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Leigh W Simmons - One of the best experts on this subject based on the ideXlab platform.
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no coolidge effect in the australian Field Cricket teleogryllus oceanicus orthoptera gryllidae
Australian Journal of Entomology, 2015Co-Authors: Melissa L Thomas, Leigh W SimmonsAbstract:A progressive decline in a male's propensity to mate with the same female, combined with a heightened sexual interest in new females, is known as the Coolidge effect. The Coolidge effect has been reported in a number of taxa and is thought to be adaptive, as males distribute sperm evenly across multiple females thereby maximising fitness. Here we looked for the Coolidge effect in the Australian Field Cricket, Teleogryllus oceanicus (Le Guillou). We found that males did not show greater sexual interest in novel females compared with their previous mates. Moreover, we did not find any decline in the quality of ejaculates transferred by males when mating sequentially with the same female, or an increase in ejaculate quality when males were presented with novel females. Our results are in contrast with findings investigating the Coolidge effect in other insects, which may reflect differences among species in the fitness benefits associated with mating repeatedly with the same female. We argue that examinations of the Coolidge effect need to be incorporated routinely into studies that examine the benefits of polyandry for females, because of the potential impact of reduced ejaculate expenditure by males in monandrous treatments.
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acoustic cues alter perceived sperm competition risk in the Field Cricket teleogryllus oceanicus
Behavioral Ecology, 2013Co-Authors: Brian Gray, Leigh W SimmonsAbstract:Sperm competition game theory predicts that males should respond to increasing sperm competition risk by increasing ejaculate expenditure. There is considerable support for this prediction from a diverse range of taxa. However, the cues males use to assess risk and the fitness returns for strategic ejaculation are less well understood. We explored the role of acoustic cues in the assessment of sperm competition risk by manipulating male experience of acoustically signaling conspecifics in the Field Cricket Teleogryllus oceanicus. Compared with males reared in acoustic isolation, males reared in song-dense environments mimicking a high sperm competition risk produced ejaculates with a greater percentage of viable sperm. However, acoustic experience had only a weak and nonsignificant effect on competitive fertilization success. We argue that female influences on paternity are likely to have a strong moderating effect on male fitness returns from prudent allocation and call for more studies that address the consequences of strategic ejaculation for male fitness.
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Tissue-Specific Transcriptomics in the Field Cricket Teleogryllus oceanicus
G3 (Bethesda Md.), 2013Co-Authors: Nathan W. Bailey, Paris Veltsos, Yew-foon Tan, A. Harvey Millar, Michael G. Ritchie, Leigh W SimmonsAbstract:Field Crickets (family Gryllidae) frequently are used in studies of behavioral genetics, sexual selection, and sexual conflict, but there have been no studies of transcriptomic differences among different tissue types. We evaluated transcriptome variation among testis, accessory gland, and the remaining whole-body preparations from males of the Field Cricket, Teleogryllus oceanicus. Non-normalized cDNA libraries from each tissue were sequenced on the Roche 454 platform, and a master assembly was constructed using testis, accessory gland, and whole-body preparations. A total of 940,200 reads were assembled into 41,962 contigs, to which 36,856 singletons (reads not assembled into a contig) were added to provide a total of 78,818 sequences used in annotation analysis. A total of 59,072 sequences (75%) were unique to one of the three tissues. Testis tissue had the greatest proportion of tissue-specific sequences (62.6%), followed by general body (56.43%) and accessory gland tissue (44.16%). We tested the hypothesis that tissues expressing gene products expected to evolve rapidly as a result of sexual selection—testis and accessory gland—would yield a smaller proportion of BLASTx matches to homologous genes in the model organism Drosophila melanogaster compared with whole-body tissue. Uniquely expressed sequences in both testis and accessory gland showed a significantly lower rate of matching to annotated D. melanogaster genes compared with those from general body tissue. These results correspond with empirical evidence that genes expressed in testis and accessory gland tissue are rapidly evolving targets of selection.
