGAT is embryonically lethal and we do not detect residual dVGAT expression, suggesting that it is either a strong hypomorph or a null. To investigate the function of VGAT and GABA signaling in adult visual flight behavior, we have selectively rescued the dVGAT mutant during development. We show that reduced GABA release does not compromise the active optomotor control of wide-field pattern motion. Conversely, reduced dVGAT expression disrupts normal object tracking and figure–ground discrimination. These results demonstrate that visual behaviors are segregated by the level of GABA signaling in flies, and more generally establish dVGAT as a model to study the contribution of GABA release to other complex behaviors. Journal of Experimental Biology 213, 1717-1730 (2010) http://jeb.biologists.org/cgi/content/abstract/213/10/1717
Insect Neuroscience 53. Response competition associated with right–left antennal asymmetries of new and old olfactory memory traces in honeybees
Elisa Frasnellia, , , Giorgio Vallortigaraa and Lesley J. Rogersb a CiMeC, Centre for Mind/Brain Sciences, University of Trento, Corso Bettini 31, 38068 Rovereto, Italy b Centre for Neuroscience and Animal Behaviour, University of New England, Armidale, NSW 2351, Australia
Lateralized recall of olfactory memory in honeybees was tested, following conditioning of the proboscis extension reflex (PER), at 1 or 6 h after training. After training with lemon (+)/vanilla (−) or cineol (+)/eugenol (−) recall at 1 h was better when the odour was presented to the right side of the bee than when it was presented to the left side. In contrast, recall at 6 h was better when the odour was presented to the left than to the right side. This confirmed previous evidence of shorter-term recall via the right antenna and long-term memory recall via the left antenna. However, when trained with either a Insect Frontiers, May 2010 Volume 2 Number 5 familiar appetitive odour (rose) as a negative stimulus, or with a naturally aversive odour (isoamyl acetate, IAA) as a positive stimulus, bees showed suppression of the response from both the right and the left side at 1 h after training (likely due to retroactive inhibition) and at 6 h responded to both odours on both sides. We argued that at 6 h, when access to memory has completed the shift from the right to the left side, memory of these familiar odours in the left side of the brain would be present as both positive (rose)/negative (IAA) (as a result of long-term memory either biologically encoded or acquired well before testing) and negative (rose)/positive (IAA) (as a result of the long- term memory of training) stimuli, thus producing response competition. As a direct test of this hypothesis, bees were first trained with unfamiliar lemon (+)/vanilla (−) and then (16 h later) re-trained with vanilla (+)/lemon (−); as predicted, 6 h after re-training bees responded to both odours on both the left and right side. Behavioural Brain Research Volume 209, Issue 1, 1 May 2010, Pages 36-41 http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6SYP-4Y646H3- 8&_user=8538702&_coverDate=05%2F01%2F2010&_rdoc=1&_fmt=high&_orig=search&_sort=d&_docanchor=&view=c&_acct=C000050221&_vers ion=1&_urlVersion=0&_userid=8538702&md5=aa0317ec359dd95cd7d0324eadd7a6ca
54. Neural Activity in the Central Complex of the Insect Brain Is Linked to Locomotor Changes
John A. Bender , Alan J. Pollack, Roy E. Ritzmann Department of Biology, Case Western Reserve University, Cleveland, OH 44106-7080, USA Corresponding author
Highlights Neural units in the central complex alter their firing rate during walking. Changes in firing are highly correlated with moment-to-moment changes in step rate. In some neural units, changes in firing rate occur before changes in step rate. Electrical stimulation of these areas could elicit increased step frequencies Summary Animals negotiating complex natural terrain must consider cues around them and alter movement parameters accordingly [1, 2,1, 2]. In the arthropod brain, the central complex (CC) receives bilateral sensory relays and sits immediately upstream of premotor areas, suggesting that it may be involved in the context-dependent control of behavior [3]. In previous studies, CC neurons in various insects responded to visual, chemical, and mechanical stimuli [4,5,6,7], and genetic or physical lesions affected locomotor behaviors [8,9,10,11]. Additionally, electrical stimulation of the CC led to malformed chirping movements by crickets [12], and pharmacological stimulation evoked stridulation in grasshoppers [13], but no more precise relationship