1
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Mitchell C, Wylde Z, Del Castillo E, Rapkin J, House CM, Hunt J. Beauty or function? The opposing effects of natural and sexual selection on cuticular hydrocarbons in male black field crickets. J Evol Biol 2023; 36:1266-1281. [PMID: 37534753 DOI: 10.1111/jeb.14198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 04/21/2023] [Accepted: 05/10/2023] [Indexed: 08/04/2023]
Abstract
Although many theoretical models of male sexual trait evolution assume that sexual selection is countered by natural selection, direct empirical tests of this assumption are relatively uncommon. Cuticular hydrocarbons (CHCs) are known to play an important role not only in restricting evaporative water loss but also in sexual signalling in most terrestrial arthropods. Insects adjusting their CHC layer for optimal desiccation resistance is often thought to come at the expense of successful sexual attraction, suggesting that natural and sexual selection are in opposition for this trait. In this study, we sampled the CHCs of male black field crickets (Teleogryllus commodus) using solid-phase microextraction and then either measured their evaporative water loss or mating success. We then used multivariate selection analysis to quantify the strength and form of natural and sexual selection targeting male CHCs. Both natural and sexual selection imposed significant linear and stabilizing selection on male CHCs, although for very different combinations. Natural selection largely favoured an increase in the total abundance of CHCs, especially those with a longer chain length. In contrast, mating success peaked at a lower total abundance of CHCs and declined as CHC abundance increased. However, mating success did improve with an increase in a number of specific CHC components that also increased evaporative water loss. Importantly, this resulted in the combination of male CHCs favoured by natural selection and sexual selection being strongly opposing. Our findings suggest that the balance between natural and sexual selection is likely to play an important role in the evolution of male CHCs in T. commodus and may help explain why CHCs are so divergent across populations and species.
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Affiliation(s)
- Christopher Mitchell
- Centre for Ecology & Conservation, School of Biosciences, University of Exeter, Cornwall Campus, Penryn, UK
| | - Zachariah Wylde
- School of Science, Western Sydney University, Hawkesbury Campus, Penrith, New South Wales, Australia
| | - Enrique Del Castillo
- Department of Industrial & Manufacturing Engineering and Department of Statistics, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - James Rapkin
- Centre for Ecology & Conservation, School of Biosciences, University of Exeter, Cornwall Campus, Penryn, UK
| | - Clarissa M House
- School of Science, Western Sydney University, Hawkesbury Campus, Penrith, New South Wales, Australia
| | - John Hunt
- Centre for Ecology & Conservation, School of Biosciences, University of Exeter, Cornwall Campus, Penryn, UK
- School of Science, Western Sydney University, Hawkesbury Campus, Penrith, New South Wales, Australia
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2
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Simmons LW, Lovegrove M, Du X(B, Ren Y, Thomas ML. Humidity stress and its consequences for male pre- and post-copulatory fitness traits in an insect. Ecol Evol 2023; 13:e10244. [PMID: 37404700 PMCID: PMC10316369 DOI: 10.1002/ece3.10244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 06/13/2023] [Accepted: 06/15/2023] [Indexed: 07/06/2023] Open
Abstract
Global declines in insect abundance are of significant concern. While there is evidence that climate change is contributing to insect declines, we know little of the direct mechanisms responsible for these declines. Male fertility is compromised by increasing temperatures, and the thermal limit to fertility has been implicated as an important factor in the response of insects to climate change. However, climate change is affecting both temperature and hydric conditions, and the effects of water availability on male fertility have rarely been considered. Here we exposed male crickets Teleogryllus oceanicus to either low or high-humidity environments while holding temperature constant. We measured water loss and the expression of both pre- and postmating reproductive traits. Males exposed to a low-humidity environment lost more water than males exposed to a high-humidity environment. A male's cuticular hydrocarbon profile (CHC) did not affect the amount of water lost, and males did not adjust the composition of their CHC profiles in response to hydric conditions. Males exposed to a low-humidity environment were less likely to produce courtship song or produced songs of low quality. Their spermatophores failed to evacuate and their ejaculates contained sperm of reduced viability. The detrimental effects of low-humidity on male reproductive traits will compromise male fertility and population persistence. We argue that limits to insect fertility based on temperature alone are likely to underestimate the true effects of climate change on insect persistence and that the explicit incorporation of water regulation into our modeling will yield more accurate predictions of the effects of climate change on insect declines.
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Affiliation(s)
- Leigh W. Simmons
- Centre for Evolutionary Biology, School of Biological SciencesThe University of Western AustraliaPerthWestern AustraliaAustralia
| | - Maxine Lovegrove
- Centre for Evolutionary Biology, School of Biological SciencesThe University of Western AustraliaPerthWestern AustraliaAustralia
| | - Xin (Bob) Du
- Harry Butler InstituteMurdoch UniversityPerthWestern AustraliaAustralia
| | - Yonglin Ren
- Harry Butler InstituteMurdoch UniversityPerthWestern AustraliaAustralia
| | - Melissa L. Thomas
- Harry Butler InstituteMurdoch UniversityPerthWestern AustraliaAustralia
- CSIRO Health and BiosecurityCSIRO Land and WaterFloreatWestern AustraliaAustralia
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3
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Moschilla JA, Tomkins JL, Simmons LW. Among-individual variation in behaviour and its effect on reproductive success. Anim Behav 2023. [DOI: 10.1016/j.anbehav.2023.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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4
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Simmons LW, Lovegrove M, Du B, Ren Y, Thomas ML. Ontogeny can provide insight into the roles of natural and sexual selection in cricket cuticular hydrocarbon evolution. J Exp Biol 2022; 225:276022. [PMID: 35848820 DOI: 10.1242/jeb.244375] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 07/12/2022] [Indexed: 11/20/2022]
Abstract
The often complex cocktails of hydrocarbon compounds found on the cuticles of insects can serve both naturally and sexually selected functions, contributing to an individual's ability to withstand water loss and attract mating partners. However, whether natural and sexual selection act synergistically or antagonistically on a species' cuticular hydrocarbon (CHC) profile remains unclear. Here we examined the ontogeny of the CHC profile in a species of cricket Teleogryllus oceanicus while manipulating humidity during development. We predicted that juvenile crickets should produce only those compounds that contribute to desiccation resistance, while those compounds contributing specifically to male attractiveness should be produced only at sexual maturity. Further, if attractive CHCs come at a cost to desiccation resistance as predicted by some models of sexual selection, then males reared under low humidity should be constrained to invest less in attractive CHCs. Crickets reared under low humidity produced more long chained methyl branched alkanes, alkenes and alkadienes than did crickets reared under high humidity. The abundance of n-alkanes was unaffected by humidity treatment. Sexual dimorphism in the CHC profile was not apparent until adult emergence and became exaggerated 10 days after emergence when crickets were sexually mature. Males produced more of the same compounds that were increased in both sexes under low humidity, but the humidity treatment did not interact with sex in determining CHC abundance. The data suggest that CHC profiles which protect crickets from desiccation might have synergistic effects on male attractiveness, as there was no evidence to suggest males trade-off a CHC profile produced in response to low humidity for one associated with sexual signalling.