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cuticular hydrocarbons influence female attractiveness to males in the australian Field Cricket teleogryllus oceanicus
Journal of Evolutionary Biology, 2010Co-Authors: Melissa L Thomas, Leigh W SimmonsAbstract:Sexual dimorphism is thought to result from directional sexual selection acting on male signal traits, with female signal traits given little, if any, attention. Here, we examine male mating preferences in the Australian Field Cricket, Teleogryllus oceanicus. Using a multivariate selection analysis approach, we found that male preferences have the potential to exert selection on female cuticular hydrocarbons, chemical compounds widely used as sexual signals in insects. In addition to finding both stabilizing and disruptive preference gradients, we also found weak negative directional preference for female cuticular hydrocarbons. We contrast our results with a recent study examining sexual selection via female choice on male T. oceanicus cuticular hydrocarbons and suggest that differences in the form and intensity of sexual selection between the genders may provide part of the net selection differential necessary for the evolution of sexual dimorphism in this species.
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male dominance influences pheromone expression ejaculate quality and fertilization success in the australian Field Cricket teleogryllus oceanicus
Behavioral Ecology, 2009Co-Authors: Melissa L Thomas, Leigh W SimmonsAbstract:The outcome of fights between males can often represent an honest signal of male quality and are therefore widely used by females in mate choice. Indeed, female preference for males that win fights has been demonstrated in numerous animal taxa, and many recent studies have focused attention on how subordinate males compensate for this disadvantage through postcopulatory mating strategies, such as increased investment in their ejaculates. Here, using the Australian Field Cricket, Teleogryllus oceanicus, we show that rather than investing more in postcopulatory strategies, subordinate males invest in an alternative precopulatory mating approach. We find that subordinate males produce ejaculates of lower quality than dominate males and sire less offspring when competing for fertilizations. However, subordinate males upregulate the quantity of a number of cuticular compounds that have previously been shown to increase male mating success. Our results suggest that male reproductive success is likely to result from the interaction of multiple traits in this species. Copyright 2009, Oxford University Press.
John T. Rotenberry - One of the best experts on this subject based on the ideXlab platform.
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sexual signal loss the link between behaviour and rapid evolutionary dynamics in a Field Cricket
Journal of Animal Ecology, 2018Co-Authors: Marlene Zuk, John T. Rotenberry, Nathan W. Bailey, Brian GrayAbstract:Sexual signals may be acquired or lost over evolutionary time, and are tempered in their exaggeration by natural selection. In the Pacific Field Cricket, Teleogryllus oceanicus, a mutation ("flatwing") causing loss of the sexual signal, the song, spread in <20 generations in two of three Hawaiian islands where the Crickets have been introduced. Flatwing (as well as some normal-wing) males behave as satellites, moving towards and settling near calling males to intercept phonotactic females. From 2005 to 2012, we surveyed Crickets and their responses to conspecific song, noting the morph and number of males and females before and after experimental playbacks. The three Hawaiian islands consistently contained different proportions of flatwing Crickets, ranging from about 90% of males on Kauai to 50% on Oahu to rare on the Big Island of Hawaii. Flatwing and normal-wing males do not appear to differ in responsiveness to playback, a behaviour that should influence the likelihood of a male encountering a phonotactic female. Instead, male and female Crickets from populations in which little to no calling song is perceptible during development tended to seek out callers more readily than Crickets that developed in noisier environments. Such increased phonotaxis makes females more likely to find either the caller to which they are responding or to encounter a flatwing (or normal male satellite) that has also been attracted to the song. Our evidence suggests that pre-existing behavioural plasticity (manifest as flexible responses to social-particularly acoustic-information in the environment) is associated with the rapid spread of the flatwing trait. Different social environments select for differential success of flatwing or normal-wing males, which in turn alters the social environment itself.
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geographical variation in calling song of the Field Cricket teleogryllus oceanicus the importance of spatial scale
Journal of Evolutionary Biology, 2008Co-Authors: Marlene Zuk, John T. Rotenberry, Leigh W SimmonsAbstract:We compared calling songs of the Field Cricket Teleogryllus oceanicus from 15 sites within six regions of two continental areas, Oceania and Australia. The Cricket was introduced to Hawaii, where it is subject to an acoustically orienting parasitoid fly not found elsewhere in its range. In a principal components analysis (PCA) of song from all populations combined, the first five components had eigenvalues greater than one, and collectively accounted for over 80% of the total variation. Means for all song components varied significantly among sites, and different components varied at the three levels of analysis (continent, region and site). The principal way in which sites differed was along a gradient in increasing song length, pulse duration and intervals between song elements. Crickets from Oceania had a significantly greater variance in their song than Australian Crickets, driven largely by the high variance in Hawaii. Geography explained a substantial amount of variation in song, despite the likelihood of serial bottlenecks having occurred as the species moved from island to island. Because female Crickets appear not to focus on the short chirp as a component of mate choice, a lack of selection may allow this song component to vary more widely.