has been documented between neural activity in the CC and movements in a behaving animal. We performed tetrode recordings from the CC of cockroaches walking in place on a slippery surface. Neural activity in the CC was strongly correlated with, and in some cases predictive of, stepping frequency. Electrical stimulation of these areas also evoked or modified walking. Many of the same neural units responded to tactile antennal stimulation while the animal was standing still but became unresponsive during walking. Therefore, these CC units are unlikely to be reporting only sensory signals, but their activity may be directing changes in locomotion based on sensory inputs. Current Biology, Volume 20, Issue 10, 921-926, 06 May 2010 http://www.cell.com/current-biology/abstract/S0960-9822%2810%2900380-5
55. Visual experience and age affect synaptic organization in the mushroom bodies of the desert ant Cataglyphis fortis
Sara Mae Stieb 1, Thomas Sebastian Muenz 1, Rüdiger Wehner 2, Wolfgang Rössler 1 * [email protected] 1Department of Behavioral Physiology and Sociobiology, Biozentrum, University of Würzburg, Germany 2Brain Research Institute, University of Zürich, Switzerland
Desert ants of the genus Cataglyphis undergo an age-related polyethism from interior workers involved in brood care and food processing to short-lived outdoor foragers with remarkable visual navigation capabilities. The quick transition from dark to light suggests that visual centers in the ant's brain express a high degree of plasticity. To investigate Insect Frontiers, May 2010 Volume 2 Number 5 structural synaptic plasticity in the mushroom bodies (MBs) - sensory integration centers supposed to be involved in learning and memory - we immunolabeled and quantified pre- and postsynaptic profiles of synaptic complexes (microglomeruli, MG) in the visual (collar) and olfactory (lip) input regions of the MB calyx. The results show that a volume increase of the MB calyx during behavioral transition is associated with a decrease in MG numbers in the collar and, less pronounced, in the lip. Analysis of tubulin-positive profiles indicates that presynaptic pruning of projection neurons and dendritic expansion in intrinsic Kenyon cells are involved. Light-exposure of dark-reared ants of different age classes revealed similar effects. The results indicate that this structural synaptic plasticity in the MB calyx is primarily driven by visual experience rather than by an internal program. This is supported by the fact that dark-reared ants age-matched to foragers had MG numbers comparable to those of interior workers. Ants aged artificially for up to 1 year expressed a similar plasticity. These results suggest that the high degree of neuronal plasticity in visual input regions of the MB calyx may be an important factor related to behavior transitions associated with division of labor. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 70: 408-423, 2010 Developmental Neurobiology 2010 Volume 70 Issue 6, Pages 408 - 423 http://www3.interscience.wiley.com/journal/123271725/abstract
56. The Amiloride-Sensitive Epithelial Na+ Channel PPK28 Is Essential for Drosophila Gustatory Water Reception
Zijing Chen,1,2 Qingxiu Wang,1 and Zuoren Wang1 [email protected] 1Institute of Neuroscience, State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences and 2Graduate School, Chinese Academy of Sciences, Shanghai 200031, China
Water sensation is a specific taste modality in the fruit fly. Water-induced hypoosmolarity activates specific gustatory receptor neurons; however, the molecular identity of the putative osmolarity sensor in these neurons remains unknown. We found that amiloride and its analogs specifically antagonized the response of water gustatory receptor neurons and the behavior of flies toward water stimulation. Deletion of the gene that encodes the amiloride-sensitive PPK28 channel, a DEG/eNaC (degenerin/epithelial sodium channel) family member, abolished the water-induced activity of water gustatory receptor neurons and greatly diminished the behavioral response of flies to water. Ectopic expression of the PPK28 channel in the bitter cells within the intermediate-type sensilla renders these sensilla responsive to water stimuli. Thus, the amiloride-sensitive PPK28 channel may serve as the osmolarity sensor for gustatory water reception in the fruit fly. The Journal of Neuroscience, May 5, 2010, 30(18):6247-6252 http://www.jneurosci.org/cgi/content/abstract/30/18/6247 57. Long-Term Memory Leads to Synaptic Reorganization in the Mushroom Bodies: A Memory Trace in the Insect Brain?