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Affiliation(s)
- Leigh W Simmons
- Centre for Evolutionary Biology, School of Biological Sciences, The University of Western Australia, Crawley 6009, Australia
| | - Maxine Lovegrove
- Centre for Evolutionary Biology, School of Biological Sciences, The University of Western Australia, Crawley 6009, Australia
| | - Bob Du
- Harry Butler Institute, Murdoch University, Perth 6150, Australia
| | - Yonglin Ren
- Harry Butler Institute, Murdoch University, Perth 6150, Australia
| | - Melissa L Thomas
- Harry Butler Institute, Murdoch University, Perth 6150, Australia.,CSIRO Health and Biosecurity, CSIRO Land and Water, Floreat 6014, Australia
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5
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OUP accepted manuscript. Behav Ecol 2022. [DOI: 10.1093/beheco/arac049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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6
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Tanner JC, Simmons LW. Spoiled for choice: number of signalers constrains mate choice based on acoustic signals. Behav Ecol 2021. [DOI: 10.1093/beheco/arab136] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Animal communication mediates social interactions with important fitness consequences for individuals. Receivers use signals to detect and discriminate among potential mates. Extensive research effort has focused on how receiver behavior imposes selection on signalers and signals. However, animals communicate in socially and physically complex environments with important biotic and abiotic features that are often excluded from controlled laboratory experiments, including noise. “Noise” is any factor that prevents signal detection and discrimination. The noise caused by aggregates of acoustic signalers is a well-known impediment to receivers, but how many individual signalers are required to produce the emergent effects of chorus noise on receiver behavior? In Teleogryllus oceanicus, the Australian field cricket, we assayed female preferences for a temporal property of male advertisement signals, the number of long chirp pulses, using two-, four-, six-, and eight-choice phonotaxis experiments. We found that, as the number of individual signalers increased, receivers became less likely to respond phonotactically and less likely to express their well-documented preference for more long chirp pulses. We found that very few individual signalers can create a sufficiently noisy environment, due either to acoustic interference or choice overload, to substantially impair female preference expression. Our results suggest that receivers may not always be able to express their well-documented mating preferences in nature.
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Affiliation(s)
- Jessie C Tanner
- Centre for Evolutionary Biology, University of Western Australia, Crawley, WA 6009, Australia
| | - Leigh W Simmons
- Centre for Evolutionary Biology, University of Western Australia, Crawley, WA 6009, Australia
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7
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Zweerus NL, van Wijk M, Schal C, Groot AT. Experimental evidence for female mate choice in a noctuid moth. Anim Behav 2021. [DOI: 10.1016/j.anbehav.2021.06.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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8
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Vilella‐Pacheco Z, Mitchem LD, Formica VA, Brodie ED. Male competition reverses female preference for male chemical cues. Ecol Evol 2021; 11:4532-4541. [PMID: 33976828 PMCID: PMC8093714 DOI: 10.1002/ece3.7348] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 01/28/2021] [Accepted: 02/10/2021] [Indexed: 11/10/2022] Open
Abstract
Females must choose among potential mates with different phenotypes in a variety of social contexts. Many male traits are inherent and unchanging, but others are labile to social context. Competition, for example, can cause physiological changes that reflect recent wins and losses that fluctuate throughout time. We may expect females to respond differently to males depending on the outcome of their most recent fight. In Bolitotherus cornutus (forked fungus beetles), males compete for access to females, but copulation requires female cooperation. In this study, we use behavioral trials to determine whether females use chemical cues to differentiate between males and whether the outcome of recent male competition alters female preference. We measured female association time with chemical cues of two size-matched males both before and after male-male competition. Females in our study preferred to associate with future losers before males interacted, but changed their preference for realized winners following male competitive interactions. Our study provides the first evidence of change in female preference based solely on the outcome of male-male competition.
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Affiliation(s)
| | - Lisa D. Mitchem
- Mountain Lake Biological Station and Department of BiologyUniversity of VirginiaCharlottesvilleVAUSA
| | | | - Edmund D. Brodie
- Mountain Lake Biological Station and Department of BiologyUniversity of VirginiaCharlottesvilleVAUSA
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9
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Talavera JB, Collosi E, Clark MI, Robertson JM, Gray DA. Minimal prezygotic isolation between ecologically divergent sibling species. Biol J Linn Soc Lond 2021; 132:32-43. [PMID: 33390615 PMCID: PMC7761596 DOI: 10.1093/biolinnean/blaa178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 09/28/2020] [Indexed: 11/14/2022]
Abstract
Divergence in mating signals typically accompanies speciation. We examine two ecologically divergent sibling species of crickets to assess the degree and timing of the evolution of prezygotic reproductive isolation. Gryllus saxatilis occurs in rocky habitats throughout western North America with long-winged individuals capable of long-distance dispersal; Gryllus navajo is endemic to red-rock sandstone areas of south-eastern Utah and north-eastern Arizona and has short-winged individuals only capable of limited dispersal. Previous genetic work suggested some degree of introgression and/or incomplete lineage sorting is likely. Here we: (1) use restriction site associated DNA sequencing (RAD-seq) genetic data to describe the degree of genetic divergence among species and populations; (2) examine the strength of prezygotic isolation by (i) quantifying differences among male mating songs, and (ii) testing whether females prefer G. saxatilis or G. navajo calling songs. Our results show that genetically distinct "pure" species populations and genetically intermediate populations exist. Male mating songs are statistically distinguishable, but the absolute differences are small. In playback experiments, females from pure populations had no preference based on song; however, females from a genetically intermediate population preferred G. navajo song. Together these results suggest that prezygotic isolation is minimal, and mediated by female behaviour in admixed populations.