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Acoustically-orienting parasitoids in calling and silent males of the Field Cricket Teleogryllus oceanicus
Ecological Entomology, 1995Co-Authors: Marlene Zuk, Leigh W Simmons, John T. RotenberryAbstract:. 1 On three Hawaiian Islands, the introduced Australasian Field Cricket Teleogryllus oceanicus Le Guillou (Orthoptera: Gryllidae) was found to be attacked by the phonotactic parasitoid tachinid fly, Ormia ochracea Bigot. 2 Noncalling males occurred with callers in all locations, but silent males were more heavily parasitized than callers. 3 Body size was unrelated to both calling status and the likelihood of harbouring parasitoid larvae. 4 An experiment examining the likelihood of calling in the laboratory by males collected as silent or calling individuals showed no difference between the two classes of males, after accounting for parasitoid levels; males harbouring larvae were less likely to call.
Melissa L Thomas - One of the best experts on this subject based on the ideXlab platform.
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no coolidge effect in the australian Field Cricket teleogryllus oceanicus orthoptera gryllidae
Australian Journal of Entomology, 2015Co-Authors: Melissa L Thomas, Leigh W SimmonsAbstract:A progressive decline in a male's propensity to mate with the same female, combined with a heightened sexual interest in new females, is known as the Coolidge effect. The Coolidge effect has been reported in a number of taxa and is thought to be adaptive, as males distribute sperm evenly across multiple females thereby maximising fitness. Here we looked for the Coolidge effect in the Australian Field Cricket, Teleogryllus oceanicus (Le Guillou). We found that males did not show greater sexual interest in novel females compared with their previous mates. Moreover, we did not find any decline in the quality of ejaculates transferred by males when mating sequentially with the same female, or an increase in ejaculate quality when males were presented with novel females. Our results are in contrast with findings investigating the Coolidge effect in other insects, which may reflect differences among species in the fitness benefits associated with mating repeatedly with the same female. We argue that examinations of the Coolidge effect need to be incorporated routinely into studies that examine the benefits of polyandry for females, because of the potential impact of reduced ejaculate expenditure by males in monandrous treatments.
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cuticular hydrocarbons influence female attractiveness to males in the australian Field Cricket teleogryllus oceanicus
Journal of Evolutionary Biology, 2010Co-Authors: Melissa L Thomas, Leigh W SimmonsAbstract:Sexual dimorphism is thought to result from directional sexual selection acting on male signal traits, with female signal traits given little, if any, attention. Here, we examine male mating preferences in the Australian Field Cricket, Teleogryllus oceanicus. Using a multivariate selection analysis approach, we found that male preferences have the potential to exert selection on female cuticular hydrocarbons, chemical compounds widely used as sexual signals in insects. In addition to finding both stabilizing and disruptive preference gradients, we also found weak negative directional preference for female cuticular hydrocarbons. We contrast our results with a recent study examining sexual selection via female choice on male T. oceanicus cuticular hydrocarbons and suggest that differences in the form and intensity of sexual selection between the genders may provide part of the net selection differential necessary for the evolution of sexual dimorphism in this species.
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male dominance influences pheromone expression ejaculate quality and fertilization success in the australian Field Cricket teleogryllus oceanicus
Behavioral Ecology, 2009Co-Authors: Melissa L Thomas, Leigh W SimmonsAbstract:The outcome of fights between males can often represent an honest signal of male quality and are therefore widely used by females in mate choice. Indeed, female preference for males that win fights has been demonstrated in numerous animal taxa, and many recent studies have focused attention on how subordinate males compensate for this disadvantage through postcopulatory mating strategies, such as increased investment in their ejaculates. Here, using the Australian Field Cricket, Teleogryllus oceanicus, we show that rather than investing more in postcopulatory strategies, subordinate males invest in an alternative precopulatory mating approach. We find that subordinate males produce ejaculates of lower quality than dominate males and sire less offspring when competing for fertilizations. However, subordinate males upregulate the quantity of a number of cuticular compounds that have previously been shown to increase male mating success. Our results suggest that male reproductive success is likely to result from the interaction of multiple traits in this species. Copyright 2009, Oxford University Press.
