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Complex Genotype by Environment interactions and changing genetic architectures across thermal environments in the Australian field cricket, Teleogryllus oceanicus
Magdalena Nystrand, Damian K Dowling, Leigh W Simmons
BMC Evolutionary Biology , 2011, DOI: 10.1186/1471-2148-11-222
Abstract: We used a full diallel breeding design to screen for complex genotype-environment interactions, and genetic architectures underlying key morphological traits, across two thermal environments (the lab standard 27°C, and the cooler 23°C) in the Australian field cricket, Teleogryllus oceanicus. In males, complex three-way interactions between sire and dam parental haplotypes and the rearing environment accounted for up to 23 per cent of the scaled phenotypic variance in the traits we measured (body mass, pronotum width and testes mass), and each trait harboured significant additive genetic variance in the standard temperature (27°C) only. In females, these three-way interactions were less important, with interactions between the paternal haplotype and rearing environment accounting for about ten per cent of the phenotypic variance (in body mass, pronotum width and ovary mass). Of the female traits measured, only ovary mass for crickets reared at the cooler temperature (23°C), exhibited significant levels of additive genetic variance.Our results show that the genetics underlying phenotypic expression can be complex, context-dependent and different in each of the sexes. We discuss the implications of these results, particularly in terms of the evolutionary processes that hinge on good and compatible genes models.There has been a recent surge in interest among evolutionary biologists in elucidating the genetic determinants of phenotypic quality [1,2]. This has been driven in part by researchers working in the field of sexual selection, who have sought to address whether females might acquire indirect genetic benefits for their offspring by mating with males of particular genotypes. As such, much attention has focussed on two groups of models that centre on the genetic benefits that might be gained from exhibiting mate discrimination: good genes and genetic compatibility [3-12]. In short, good genes models are based on the premise that genetic variation, acting additively,
Sexual Signaling and Immune Function in the Black Field Cricket Teleogryllus commodus  [PDF]
Jean M. Drayton, Matthew D. Hall, John Hunt, Michael D. Jennions
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0039631
Abstract: The immunocompetence handicap hypothesis predicts that male sexual trait expression should be positively correlated with immunocompetence. Here we investigate if immune function in the cricket, Teleogryllus commodus, is related to specific individual components of male sexual signals, as well as to certain multivariate combinations of these components that females most strongly prefer. Male T. commodus produce both advertisement and courtship calls prior to mating. We measured fine-scale structural parameters of both call types and also recorded nightly advertisement calling effort. We then measured two standard indices of immune function: lysozyme-like activity of the haemolymph and haemocyte counts. We found a weak, positive relationship between advertisement calling effort and lysozyme-like activity. There was, however, little evidence that individual structural call components or the net multivariate attractiveness of either call type signalled immune function. The relationships between immunity and sexual signaling did not differ between inbred and outbred males. Our data suggest that it is unlikely that females assess overall male immune function using male calls.
Calling song and phonotactic selectivity in the field cricket Teleogryllus emma (Orthoptera: Gryllidae)  [cached]
Soojin Jang,Hyon-Gyong An,Yikweon Jang
Journal of Ecology and Field Biology , 2010,
Abstract: Males of the field cricket Teleogryllus emma produce calling songs that are attractive to receptive females. The callingsongs of T. emma consist of two components, the long chirp that is composed of up to 12 single pulses, followed by avariable number of short chirps. Based on the analysis of coefficient of variation (CV), temporal characters of the longchirp were less variable than those of the short chirps in male calling songs. To test for phonotactic selectivity of females,we conducted a single-stimulus playback experiment in which five stimuli (standard, long chirp only, long chirp augmented,short chirps only, and short chirps augmented) were used. The standard stimulus included both long and shortchirps whose characteristics were derived from the calling songs of field populations. Results of the playback experimentshowed that female crickets oriented more frequently toward the stimuli that included the long chirp (standard, longchirp only, and long chirp augmented stimuli) than toward the stimuli lacking the long chirp (short chirps only and shortchirps augmented stimuli), indicating that the long chirp in the calling songs was required to elicit positive phonotaxis inthe female crickets. The result of CV analysis of the male calling songs and the findings of the female phonotaxis experimentsuggested that the long chirp of calling songs may play a role in species recognition in T. emma.