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Affiliation(s)
- Janelle B Talavera
- Department of Biology, California State University, Northridge, Northridge, CA, USA
| | - Emma Collosi
- Department of Biology, California State University, Northridge, Northridge, CA, USA
| | - Meaghan I Clark
- Department of Biology, California State University, Northridge, Northridge, CA, USA
| | - Jeanne M Robertson
- Department of Biology, California State University, Northridge, Northridge, CA, USA
| | - David A Gray
- Department of Biology, California State University, Northridge, Northridge, CA, USA
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10
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Berson JD, Zuk M, Simmons LW. Natural and sexual selection on cuticular hydrocarbons: a quantitative genetic analysis. Proc Biol Sci 2020; 286:20190677. [PMID: 31064302 DOI: 10.1098/rspb.2019.0677] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
While the reproductive benefits of sexual displays have been widely studied, we have relatively limited evidence of the fitness costs associated with most display traits. Insect cuticular hydrocarbon (CHC) profiles are sexually selected traits that also protect against desiccation. These two functions are thought to oppose each other, with investment in particular compounds believed to increase attractiveness at the expense of compounds that protect against water loss. We investigated this potential trade-off in a quantitative genetic framework using the Australian field cricket, Teleogryllus oceanicus. Several compounds were significantly genetically correlated with either attractiveness or desiccation resistance. Of these compounds, one was negatively genetically correlated with attractiveness but positively genetically correlated with desiccation resistance. Furthermore, scoring each individual's overall CHC profile for its level of attractiveness and desiccation resistance indicated a negative genetic correlation between these multivariate phenotypes. Together, our results provide evidence for a genetic trade-off between sexually and naturally selected functions of the CHC profile. We suggest that the production of an attractive CHC profile may be costly for males, but highlight the need for further work to support this finding experimentally. Genetic covariation between the CHC profile and attractiveness suggests that females can gain attractive sons through female choice.
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Affiliation(s)
- Jacob D Berson
- 1 Centre for Evolutionary Biology, School of Biological Sciences, The University of Western Australia , Crawley, Western Australia 6009 , Australia
| | - Marlene Zuk
- 2 Department of Ecology, Evolution and Behavior, and Minnesota Center for Philosophy of Science, University of Minnesota , Twin Cities, St Paul, MN 55108 , USA
| | - Leigh W Simmons
- 1 Centre for Evolutionary Biology, School of Biological Sciences, The University of Western Australia , Crawley, Western Australia 6009 , Australia
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11
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Moran PA, Hunt J, Mitchell C, Ritchie MG, Bailey NW. Sexual selection and population divergence III: Interspecific and intraspecific variation in mating signals. J Evol Biol 2020; 33:990-1005. [PMID: 32281707 DOI: 10.1111/jeb.13631] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 03/25/2020] [Accepted: 03/30/2020] [Indexed: 11/28/2022]
Abstract
A major challenge for studying the role of sexual selection in divergence and speciation is understanding the relative influence of different sexually selected signals on those processes in both intra- and interspecific contexts. Different signals may be more or less susceptible to co-option for species identification depending on the balance of sexual and ecological selection acting upon them. To examine this, we tested three predictions to explain geographic variation in long- versus short-range sexual signals across a 3,500 + km transect of two related Australian field cricket species (Teleogryllus spp.): (a) selection for species recognition, (b) environmental adaptation and (c) stochastic divergence. We measured male calling song and male and female cuticular hydrocarbons (CHCs) in offspring derived from wild populations, reared under common garden conditions. Song clearly differentiated the species, and no hybrids were observed suggesting that hybridization is rare or absent. Spatial variation in song was not predicted by geography, genetics or climatic factors in either species. In contrast, CHC divergence was strongly associated with an environmental gradient supporting the idea that the climatic environment selects more directly upon these chemical signals. In light of recently advocated models of diversification via ecological selection on secondary sexual traits, the different environmental associations we found for song and CHCs suggest that the impact of ecological selection on population divergence, and how that influences speciation, might be different for acoustic versus chemical signals.
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Affiliation(s)
- Peter A Moran
- Centre for Biological Diversity, School of Biology, University of St Andrews, Fife, UK
| | - John Hunt
- School of Science and Health, Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Christopher Mitchell
- School of Science and Health, Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - Michael G Ritchie
- Centre for Biological Diversity, School of Biology, University of St Andrews, Fife, UK
| | - Nathan W Bailey
- Centre for Biological Diversity, School of Biology, University of St Andrews, Fife, UK
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12
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Heinen‐Kay JL, Nichols RE, Zuk M. Sexual signal loss, pleiotropy, and maintenance of a male reproductive polymorphism in crickets. Evolution 2020; 74:1002-1009. [DOI: 10.1111/evo.13952] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 01/11/2020] [Accepted: 02/11/2020] [Indexed: 12/25/2022]
Affiliation(s)
- Justa L. Heinen‐Kay
- Department of Ecology, Evolution, and BehaviorUniversity of Minnesota St. Paul Minnesota 55108
| | - Rachel E. Nichols
- Department of Ecology, Evolution, and BehaviorUniversity of Minnesota St. Paul Minnesota 55108
| | - Marlene Zuk
- Department of Ecology, Evolution, and BehaviorUniversity of Minnesota St. Paul Minnesota 55108
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13
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Heggeseth B, Sim D, Partida L, Maroja LS. Influence of female cuticular hydrocarbon (CHC) profile on male courtship behavior in two hybridizing field crickets Gryllus firmus and Gryllus pennsylvanicus. BMC Evol Biol 2020; 20:21. [PMID: 32019492 PMCID: PMC7001378 DOI: 10.1186/s12862-020-1587-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 01/27/2020] [Indexed: 11/10/2022] Open
Abstract
Background The hybridizing field crickets, Gryllus firmus and Gryllus pennsylvanicus have several barriers that prevent gene flow between species. The behavioral pre-zygotic mating barrier, where males court conspecifics more intensely than heterospecifics, is important because by acting earlier in the life cycle it has the potential to prevent a larger fraction of hybridization. The mechanism behind such male mate preference is unknown. Here we investigate if the female cuticular hydrocarbon (CHC) profile could be the signal behind male courtship. Results While males of the two species display nearly identical CHC profiles, females have different, albeit overlapping profiles and some females (between 15 and 45%) of both species display a male-like profile distinct from profiles of typical females. We classified CHC females profile into three categories: G. firmus-like (F; including mainly G. firmus females), G. pennsylvanicus-like (P; including mainly G. pennsylvanicus females), and male-like (ML; including females of both species). Gryllus firmus males courted ML and F females more often and faster than they courted P females (p < 0.05). Gryllus pennsylvanicus males were slower to court than G. firmus males, but courted ML females more often (p < 0.05) than their own conspecific P females (no difference between P and F). Both males courted heterospecific ML females more often than other heterospecific females (p < 0.05, significant only for G. firmus males). Conclusions Our results suggest that male mate preference is at least partially informed by female CHC profile and that ML females elicit high courtship behavior in both species. Since ML females exist in both species and are preferred over other heterospecific females, it is likely that this female type is responsible for most hybrid offspring production.
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Affiliation(s)
- Brianna Heggeseth
- Department of Mathematics and Statistics, Williams College, Williamstown, MA, USA.,Department of Mathematics, Statistics, and Computer Science, Macalester College, St. Paul, MN, USA
| | - Danielle Sim
- Department of Biology, Williams College, Williamstown, MA, USA
| | - Laura Partida
- Department of Biology, Williams College, Williamstown, MA, USA
| | - Luana S Maroja
- Department of Biology, Williams College, Williamstown, MA, USA.