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Sexual selection on cuticular hydrocarbons in the Australian Field Cricket, Teleogryllus oceanicus.
BMC evolutionary biology, 2009Co-Authors: Melissa L Thomas, Leigh W SimmonsAbstract:Background Females in a wide range of taxa have been shown to base their choice of mates on pheromone signals. However, little research has focussed specifically on the form and intensity of selection that mate choice imposes on the pheromone signal. Using multivariate selection analysis, we characterise directly the form and intensity of sexual selection acting on cuticular hydrocarbons, chemical compounds widely used in the selection of mates in insects. Using the Australian Field Cricket Teleogryllus oceanicus as a model organism, we use three measures of male attractiveness to estimate fitness; mating success, the duration of courtship required to elicit copulation, and subsequent spermatophore attachment duration.
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sexual dimorphism in cuticular hydrocarbons of the australian Field Cricket teleogryllus oceanicus orthoptera gryllidae
Journal of Insect Physiology, 2008Co-Authors: Melissa L Thomas, Leigh W SimmonsAbstract:Sexual dimorphism is presumed to reflect adaptive divergence in response to selection favouring different optimal character states in the two sexes. Here, we analyse patterns of sexual dimorphism in the cuticular hydrocarbons of the Australian Field Cricket Teleogryllus oceanicus using gas chromatography. Ten of the 25 peaks found in our chromatographs, differed in their relative abundance between the sexes. The presence of sexual dimorphism in T. oceanicus is discussed in reference to a review of sexual dimorphism in cuticular hydrocarbons of other insects. We found that this trait has been examined in 103 species across seven different orders. Seventy-six of these species (73%) displayed sex specificity of cuticular hydrocarbons, the presence/absence of which does not appear to be directly linked to phylogeny. The occurrence of sexual dimorphism in cuticular hydrocarbons of some but not other species, and the extent of variation within genera, suggest that this divergence has been driven primarily by sexual selection.
Nathan W. Bailey - One of the best experts on this subject based on the ideXlab platform.
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sexual signal loss the link between behaviour and rapid evolutionary dynamics in a Field Cricket
Journal of Animal Ecology, 2018Co-Authors: Marlene Zuk, John T. Rotenberry, Nathan W. Bailey, Brian GrayAbstract:Sexual signals may be acquired or lost over evolutionary time, and are tempered in their exaggeration by natural selection. In the Pacific Field Cricket, Teleogryllus oceanicus, a mutation ("flatwing") causing loss of the sexual signal, the song, spread in <20 generations in two of three Hawaiian islands where the Crickets have been introduced. Flatwing (as well as some normal-wing) males behave as satellites, moving towards and settling near calling males to intercept phonotactic females. From 2005 to 2012, we surveyed Crickets and their responses to conspecific song, noting the morph and number of males and females before and after experimental playbacks. The three Hawaiian islands consistently contained different proportions of flatwing Crickets, ranging from about 90% of males on Kauai to 50% on Oahu to rare on the Big Island of Hawaii. Flatwing and normal-wing males do not appear to differ in responsiveness to playback, a behaviour that should influence the likelihood of a male encountering a phonotactic female. Instead, male and female Crickets from populations in which little to no calling song is perceptible during development tended to seek out callers more readily than Crickets that developed in noisier environments. Such increased phonotaxis makes females more likely to find either the caller to which they are responding or to encounter a flatwing (or normal male satellite) that has also been attracted to the song. Our evidence suggests that pre-existing behavioural plasticity (manifest as flexible responses to social-particularly acoustic-information in the environment) is associated with the rapid spread of the flatwing trait. Different social environments select for differential success of flatwing or normal-wing males, which in turn alters the social environment itself.