Benoît Hourcade,1 Thomas S. Muenz,2 Jean-Christophe Sandoz,1 Wolfgang Rössler,2 and Jean-Marc Devaud1 [email protected] 1Research Centre on Animal Cognition, Centre National de la Recherche Scientifique–Université Paul- Sabatier, Unité Mixte de Recherche 5169, 31062 Toulouse cedex 04, France, and 2Department of Behavioral Physiology and Sociobiology, Biozentrum, University of Würzburg, D-97074 Würzburg, Germany
The insect mushroom bodies (MBs) are paired brain centers which, like the mammalian hippocampus, have a prominent function in learning and memory. Despite convergent evidence for their crucial role in the formation and storage of associative memories, little is known about the mechanisms underlying such storage. In mammals and other species, the consolidation of stable memories is accompanied by structural plasticity involving variations in synapse number and/or size. Here, we address the question of whether the formation of olfactory long-term memory (LTM) could be associated with changes in the synaptic architecture of the MB networks. For this, we took advantage of the modular architecture of the honeybee MB neuropil, where synaptic contacts between olfactory Insect Frontiers, May 2010 Volume 2 Number 5 input and MB neurons are segregated into discrete units (microglomeruli) which can be easily visualized and counted. We show that the density in microglomeruli increases as a specific olfactory LTM is formed, while the volume of the neuropil remains constant. Such variation is reproducible and is clearly correlated with memory consolidation, as it requires gene transcription. Thus stable structural synaptic rearrangements, including the growth of new synapses, seem to be a common property of insect and mammalian brain networks involved in the storage of stable memory traces. The Journal of Neuroscience, May 5, 2010, 30(18):6461-6465; http://www.jneurosci.org/cgi/content/abstract/30/18/6461
58. Calcium Activates a Chloride Conductance Likely Involved in Olfactory Receptor Neuron Repolarization in the Moth Spodoptera littoralis
Adeline Pézier, * Marta Grauso, * Adrien Acquistapace, Christelle Monsempes, Jean-Pierre Rospars, and Philippe Lucas [email protected] Unité Mixte de Recherche 1272 Physiologie de l'Insecte, Signalisation et Communication, Institut National de la Recherche Agronomique, F-78000 Versailles, France
The response of insect olfactory receptor neurons (ORNs) to odorants involves the opening of Ca2+-permeable channels, generating an increase in intracellular Ca2+ concentration. Here, we studied the downstream effect of this Ca2+ rise in cultured ORNs of the moth Spodoptera littoralis. Intracellular dialysis of Ca2+ from the patch pipette in whole-cell patch-clamp configuration activated a conductance with a K1/2 of 2.8 µM. Intracellular and extracellular anionic and cationic substitutions demonstrated that Cl– – – – carries this current. The anion permeability sequence I > NO > Br > Cl > CH3SO >> gluconate– of the Ca2+-activated Cl– channel suggests a weak electrical field pore of the channel. The Ca2+-activated current partly inactivated over time and did not depend on protein kinase C (PKC) and CaMKII activity or on calmodulin. Application of Cl– channel blockers, flufenamic acid, 5-nitro-2-(3-phenylpropylamino) benzoic acid, or niflumic acid reversibly blocked the Ca2+-activated current. In addition, lowering Cl– concentration in the sensillar lymph bathing the ORN outer dendrites caused a significant delay in pheromone response termination in vivo. The present work identifies a new Cl– conductance activated by Ca2+ in insect ORNs presumably required for ORN repolarization. The Journal of Neuroscience, May 5, 2010, 30(18):6323-6333; http://www.jneurosci.org/cgi/content/abstract/30/18/6323
59. Axonal Degeneration Is Regulated by the Apoptotic Machinery or a NAD+- Sensitive Pathway i n Insects and Mammals
Zohar Schoenmann,1 Efrat Assa-Kunik,2 Sheila Tiomny,1 Adi Minis,1 Liat Haklai-Topper,1 Eli Arama,2 and Avraham Yaron1 [email protected] [email protected] Departments of 1Biological Chemistry and 2Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
Selective degeneration of neuronal projections and neurite pruning are critical for establishment and maintenance of functional neural circuits in both insects and mammals. However, the molecular mechanisms that govern developmental neurite pruning versus injury-induced neurite degeneration are still mostly unclear. Here, we show that the effector caspases 6 and 3 are both expressed within axons and that, on trophic deprivation, they exhibit distinct modes of activation. Surprisingly, inhibition of caspases is not sufficient for axonal protection and a parallel modulation of a NAD+-sensitive pathway is required. The proapoptotic protein BAX is a key element in both pathways as its genetic ablation protected sensory axons against developmental degeneration both in vitro and in vivo. Last, we demonstrate that both pathways are also involved in developmental dendritic pruning in Drosophila. More specifically, the mouse WldS (Wallerian degeneration slow) protein, which is mainly composed of the full-length sequence of the NAD+ biosynthetic Nmnat1 enzyme, can suppress dendritic pruning in C4da (class IV dendritic arborization) sensory neurons in parallel to the fly effector Insect Frontiers, May 2010 Volume 2 Number 5 caspases. These findings indicate that two distinct autodestruction pathways act separately or in concert to regulate developmental neurite pruning. The Journal of Neuroscience, May 5, 2010, 30(18):6375-6386; http://www.jneurosci.org/cgi/content/abstract/30/18/6375