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14
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Pascoal S, Risse JE, Zhang X, Blaxter M, Cezard T, Challis RJ, Gharbi K, Hunt J, Kumar S, Langan E, Liu X, Rayner JG, Ritchie MG, Snoek BL, Trivedi U, Bailey NW. Field cricket genome reveals the footprint of recent, abrupt adaptation in the wild. Evol Lett 2019; 4:19-33. [PMID: 32055408 PMCID: PMC7006468 DOI: 10.1002/evl3.148] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 10/21/2019] [Accepted: 11/13/2019] [Indexed: 12/31/2022] Open
Abstract
Evolutionary adaptation is generally thought to occur through incremental mutational steps, but large mutational leaps can occur during its early stages. These are challenging to study in nature due to the difficulty of observing new genetic variants as they arise and spread, but characterizing their genomic dynamics is important for understanding factors favoring rapid adaptation. Here, we report genomic consequences of recent, adaptive song loss in a Hawaiian population of field crickets (Teleogryllus oceanicus). A discrete genetic variant, flatwing, appeared and spread approximately 15 years ago. Flatwing erases sound‐producing veins on male wings. These silent flatwing males are protected from a lethal, eavesdropping parasitoid fly. We sequenced, assembled and annotated the cricket genome, produced a linkage map, and identified a flatwing quantitative trait locus covering a large region of the X chromosome. Gene expression profiling showed that flatwing is associated with extensive genome‐wide effects on embryonic gene expression. We found that flatwing male crickets express feminized chemical pheromones. This male feminizing effect, on a different sexual signaling modality, is genetically associated with the flatwing genotype. Our findings suggest that the early stages of evolutionary adaptation to extreme pressures can be accompanied by greater genomic and phenotypic disruption than previously appreciated, and highlight how abrupt adaptation might involve suites of traits that arise through pleiotropy or genomic hitchhiking.
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Affiliation(s)
- Sonia Pascoal
- Department of Zoology University of Cambridge Cambridge CB2 3EJ United Kingdom
| | - Judith E Risse
- Division of Bioinformatics, Department of Plant Sciences Wageningen University & Research Wageningen 6708 PB The Netherlands.,Animal Ecology Netherlands Institute of Ecology Wageningen 6700 AB The Netherlands
| | - Xiao Zhang
- School of Biology University of St Andrews St Andrews Fife KY16 9TH United Kingdom
| | - Mark Blaxter
- Edinburgh Genomics University of Edinburgh Edinburgh EH9 3JT United Kingdom.,Institute of Evolutionary Biology University of Edinburgh Edinburgh EH9 3JT United Kingdom
| | - Timothee Cezard
- Edinburgh Genomics University of Edinburgh Edinburgh EH9 3JT United Kingdom
| | - Richard J Challis
- Edinburgh Genomics University of Edinburgh Edinburgh EH9 3JT United Kingdom
| | - Karim Gharbi
- Edinburgh Genomics University of Edinburgh Edinburgh EH9 3JT United Kingdom.,Earlham Institute Norwich Research Park Norwich NR4 7UZ United Kingdom
| | - John Hunt
- School of Science and Health and the Hawkesbury Institute for the Environment Western Sydney University Penrith NSW 2751 Australia.,Centre for Ecology and Conservation University of Exeter Penryn TR10 9FE United Kingdom
| | - Sujai Kumar
- Edinburgh Genomics University of Edinburgh Edinburgh EH9 3JT United Kingdom
| | - Emma Langan
- Edinburgh Genomics University of Edinburgh Edinburgh EH9 3JT United Kingdom.,School of Environmental Sciences University of East Anglia Norwich NR4 7UZ United Kingdom
| | - Xuan Liu
- Centre for Genomic Research University of Liverpool Liverpool L69 7ZB United Kingdom
| | - Jack G Rayner
- School of Biology University of St Andrews St Andrews Fife KY16 9TH United Kingdom
| | - Michael G Ritchie
- School of Biology University of St Andrews St Andrews Fife KY16 9TH United Kingdom
| | - Basten L Snoek
- Theoretical Biology and Bioinformatics Utrecht University Utrecht 3584 CH The Netherlands.,Terrestrial Ecology Netherlands Institute of Ecology Wageningen 6700 AB The Netherlands
| | - Urmi Trivedi
- Edinburgh Genomics University of Edinburgh Edinburgh EH9 3JT United Kingdom
| | - Nathan W Bailey
- School of Biology University of St Andrews St Andrews Fife KY16 9TH United Kingdom
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15
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Berdan E, Enge S, Nylund GM, Wellenreuther M, Martens GA, Pavia H. Genetic divergence and phenotypic plasticity contribute to variation in cuticular hydrocarbons in the seaweed fly Coelopa frigida. Ecol Evol 2019; 9:12156-12170. [PMID: 31832150 PMCID: PMC6854331 DOI: 10.1002/ece3.5690] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Revised: 08/19/2019] [Accepted: 08/26/2019] [Indexed: 12/24/2022] Open
Abstract
Cuticular hydrocarbons (CHCs) form the boundary between insects and their environments and often act as essential cues for species, mate, and kin recognition. This complex polygenic trait can be highly variable both among and within species, but the causes of this variation, especially the genetic basis, are largely unknown. In this study, we investigated phenotypic and genetic variation of CHCs in the seaweed fly, Coelopa frigida, and found that composition was affected by both genetic (sex and population) and environmental (larval diet) factors. We subsequently conducted behavioral trials that show CHCs are likely used as a sexual signal. We identified general shifts in CHC chemistry as well as individual compounds and found that the methylated compounds, mean chain length, proportion of alkenes, and normalized total CHCs differed between sexes and populations. We combined these data with whole genome resequencing data to examine the genetic underpinnings of these differences. We identified 11 genes related to CHC synthesis and found population-level outlier SNPs in 5 that are concordant with phenotypic differences. Together these results reveal that the CHC composition of C. frigida is dynamic, strongly affected by the larval environment, and likely under natural and sexual selection.