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divergent mechanisms of acoustic mate recognition between closely related Field Cricket species teleogryllus spp
Animal Behaviour, 2017Co-Authors: Nathan W. Bailey, Peter Moran, Matthias R HennigAbstract:Effective recognition of conspecific mating signals reduces the risk of maladaptive hybridization. Dissecting the signal recognition algorithms that underlie preferences is a useful approach for testing whether closely related taxa evaluate the same or different signal features to achieve mate recognition. Such data provide information about potential constraints and targets of selection during evolutionary divergence. Using a series of mate choice trials, we tested whether closely related, but genetically and phenotypically divergent, Field Cricket species ( Teleogryllus oceanicus and Teleogryllus commodus ) use shared or distinct recognition algorithms when evaluating acoustic male calling songs. These species overlap in sympatry, show premating isolation based on female discrimination of male calling songs, yet are capable of producing hybrid offspring. Unexpectedly, female selectivity for features of male song differed between the two species. We found that the two species use a combination of shared and unique signal filtering mechanisms, and we characterized how information about male carrier frequency, pulse rate and temporal patterning is integrated to achieve song recognition in each species. These results illustrate how comparatively few, simple modifications in key components of signal recognition algorithms can lead to striking interspecific discrimination between closely related taxa, despite apparent signal complexity. The finding that some steps during signal recognition and filtering are shared between the species, while others differ, can help to identify behavioural traits targeted by selection during evolutionary divergence.
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Tissue-Specific Transcriptomics in the Field Cricket Teleogryllus oceanicus
G3 (Bethesda Md.), 2013Co-Authors: Nathan W. Bailey, Paris Veltsos, Yew-foon Tan, A. Harvey Millar, Michael G. Ritchie, Leigh W SimmonsAbstract:Field Crickets (family Gryllidae) frequently are used in studies of behavioral genetics, sexual selection, and sexual conflict, but there have been no studies of transcriptomic differences among different tissue types. We evaluated transcriptome variation among testis, accessory gland, and the remaining whole-body preparations from males of the Field Cricket, Teleogryllus oceanicus. Non-normalized cDNA libraries from each tissue were sequenced on the Roche 454 platform, and a master assembly was constructed using testis, accessory gland, and whole-body preparations. A total of 940,200 reads were assembled into 41,962 contigs, to which 36,856 singletons (reads not assembled into a contig) were added to provide a total of 78,818 sequences used in annotation analysis. A total of 59,072 sequences (75%) were unique to one of the three tissues. Testis tissue had the greatest proportion of tissue-specific sequences (62.6%), followed by general body (56.43%) and accessory gland tissue (44.16%). We tested the hypothesis that tissues expressing gene products expected to evolve rapidly as a result of sexual selection—testis and accessory gland—would yield a smaller proportion of BLASTx matches to homologous genes in the model organism Drosophila melanogaster compared with whole-body tissue. Uniquely expressed sequences in both testis and accessory gland showed a significantly lower rate of matching to annotated D. melanogaster genes compared with those from general body tissue. These results correspond with empirical evidence that genes expressed in testis and accessory gland tissue are rapidly evolving targets of selection.
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mate choice plasticity in the Field Cricket teleogryllus oceanicus effects of social experience in multiple modalities
Behavioral Ecology and Sociobiology, 2011Co-Authors: Nathan W. BaileyAbstract:Social experience can elicit phenotypically plastic changes in mate choice, but little is known about the degree to which social information from one modality can influence mating decisions based on information from a different modality. I used the Field Cricket Teleogryllus oceanicus to test whether experience of chemical cues mimicking a high density of sexually mature males causes changes in mate choice based on acoustic signals. T. oceanicus males produce long-range calling songs to attract females for mating, but they also produce waxy, non-volatile hydrocarbons on their cuticle (CHCs) which, when deposited on a substrate, can be detected by females and may provide demographic information. I manipulated female experience of substrate-bound male CHCs and then performed acoustic mate choice trials. When CHCs were present on the substrate during trials, females showed greater motivation to respond to male calling song. This effect diminished with repeated exposure to male songs, demonstrating that the importance of olfactory cues in altering acoustic mate choice decreased with increasing exposure to acoustic signals. However, the temporal nature of CHC experience mattered: previous experience of CHCs did not alter subsequent female choice for male calling song traits. Exposure to male song increased the threshold of mate acceptance over time, and individuals varied considerably in overall levels of responsiveness. Taken together, the results demonstrate that mate choice is dependent on social context mediated by multiple modalities in T. oceanicus, but they do not support the idea that prior experience of social cues in one modality necessarily influences later mating decisions based on other signalling modalities.