60. Sialyltransferase Regulates Nervous System Function in Drosophila
Elena Repnikova,1 * Kate Koles,1 * Michiko Nakamura,1 Jared Pitts,1 Haiwen Li,1 Apoorva Ambavane,1 Mark J. Zoran,2 and Vladislav M. Panin1 [email protected] 1Departments of Biochemistry and Biophysics and 2Biology, Texas A&M University, College Station, Texas 77843
In vertebrates, sialylated glycans participate in a wide range of biological processes and affect the development and function of the nervous system. While the complexity of glycosylation and the functional redundancy among sialyltransferases provide obstacles for revealing biological roles of sialylation in mammals, Drosophila possesses a sole vertebrate-type sialyltransferase, Drosophila sialyltransferase (DSiaT), with significant homology to its mammalian counterparts, suggesting that Drosophila could be a suitable model to investigate the function of sialylation. To explore this possibility and investigate the role of sialylation in Drosophila, we inactivated DSiaT in vivo by gene targeting and analyzed phenotypes of DSiaT mutants using a combination of behavioral, immunolabeling, electrophysiological, and pharmacological approaches. Our experiments demonstrated that DSiaT expression is restricted to a subset of CNS neurons throughout development. We found that DSiaT mutations result in significantly decreased life span, locomotor abnormalities, temperature-sensitive paralysis, and defects of neuromuscular junctions. Our results indicate that DSiaT regulates neuronal excitability and affects the function of a voltage-gated sodium channel. Finally, we showed that sialyltransferase activity is required for DSiaT function in vivo, which suggests that DSiaT mutant phenotypes result from a defect in sialylation of N-glycans. This work provided the first evidence that sialylation has an important biological function in protostomes, while also revealing a novel, nervous system-specific function of 2,6-sialylation. Thus, our data shed light on one of the most ancient functions of sialic acids in metazoan organisms and suggest a possibility that this function is evolutionarily conserved between flies and mammals. The Journal of Neuroscience, May 5, 2010, 30(18):6466-6476; http://www.jneurosci.org/cgi/content/abstract/30/18/6466
61. Light-Mediated TIM Degradation within Drosophila Pacemaker Neurons (s-LNvs) Is Neither Necessary nor Sufficient for Delay Zone Phase Shifts
Chih-Hang Anthony Tang1, Erica Hinteregger1, 2, Yuhua Shang1 and Michael Rosbash1, , 1 Howard Hughes Medical Institute, National Center for Behavioral Genomics and Department of Biology, Brandeis University, Waltham, MA 02454, USA
Circadian systems are entrained and phase shifted by light. In Drosophila, the model of light-mediated phase shifting begins with photon capture by CRYPTOCHROME (CRY) followed by rapid TIMELESS (TIM) degradation. In this study, we focused on phase delays and assayed TIM degradation within individual brain clock neurons in response to light pulses in the early night. Surprisingly, there was no detectable change in TIM staining intensity within the eight pacemaker s-LNvs. This indicates that TIM degradation within s-LNvs is not necessary for phase delays, and similar assays in other genotypes indicate that it is also not sufficient. In contrast, more dorsal circadian neurons appear light-sensitive in the early night. Because CRY is still necessary within the s-LNvs for phase shifting, the results challenge the canonical cell-autonomous molecular model and raise the question of how the pacemaker neuron transcription-translation clock is reset by light in the early night. Highlights ► TIM degradation within s-LNvs is neither necessary nor sufficient for phase delays ► CRY within s-LNvs is necessary for phase delays ► Dorsal circadian neurons are light-sensitive in the early night ► Circadian phase shifting is a network property Insect Frontiers, May 2010 Volume 2 Number 5 Neuron Volume 66, Issue 3, 13 May 2010, Pages 378-385 http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WSS-502FPVC- 7&_user=10&_coverDate=05%2F13%2F2010&_rdoc=1&_fmt=high&_orig=search&_sort=d&_docanchor=&view=c&_acct=C000050221&_version=1 &_urlVersion=0&_userid=10&md5=67ff3ceb6c05b745cf385bd7b6ba7230