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Affiliation(s)
- Emma Berdan
- Department of Marine SciencesUniversity of GothenburgGöteborgSweden
| | - Swantje Enge
- Institute for Chemistry and Biology of the Marine EnvironmentCarl‐von‐Ossietzky University OldenburgWilhelmshavenGermany
- Department of Marine Sciences – TjärnöUniversity of GothenburgStrömstadSweden
| | - Göran M. Nylund
- Department of Marine Sciences – TjärnöUniversity of GothenburgStrömstadSweden
| | - Maren Wellenreuther
- Plant & Food Research LimitedNelsonNew Zealand
- School of Biological SciencesThe University of AucklandAucklandNew Zealand
| | | | - Henrik Pavia
- Department of Marine Sciences – TjärnöUniversity of GothenburgStrömstadSweden
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16
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Stamps GF, Shaw KL. Male use of chemical signals in sex discrimination of Hawaiian swordtail crickets (genus Laupala). Anim Behav 2019. [DOI: 10.1016/j.anbehav.2019.06.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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17
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Berson JD, Garcia-Gonzalez F, Simmons LW. Experimental evidence for the role of sexual selection in the evolution of cuticular hydrocarbons in the dung beetle, Onthophagus taurus. J Evol Biol 2019; 32:1186-1193. [PMID: 31420906 DOI: 10.1111/jeb.13519] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 07/08/2019] [Accepted: 08/12/2019] [Indexed: 11/28/2022]
Abstract
A role for sexual selection in the evolution of insect cuticular hydrocarbons (CHCs) is suggested by observations of selection acting on male CHCs during female mate choice. However, evidence that CHCs evolve in response to sexual selection is generally lacking, and there is a need to extend our understanding beyond well-studied taxa. Experimental evolution offers a powerful approach to investigate the effect of sexual selection on the evolution of insect CHCs. We conducted such an experiment using the dung beetle, Onthophagus taurus. After six, 12 and 21 generations of experimental evolution, we measured the CHCs of beetles from three populations subject to sexual selection and three populations within which sexual selection had been removed via enforced monogamy. We found that the male CHC profile responded to the experimental removal of sexual selection. Conversely, the CHC profile of females responded to the presence of sexual selection but not to its removal. These results show that sexual selection can be an important mechanism affecting the evolution of insect CHCs and that male and female CHCs can evolve independently.
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Affiliation(s)
- Jacob D Berson
- Centre for Evolutionary Biology, School of Biological Sciences, The University of Western Australia, Crawley, WA, Australia
| | - Francisco Garcia-Gonzalez
- Centre for Evolutionary Biology, School of Biological Sciences, The University of Western Australia, Crawley, WA, Australia.,Doñana Biological Station, Spanish Research Council CSIC, Sevilla, Spain
| | - Leigh W Simmons
- Centre for Evolutionary Biology, School of Biological Sciences, The University of Western Australia, Crawley, WA, Australia
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18
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Sakaluk SK, Oldzej J, Poppe CJ, Harper JL, Rines IG, Hampton KJ, Duffield KR, Hunt J, Sadd BM. Effects of inbreeding on life-history traits and sexual competency in decorated crickets. Anim Behav 2019. [DOI: 10.1016/j.anbehav.2019.05.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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19
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20
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Rebar D, Barbosa F, Greenfield MD. Female reproductive plasticity to the social environment and its impact on male reproductive success. Behav Ecol Sociobiol 2019. [DOI: 10.1007/s00265-019-2661-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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21
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Gilbert R, Uetz GW. Male chemical cues as reliable indicators of infection in the wolf spider
Schizocosa ocreata. Ethology 2019. [DOI: 10.1111/eth.12841] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Rachel Gilbert
- Department of Biological Sciences University of Cincinnati Cincinnati Ohio
| | - George W. Uetz
- Department of Biological Sciences University of Cincinnati Cincinnati Ohio
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22
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Moran PA, Hunt J, Mitchell C, Ritchie MG, Bailey NW. Behavioural mechanisms of sexual isolation involving multiple modalities and their inheritance. J Evol Biol 2018; 32:243-258. [DOI: 10.1111/jeb.13408] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 11/15/2018] [Accepted: 11/23/2018] [Indexed: 02/06/2023]
Affiliation(s)
- Peter A. Moran
- School of Biological, Earth and Environmental Sciences University College Cork Cork Ireland
| | - John Hunt
- School of Science and Health Hawkesbury Institute for the Environment Western Sydney University Penrith New South Wales Australia
- Centre for Ecology and Conservation University of Exeter Penryn UK
| | - Christopher Mitchell
- School of Science and Health Hawkesbury Institute for the Environment Western Sydney University Penrith New South Wales Australia
| | - Michael G. Ritchie
- Centre for Biological Diversity School of Biology University of St Andrews Fife UK
| | - Nathan W. Bailey
- Centre for Biological Diversity School of Biology University of St Andrews Fife UK
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23
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Dutta R, Balakrishnan R, Tregenza T. Divergence in Potential Contact Pheromones and Genital Morphology Among Sympatric Song Types of the Bush Cricket Mecopoda elongata. Front Ecol Evol 2018. [DOI: 10.3389/fevo.2018.00158] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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24
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Berson JD, Simmons LW. A costly chemical trait: phenotypic condition dependence of cuticular hydrocarbons in a dung beetle. J Evol Biol 2018; 31:1772-1781. [DOI: 10.1111/jeb.13371] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 08/08/2018] [Accepted: 08/28/2018] [Indexed: 12/13/2022]
Affiliation(s)
- Jacob D. Berson
- School of Biological Sciences Centre for Evolutionary Biology The University of Western Australia Crawley WA Australia
| | - Leigh W. Simmons
- School of Biological Sciences Centre for Evolutionary Biology The University of Western Australia Crawley WA Australia
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25
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Ng SH, Simpson SJ, Simmons LW. Macronutrients and micronutrients drive trade‐offs between male pre‐ and postmating sexual traits. Funct Ecol 2018. [DOI: 10.1111/1365-2435.13190] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Soon Hwee Ng
- Centre for Evolutionary Biology, School of Biological SciencesUniversity of Western Australia Crawley Western Australia Australia
| | - Stephen J. Simpson
- Charles Perkins Centre and School of Life and Environmental SciencesThe University of Sydney Sydney New South Wales Australia
| | - Leigh W. Simmons
- Centre for Evolutionary Biology, School of Biological SciencesUniversity of Western Australia Crawley Western Australia Australia
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26
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Berson JD, Simmons LW. Sexual selection across sensory modalities: female choice of male behavioral and gustatory displays. Behav Ecol 2018. [DOI: 10.1093/beheco/ary085] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Jacob D Berson
- Centre for Evolutionary Biology, School of Biological Sciences, The University of Western Australia, Crawley, Western Australia, Australia
| | - Leigh W Simmons
- Centre for Evolutionary Biology, School of Biological Sciences, The University of Western Australia, Crawley, Western Australia, Australia
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27
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The ‘hot male’ hypothesis: do female crickets prefer males with increased body temperature in mate choice scenarios? Anim Behav 2018. [DOI: 10.1016/j.anbehav.2018.02.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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28
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Beyer M, Czaczkes TJ, Tuni C. Does silk mediate chemical communication between the sexes in a nuptial feeding spider? Behav Ecol Sociobiol 2018. [DOI: 10.1007/s00265-018-2454-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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29
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Blankers T, Vilaça ST, Waurick I, Gray DA, Hennig RM, Mazzoni CJ, Mayer F, Berdan EL. Demography and selection shape transcriptomic divergence in field crickets. Evolution 2018; 72:553-567. [PMID: 29363111 DOI: 10.1111/evo.13435] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 12/18/2017] [Accepted: 01/05/2018] [Indexed: 12/12/2022]
Abstract
Gene flow, demography, and selection can result in similar patterns of genomic variation and disentangling their effects is key to understanding speciation. Here, we assess transcriptomic variation to unravel the evolutionary history of Gryllus rubens and Gryllus texensis, cryptic field cricket species with highly divergent mating behavior. We infer their demographic history and screen their transcriptomes for footprints of selection in the context of the inferred demography. We find strong support for a long history of bidirectional gene flow, which ceased during the late Pleistocene, and a bottleneck in G. rubens consistent with a peripatric origin of this species. Importantly, the demographic history has likely strongly shaped patterns of genetic differentiation (empirical FST distribution). Concordantly, FST -based selection detection uncovers a large number of outliers, likely comprising many false positives, echoing recent theoretical insights. Alternative genetic signatures of positive selection, informed by the demographic history of the sibling species, highlighted a smaller set of loci; many of these are candidates for controlling variation in mating behavior. Our results underscore the importance of demography in shaping overall patterns of genetic divergence and highlight that examining both demography and selection facilitates a more complete understanding of genetic divergence during speciation.