Seminal Fluid Affects Sperm Viability in a Cricket  [PDF]
Leigh W. Simmons,Maxine Beveridge
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0017975
Abstract: Recent studies have suggested that males may vary the quality of their ejaculates in response to sperm competition, although the mechanisms by which they do so remain unclear. The viability of sperm is an important aspect of ejaculate quality that determines competitive fertilization success in the field cricket Teleogryllus oceanicus. Using in vitro mixtures of sperm and seminal fluid from pairs of male crickets, we show that seminal fluid can affect the viability of sperm in this species. We found that males who invest greatly in the viability of their own sperm can enhance the viability of rival sperm, providing the opportunity for males to exploit the investments in sperm competition made by their rivals. Transitive effects of seminal fluids across the ejaculates of different males are expected to have important implications for the dynamics of male investments in sperm competition.
Cuticular hydrocarbons of Chagas disease vectors in Mexico
Juárez, M Patricia;Carlson, David A;Salazar Schettino, Paz María;Mijailovsky, Sergio;Rojas, Gloria;
Memórias do Instituto Oswaldo Cruz , 2002, DOI: 10.1590/S0074-02762002000600012
Abstract: capillary gas-liquid chromatography was used to analyse the cuticular hydrocarbons of three triatomine species, triatoma dimidiata, t. barberi and dipetalogaster maxima, domestic vectors of chagas disease in mexico. mixtures of saturated hydrocarbons of straight and methyl-branched chains were characteristic of the three species, but quantitatively different. major methylbranched components mostly corresponded to different saturated isomers of monomethyl, dimethyl and trimethyl branched hydrocarbons ranging from 29 to 39 carbon backbones. sex-dependant, quantitative differences in certain hydrocarbons were apparent in t. dimidiata.
Cuticular hydrocarbons of Chagas disease vectors in Mexico  [cached]
Juárez M Patricia,Carlson David A,Salazar Schettino Paz María,Mijailovsky Sergio
Memórias do Instituto Oswaldo Cruz , 2002,
Abstract: Capillary gas-liquid chromatography was used to analyse the cuticular hydrocarbons of three triatomine species, Triatoma dimidiata, T. barberi and Dipetalogaster maxima, domestic vectors of Chagas disease in Mexico. Mixtures of saturated hydrocarbons of straight and methyl-branched chains were characteristic of the three species, but quantitatively different. Major methylbranched components mostly corresponded to different saturated isomers of monomethyl, dimethyl and trimethyl branched hydrocarbons ranging from 29 to 39 carbon backbones. Sex-dependant, quantitative differences in certain hydrocarbons were apparent in T. dimidiata.
Drosophila Cuticular Hydrocarbons Revisited: Mating Status Alters Cuticular Profiles  [PDF]
Claude Everaerts,Jean-Pierre Farine,Matthew Cobb,Jean-Fran?ois Ferveur
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0009607
Abstract: Most living organisms use pheromones for inter-individual communication. In Drosophila melanogaster flies, several pheromones perceived either by contact/at a short distance (cuticular hydrocarbons, CHs), or at a longer distance (cis-vaccenyl acetate, cVA), affect courtship and mating behaviours. However, it has not previously been possible to precisely identify all potential pheromonal compounds and simultaneously monitor their variation on a time scale. To overcome this limitation, we combined Solid Phase Micro-Extraction with gas-chromatography coupled with mass-spectrometry. This allowed us (i) to identify 59 cuticular compounds, including 17 new CHs; (ii) to precisely quantify the amount of each compound that could be detected by another fly, and (iii) to measure the variation of these substances as a function of aging and mating. Sex-specific variation appeared with age, while mating affected cuticular compounds in both sexes with three possible patterns: variation was (i) reciprocal in the two sexes, suggesting a passive mechanical transfer during mating, (ii) parallel in both sexes, such as for cVA which strikingly appeared during mating, or (iii) unilateral, presumably as a result of sexual interaction. We provide a complete reassessment of all Drosophila CHs and suggest that the chemical conversation between male and female flies is far more complex than is generally accepted. We conclude that focusing on individual compounds will not provide a satisfactory understanding of the evolution and function of chemical communication in Drosophila.