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Courtship song's role during female mate choice in the Field Cricket Teleogryllus oceanicus
Behavioral Ecology, 2009Co-Authors: Darren Rebar, Nathan W. Bailey, Marlene ZukAbstract:Sexual signals consist of multiple components, each of which can contribute to mating decisions. Male Field Crickets use 2 acoustic signals in the context of mating: a calling song that attracts females from a distance and a courtship song that follows once a female makes physical contact with a male. The function of courtship is unclear because females have already chosen and approached a particular male based on his calling song. Using the Field Cricket Teleogryllus oceanicus, we tested whether females evaluate the attractiveness of males based on their courtship song irrespective of other male qualities. In a tournament-style assay, females chose males based on elements of their courtship song and preferred males with longer courtship songs that had a higher duty cycle (more sound per unit time). Courtship song was also highly repeatable not only within a bout but also between days in the presence of different females. Additionally, we manipulated the attractiveness of males to females by surgically silencing males and broadcasting playbacks of artificially constructed courtship songs. When we broadcast a preferred song model during courtship by previously nonpreferred males, females showed greater attraction, and vice versa. Courtship song may be particularly important in systems with satellite males that do not produce long-range signals because it gives females their only opportunity to evaluate potential mates. Copyright 2009, Oxford University Press.
Brian Gray - One of the best experts on this subject based on the ideXlab platform.
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sexual signal loss the link between behaviour and rapid evolutionary dynamics in a Field Cricket
Journal of Animal Ecology, 2018Co-Authors: Marlene Zuk, John T. Rotenberry, Nathan W. Bailey, Brian GrayAbstract:Sexual signals may be acquired or lost over evolutionary time, and are tempered in their exaggeration by natural selection. In the Pacific Field Cricket, Teleogryllus oceanicus, a mutation ("flatwing") causing loss of the sexual signal, the song, spread in <20 generations in two of three Hawaiian islands where the Crickets have been introduced. Flatwing (as well as some normal-wing) males behave as satellites, moving towards and settling near calling males to intercept phonotactic females. From 2005 to 2012, we surveyed Crickets and their responses to conspecific song, noting the morph and number of males and females before and after experimental playbacks. The three Hawaiian islands consistently contained different proportions of flatwing Crickets, ranging from about 90% of males on Kauai to 50% on Oahu to rare on the Big Island of Hawaii. Flatwing and normal-wing males do not appear to differ in responsiveness to playback, a behaviour that should influence the likelihood of a male encountering a phonotactic female. Instead, male and female Crickets from populations in which little to no calling song is perceptible during development tended to seek out callers more readily than Crickets that developed in noisier environments. Such increased phonotaxis makes females more likely to find either the caller to which they are responding or to encounter a flatwing (or normal male satellite) that has also been attracted to the song. Our evidence suggests that pre-existing behavioural plasticity (manifest as flexible responses to social-particularly acoustic-information in the environment) is associated with the rapid spread of the flatwing trait. Different social environments select for differential success of flatwing or normal-wing males, which in turn alters the social environment itself.
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acoustic cues alter perceived sperm competition risk in the Field Cricket teleogryllus oceanicus
Behavioral Ecology, 2013Co-Authors: Brian Gray, Leigh W SimmonsAbstract:Sperm competition game theory predicts that males should respond to increasing sperm competition risk by increasing ejaculate expenditure. There is considerable support for this prediction from a diverse range of taxa. However, the cues males use to assess risk and the fitness returns for strategic ejaculation are less well understood. We explored the role of acoustic cues in the assessment of sperm competition risk by manipulating male experience of acoustically signaling conspecifics in the Field Cricket Teleogryllus oceanicus. Compared with males reared in acoustic isolation, males reared in song-dense environments mimicking a high sperm competition risk produced ejaculates with a greater percentage of viable sperm. However, acoustic experience had only a weak and nonsignificant effect on competitive fertilization success. We argue that female influences on paternity are likely to have a strong moderating effect on male fitness returns from prudent allocation and call for more studies that address the consequences of strategic ejaculation for male fitness.