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Affiliation(s)
- Thomas Blankers
- Behavioural Physiology, Department of Biology, Humboldt-Universität zu Berlin, Berlin, Germany.,Museum für Naturkunde Berlin, Leibniz Institute for Evolution and Biodiversity Science, Berlin, Germany.,Department of Neurobiology and Behavior, Cornell University, Ithaca, New York 14853
| | - Sibelle T Vilaça
- Berlin Center for Genomics in Biodiversity Research (BeGenDiv), Berlin, Germany.,Leibniz-Institut für Zoo- und Wildtierforschung (IZW), Berlin, Germany
| | - Isabelle Waurick
- Museum für Naturkunde Berlin, Leibniz Institute for Evolution and Biodiversity Science, Berlin, Germany
| | - David A Gray
- Department of Biology, California State University Northridge, Northridge, California 91330
| | - R Matthias Hennig
- Behavioural Physiology, Department of Biology, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Camila J Mazzoni
- Berlin Center for Genomics in Biodiversity Research (BeGenDiv), Berlin, Germany.,Leibniz-Institut für Zoo- und Wildtierforschung (IZW), Berlin, Germany
| | - Frieder Mayer
- Museum für Naturkunde Berlin, Leibniz Institute for Evolution and Biodiversity Science, Berlin, Germany.,Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), Berlin, Germany
| | - Emma L Berdan
- Museum für Naturkunde Berlin, Leibniz Institute for Evolution and Biodiversity Science, Berlin, Germany.,Department of Marine Sciences, University of Gothenburg, Gothenburg SE-405 30, Sweden
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30
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Bertram SM, Loranger MJ, Thomson IR, Harrison SJ, Ferguson GL, Reifer ML, Corlett DH, Gowaty PA. Choosy males in Jamaican field crickets. Anim Behav 2017. [DOI: 10.1016/j.anbehav.2017.09.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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31
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Wegehaupt AK, Wagner WE. Females can solve the problem of low signal reliability by assessing multiple male traits. Biol Lett 2017; 13:rsbl.2017.0386. [PMID: 28904180 DOI: 10.1098/rsbl.2017.0386] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 08/23/2017] [Indexed: 11/12/2022] Open
Abstract
Male signals that provide information to females about mating benefits are often of low reliability. It is thus not clear why females often express strong signal preferences. We tested the hypothesis that females can distinguish between males with preferred signals that provide lower and higher quality direct benefits. In the field cricket, Gryllus lineaticeps, females usually prefer higher male chirp rates, but chirp rate is positively correlated with the fecundity benefits females will receive from males only for males that have experienced low quality diets. We paired females with muted males that were maintained on low or high nutrition diets, during the interactions we broadcast a replacement high chirp rate, and we observed whether females mated with the assigned male. Females were more likely to mate when paired with low nutrition males. These results suggest that females have evolved assessment mechanisms that allow them distinguish between males with preferred signals that provide high quality benefits (low nutrition males with high chirp rates) and males with preferred signals that provide low quality benefits (high nutrition males with high chirp rates).
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Affiliation(s)
- Abigail K Wegehaupt
- School of Biological Sciences, University of Nebraska, Lincoln, NE 68588-0118, USA
| | - William E Wagner
- School of Biological Sciences, University of Nebraska, Lincoln, NE 68588-0118, USA
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32
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Wehi PM, Monks A, Morgan-Richards M. Male tree weta are attracted to cuticular scent cues but do not discriminate according to sex or among two closely related species. Ethology 2017. [DOI: 10.1111/eth.12652] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Priscilla M. Wehi
- Institute of Agriculture & Environment; Massey University; Palmerston North New Zealand
- Landcare Research; Dunedin New Zealand
| | | | - Mary Morgan-Richards
- Institute of Agriculture & Environment; Massey University; Palmerston North New Zealand
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33
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Botha LM, Jones TM, Hopkins GR. Effects of lifetime exposure to artificial light at night on cricket (Teleogryllus commodus) courtship and mating behaviour. Anim Behav 2017. [DOI: 10.1016/j.anbehav.2017.05.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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34
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Pascoal S, Mendrok M, Wilson AJ, Hunt J, Bailey NW. Sexual selection and population divergence II. Divergence in different sexual traits and signal modalities in field crickets (Teleogryllus oceanicus
). Evolution 2017; 71:1614-1626. [DOI: 10.1111/evo.13239] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 02/28/2017] [Accepted: 03/08/2017] [Indexed: 01/23/2023]
Affiliation(s)
- Sonia Pascoal
- Department of Zoology; University of Cambridge; Cambridge CB2 3EJ United Kingdom
| | - Magdalena Mendrok
- Institute of Environmental Sciences; Jagellonian University; Gronostajova 7 30-387 Kraków Poland
| | - Alastair J. Wilson
- Centre for Ecology and Conservation, School of Biosciences; University of Exeter; Cornwall Campus TR10 9EZ United Kingdom
| | - John Hunt
- Centre for Ecology and Conservation, School of Biosciences; University of Exeter; Cornwall Campus TR10 9EZ United Kingdom
- School of Science and Health and Hawkesbury Institute for the Environment, Western Sydney University; Penrith NSW 2751 Australia
| | - Nathan W. Bailey
- Centre for Biological Diversity; University of St Andrews; St. Andrews KY16 9TH United Kingdom
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35
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Rapkin J, Jensen K, House CM, Sakaluk SK, Sakaluk JK, Hunt J. The complex interplay between macronutrient intake, cuticular hydrocarbon expression and mating success in male decorated crickets. J Evol Biol 2017; 30:711-727. [PMID: 28029711 DOI: 10.1111/jeb.13036] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 11/30/2016] [Accepted: 12/22/2016] [Indexed: 01/15/2023]
Abstract
The condition dependence of male sexual traits plays a central role in sexual selection theory. Relatively little, however, is known about the condition dependence of chemical signals used in mate choice and their subsequent effects on male mating success. Furthermore, few studies have isolated the specific nutrients responsible for condition-dependent variation in male sexual traits. Here, we used nutritional geometry to determine the effect of protein (P) and carbohydrate (C) intake on male cuticular hydrocarbon (CHC) expression and mating success in male decorated crickets (Gryllodes sigillatus). We show that both traits are maximized at a moderate-to-high intake of nutrients in a P:C ratio of 1 : 1.5. We also show that female precopulatory mate choice exerts a complex pattern of linear and quadratic sexual selection on this condition-dependent variation in male CHC expression. Structural equation modelling revealed that although the effect of nutrient intake on mating success is mediated through condition-dependent CHC expression, it is not exclusively so, suggesting that other traits must also play an important role. Collectively, our results suggest that the complex interplay between nutrient intake, CHC expression and mating success plays an important role in the operation of sexual selection in G. sigillatus.