Dietary Effects on Cuticular Hydrocarbons and Sexual Attractiveness in Drosophila  [PDF]
Tatyana Y. Fedina, Tsung-Han Kuo, Klaus Dreisewerd, Herman A. Dierick, Joanne Y. Yew, Scott D. Pletcher
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0049799
Abstract: Dietary composition is known to have profound effects on many aspects of animal physiology, including lifespan, general health, and reproductive potential. We have previously shown that aging and insulin signaling significantly influence the composition and sexual attractiveness of Drosophila melanogaster female cuticular hydrocarbons (CHCs), some of which are known to be sex pheromones. Because diet is intimately linked to aging and to the activity of nutrient-sensing pathways, we asked how diet affects female CHCs and attractiveness. Here we report consistent and significant effects of diet composition on female CHC profiles across ages, with dietary yeast and sugar driving CHC changes in opposite directions. Surprisingly, however, we found no evidence that these changes affect female attractiveness. Multivariate comparisons among responses of CHC profiles to diet, aging, and insulin signaling suggest that diet may alter the levels of some CHCs in a way that results in profiles that are more attractive while simultaneously altering other CHCs in a way that makes them less attractive. For example, changes in short-chain CHCs induced by a high-yeast diet phenocopy changes caused by aging and by decreased insulin signaling, both of which result in less attractive females. On the other hand, changes in long-chain CHCs in response to the same diet result in levels that are comparable to those observed in attractive young females and females with increased insulin signaling. The effects of a high-sugar diet tend in the opposite direction, as levels of short-chain CHCs resemble those in attractive females with increased insulin signaling and changes in long-chain CHCs are similar to those caused by decreased insulin signaling. Together, these data suggest that diet-dependent changes in female CHCs may be sending conflicting messages to males.
Variation in cuticular hydrocarbons among strains of the Anopheles gambiae sensu stricto by analysis of cuticular hydrocarbons using gas liquid chromatography of larvae
Anyanwu, Greg I;Molyneux, David H;Phillips, Angela;
Memórias do Instituto Oswaldo Cruz , 2000, DOI: 10.1590/S0074-02762000000300003
Abstract: cuticular hydrocarbons of larvae of individual strains of the anopheles gambiae sensu stricto were investigated using gas liquid chromatography. biomedical discriminant analysis involving multivariate statistics suggests that there was clear hydrocarbon difference between the gambian(g3), the nigerian (16css and, its malathion resistant substrain, refma) and the tanzanian (kwa) strains. the high degree of segregation (95%) in hydrocarbons among the four strains investigated indicates that further analysis is needed to enable understanding of hydrocarbon variation in samples of an. gambiae especially from areas where these populations co-exist.
Variation in cuticular hydrocarbons among strains of the Anopheles gambiae sensu stricto by analysis of cuticular hydrocarbons using gas liquid chromatography of larvae  [cached]
Anyanwu Greg I,Molyneux David H,Phillips Angela
Memórias do Instituto Oswaldo Cruz , 2000,
Abstract: Cuticular hydrocarbons of larvae of individual strains of the Anopheles gambiae sensu stricto were investigated using gas liquid chromatography. Biomedical discriminant analysis involving multivariate statistics suggests that there was clear hydrocarbon difference between the Gambian(G3), the Nigerian (16CSS and, its malathion resistant substrain, REFMA) and the Tanzanian (KWA) strains. The high degree of segregation (95%) in hydrocarbons among the four strains investigated indicates that further analysis is needed to enable understanding of hydrocarbon variation in samples of An. gambiae especially from areas where these populations co-exist.
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