62. Drosophila TRPA1 channel mediates chemical avoidance in gustatory receptor neurons
Sang Hoon Kima,1, Youngseok Leea,1, Bradley Akitakea, Owen M. Woodwardb, William B. Gugginob, and Craig Montella,2 aDepartments of Biological Chemistry and Neuroscience, Center for Sensory Biology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205; and bDepartment of Physiology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
Mammalian sweet, bitter, and umami taste is mediated by a single transduction pathway that includes a phospholipase C (PLC)β and one cation channel, TRPM5. However, in insects such as the fruit fly, Drosophila melanogaster, it is unclear whether different tastants, such as bitter compounds, are sensed in gustatory receptor neurons (GRNs) through one or multiple ion channels, as the cation channels required in insect GRNs are unknown. Here, we set out to explore additional sensory roles for the Drosophila TRPA1 channel, which was known to function in thermosensation. We found that TRPA1 was expressed in GRNs that respond to aversive compounds. Elimination of TRPA1 had no impact on the responses to nearly all bitter compounds tested, including caffeine, quinine, and strychnine. Rather, we found that TRPA1 was required in a subset of avoidance GRNs for the behavioral and electrophysiological responses to aristolochic acid. TRPA1 did not appear to be activated or inhibited directly by aristolochic acid. We found that elimination of the same PLC that leads to activation of TRPA1 in thermosensory neurons was also required in the TRPA1-expressing GRNs for avoiding aristolochic acid. Given that mammalian TRPA1 is required for responding to noxious chemicals, many of which cause pain and injury, our analysis underscores the evolutionarily conserved role for TRPA1 channels in chemical avoidance. PNAS May 4, 2010 vol. 107 no. 18 8440-8445 http://www.pnas.org/content/107/18/8440.abstract?etoc
Insect review 63. Short-term memories in Drosophila are governed by general and specific genetic systems
Troy Zars1 Division of Biological Sciences, University of Missouri, Columbia, Missouri 65211, USA
In a dynamic environment, there is an adaptive value in the ability of animals to acquire and express memories. That both simple and complex animals can learn is therefore not surprising. How animals have solved this problem genetically and anatomically probably lies somewhere in a range between a single molecular/anatomical mechanism that applies to all situations and a specialized mechanism for each learning situation. With an intermediate level of nervous system complexity, the fruit fly Drosophila has both general and specific resources to support different short-term memories. Some biochemical/cellular mechanisms are common between learning situations, indicating that flies do not have a dedicated system for each learning context. The opposite possible extreme does not apply to Drosophila either. Specialization in some biochemical and anatomical terms suggests that there is not a single learning mechanism that applies to all conditions. The distributed basis of learning in Drosophila implies that these systems were independently selected. Learn. Mem. 2010. 17: 246-251 http://learnmem.cshlp.org/content/17/5/246.abstract
64. Nature versus nurture in social insect caste differentiation
Tanja Schwander1, 4, , Nathan Lo2, Madeleine Beekman2, Benjamin P. Oldroyd2 and Laurent Keller3 Insect Frontiers, May 2010 Volume 2 Number 5 1 Simon Fraser University, Biological Sciences, 8888 University Drive, Burnaby V5A 1S6, Canada 2 Behaviour and Genetics of Social Insects Laboratory, School of Biological Sciences A12, University of Sydney, Sydney, NSW 2006, Australia 3 University of Lausanne, Biophore, 1015 Lausanne, Switzerland
Recent evidence for genetic effects on royal and worker caste differentiation from diverse social insect taxa has put an end to the view that these phenotypes stem solely from a developmental switch controlled by environmental factors. Instead, the relative influences of genotypic and environmental effects on caste vary among species, ranging from largely environmentally controlled phenotypes to almost purely genetic systems. Disentangling the selective forces that generate variation for caste predisposition will require characterizing the genetic mechanisms underlying this variation, and identifying particular life-history strategies and kin structures associated with strong genetic effects on caste. Trends in Ecology & Evolution Volume 25, Issue 5, May 2010, Pages 275-282 http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VJ1-4Y7X4HC- 1&_user=10&_coverDate=05%2F31%2F2010&_rdoc=1&_fmt=high&_orig=search&_sort=d&_docanchor=&view=c&_acct=C000050221&_version=1 &_urlVersion=0&_userid=10&md5=26c41a69adc60374ed828e936aa686a6
Edited by Xin-Cheng Zhao 2010-06-13