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Affiliation(s)
- J Rapkin
- Centre for Ecology and Conservation, University of Exeter, Penryn, Cornwall, UK
| | - K Jensen
- Centre for Ecology and Conservation, University of Exeter, Penryn, Cornwall, UK.,Department of Bioscience, Terrestrial Ecology, Aarhus University, Silkeborg, Denmark
| | - C M House
- Centre for Ecology and Conservation, University of Exeter, Penryn, Cornwall, UK.,School of Science and Health, and Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
| | - S K Sakaluk
- Behaviour, Ecology, Evolution and Systematics Section, School of Biological Sciences, Illinois State University, Normal, IL, USA
| | - J K Sakaluk
- Department of Psychology, University of Victoria, Victoria, BC, Canada
| | - J Hunt
- Centre for Ecology and Conservation, University of Exeter, Penryn, Cornwall, UK.,School of Science and Health, and Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
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36
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Keagy J, Hosler LC, Borgia G. Female active sampling of male paint on bowers predicts female uncertainty in mate choice. Anim Behav 2016. [DOI: 10.1016/j.anbehav.2016.03.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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37
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Travers LM, Garcia-Gonzalez F, Simmons LW. Genetic variation but weak genetic covariation between pre- and post-copulatory episodes of sexual selection in Drosophila melanogaster. J Evol Biol 2016; 29:1535-52. [PMID: 27159063 DOI: 10.1111/jeb.12890] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 04/20/2016] [Accepted: 04/29/2016] [Indexed: 12/16/2022]
Abstract
When females mate polyandrously, male reproductive success depends both on the male's ability to attain matings and on his ability to outcompete rival males in the fertilization of ova post-copulation. Increased investment in ejaculate components may trade off with investment in precopulatory traits due to resource allocation. Alternatively, pre- and post-copulatory traits could be positively related if individuals can afford to invest heavily in traits advantageous at both episodes of selection. There is empirical evidence for both positive and negative associations between pre- and post-copulatory episodes, but little is known about the genetic basis of these correlations. In this study, we measured morphological, chemical and behavioural precopulatory male traits and investigated their relationship with measures of male fitness (male mating success, remating inhibition and offensive sperm competitiveness) across 40 isofemale lines of Drosophila melanogaster. We found significant variation among isofemale lines, indicating a genetic basis for most of the traits investigated. However, we found weak evidence for genetic correlations between precopulatory traits and our indices of male fitness. Moreover, pre- and post-copulatory episodes of selection were uncorrelated, suggesting selection may act independently at the different episodes to maximize male reproductive success.
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Affiliation(s)
- L M Travers
- Centre for Evolutionary Biology, School of Animal Biology (M092), The University of Western Australia, Crawley, WA, Australia
| | - F Garcia-Gonzalez
- Centre for Evolutionary Biology, School of Animal Biology (M092), The University of Western Australia, Crawley, WA, Australia.,Doñana Biological Station, Spanish Research Council CSIC, Isla de la Cartuja, Seville, Spain
| | - L W Simmons
- Centre for Evolutionary Biology, School of Animal Biology (M092), The University of Western Australia, Crawley, WA, Australia
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38
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Lane SM, Dickinson AW, Tregenza T, House CM. Sexual Selection on male cuticular hydrocarbons via male-male competition and female choice. J Evol Biol 2016; 29:1346-55. [PMID: 27037514 PMCID: PMC4999037 DOI: 10.1111/jeb.12875] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 03/31/2016] [Indexed: 01/25/2023]
Abstract
Traditional views of sexual selection assumed that male–male competition and female mate choice work in harmony, selecting upon the same traits in the same direction. However, we now know that this is not always the case and that these two mechanisms often impose conflicting selection on male sexual traits. Cuticular hydrocarbons (CHCs) have been shown to be linked to both social dominance and male attractiveness in several insect species. However, although several studies have estimated the strength and form of sexual selection imposed on male CHCs by female mate choice, none have established whether these chemical traits are also subject to sexual selection via male–male competition. Using a multivariate selection analysis, we estimate and compare sexual selection exerted by male–male competition and female mate choice on male CHC composition in the broad‐horned flour beetle Gnatocerus cornutus. We show that male–male competition exerts strong linear selection on both overall CHC abundance and body size in males, while female mate choice exerts a mixture of linear and nonlinear selection, targeting not just the overall amount of CHCs expressed but the relative abundance of specific hydrocarbons as well. We discuss the potential implications of this antagonistic selection with regard to male reproductive success.
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Affiliation(s)
- S M Lane
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Cornwall, UK
| | - A W Dickinson
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Cornwall, UK
| | - T Tregenza
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Cornwall, UK
| | - C M House
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Cornwall, UK
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39
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Pascoal S, Mendrok M, Mitchell C, Wilson AJ, Hunt J, Bailey NW. Sexual selection and population divergence I: The influence of socially flexible cuticular hydrocarbon expression in male field crickets (Teleogryllus oceanicus). Evolution 2016; 70:82-97. [PMID: 26678168 DOI: 10.1111/evo.12839] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 11/20/2015] [Accepted: 11/21/2015] [Indexed: 11/29/2022]
Abstract
Debates about how coevolution of sexual traits and preferences might promote evolutionary diversification have permeated speciation research for over a century. Recent work demonstrates that the expression of such traits can be sensitive to variation in the social environment. Here, we examined social flexibility in a sexually selected male trait-cuticular hydrocarbon (CHC) profiles-in the field cricket Teleogryllus oceanicus and tested whether population genetic divergence predicts the extent or direction of social flexibility in allopatric populations. We manipulated male crickets' social environments during rearing and then characterized CHC profiles. CHC signatures varied considerably across populations and also in response to the social environment, but our prediction that increased social flexibility would be selected in more recently founded populations exposed to fluctuating demographic environments was unsupported. Furthermore, models examining the influence of drift and selection failed to support a role of sexual selection in driving population divergence in CHC profiles. Variation in social environments might alter the dynamics of sexual selection, but our results align with theoretical predictions that the role social flexibility plays in modulating evolutionary divergence depends critically on whether responses to variation in the social environment are homogeneous across populations, or whether gene by social environment interactions occur.
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Affiliation(s)
- Sonia Pascoal
- Centre for Biological Diversity, University of St Andrews, St Andrews, Fife KY16 9TH, United Kingdom
| | - Magdalena Mendrok
- Institute of Environmental Sciences, Jagellonian University, Gronostajova 7, Kraków, 30-387, Poland
| | - Christopher Mitchell
- Hawkesbury Institute for the Environment, University of Western Sydney, Penrith, NSW, 2751, Australia.,Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Cornwall Campus, Cornwall, TR10 9EZ, United Kingdom
| | - Alastair J Wilson
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Cornwall Campus, Cornwall, TR10 9EZ, United Kingdom
| | - John Hunt
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Cornwall Campus, Cornwall, TR10 9EZ, United Kingdom
| | - Nathan W Bailey
- Centre for Biological Diversity, University of St Andrews, St Andrews, Fife KY16 9TH, United Kingdom.
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40
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Rebar D, Barbosa F, Greenfield MD. Acoustic experience influences male and female pre- and postcopulatory behaviors in a bushcricket. Behav Ecol 2015. [DOI: 10.1093/beheco/arv171] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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41
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Guillermo-Ferreira R, Bispo PC, Appel E, Kovalev A, Gorb SN. Mechanism of the wing colouration in the dragonfly Zenithoptera lanei (Odonata: Libellulidae) and its role in intraspecific communication. JOURNAL OF INSECT PHYSIOLOGY 2015; 81:129-36. [PMID: 26188874 DOI: 10.1016/j.jinsphys.2015.07.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Revised: 07/14/2015] [Accepted: 07/15/2015] [Indexed: 05/13/2023]
Abstract
Zenithoptera dragonflies are known for their remarkable bluish colouration on their wings and unique male behaviour of folding and unfolding their wings while perching. However, nothing is known about the optical properties of such colouration and its structural and functional background. In this paper, we aimed to study the relationship between the wing membrane ultrastructure, surface microstructure and colour spectra of male wings in Zenithoptera lanei and test the hypothesis that colouration functions as a signal in territorial fights between males. The results show that the specific wing colouration derives from interference in alternating layers of melanized and unmelanized cuticle in the wing membrane, combined with diffuse scattering in two different layers of wax crystals on the dorsal wing surface, one lower layer of long filaments, and one upper layer of leaf-shaped crystals. The results also show that the thicker wax coverage of the dorsal surface of the wings results in increased brightness and reduced chroma. In the field experiments, we have demonstrated that there is a reduction of aggressive reactions of rivals towards individuals with experimentally reduced amount of blue wing colouration.
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Affiliation(s)
- Rhainer Guillermo-Ferreira
- Department of Hydrobiology, Federal University of São Carlos, Rod. Washington Luis, km 235, São Carlos, São Paulo, Brazil; Department of Biological Sciences, São Paulo State University, Av. Dom Antônio 2100, Assis, São Paulo, Brazil; Department of Functional Morphology and Biomechanics, Zoological Institute, Kiel University, Am Botanischen Garten 1-9, D-24098 Kiel, Germany.
| | - Pitágoras C Bispo
- Department of Biological Sciences, São Paulo State University, Av. Dom Antônio 2100, Assis, São Paulo, Brazil
| | - Esther Appel
- Department of Functional Morphology and Biomechanics, Zoological Institute, Kiel University, Am Botanischen Garten 1-9, D-24098 Kiel, Germany
| | - Alexander Kovalev
- Department of Functional Morphology and Biomechanics, Zoological Institute, Kiel University, Am Botanischen Garten 1-9, D-24098 Kiel, Germany
| | - Stanislav N Gorb
- Department of Functional Morphology and Biomechanics, Zoological Institute, Kiel University, Am Botanischen Garten 1-9, D-24098 Kiel, Germany
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42
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Steiger S, Capodeanu-Nägler A, Gershman SN, Weddle CB, Rapkin J, Sakaluk SK, Hunt J. Female choice for male cuticular hydrocarbon profile in decorated crickets is not based on similarity to their own profile. J Evol Biol 2015; 28:2175-86. [PMID: 26301596 DOI: 10.1111/jeb.12740] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 08/14/2015] [Accepted: 08/18/2015] [Indexed: 11/30/2022]
Abstract
Indirect genetic benefits derived from female mate choice comprise additive (good genes) and nonadditive genetic benefits (genetic compatibility). Although good genes can be revealed by condition-dependent display traits, the mechanism by which compatibility alleles are detected is unclear because evaluation of the genetic similarity of a prospective mate requires the female to assess the genotype of the male and compare it to her own. Cuticular hydrocarbons (CHCs), lipids coating the exoskeleton of most insects, influence female mate choice in a number of species and offer a way for females to assess genetic similarity of prospective mates. Here, we determine whether female mate choice in decorated crickets is based on male CHCs and whether it is influenced by females' own CHC profiles. We used multivariate selection analysis to estimate the strength and form of selection acting on male CHCs through female mate choice, and employed different measures of multivariate dissimilarity to determine whether a female's preference for male CHCs is based on similarity to her own CHC profile. Female mating preferences were significantly influenced by CHC profiles of males. Male CHC attractiveness was not, however, contingent on the CHC profile of the choosing female, as certain male CHC phenotypes were equally attractive to most females, evidenced by significant linear and stabilizing selection gradients. These results suggest that additive genetic benefits, rather than nonadditive genetic benefits, accrue to female mate choice, in support of earlier work showing that CHC expression of males, but not females, is condition dependent.
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Affiliation(s)
- S Steiger
- Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Ulm, Germany
| | - A Capodeanu-Nägler
- Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Ulm, Germany
| | - S N Gershman
- Department of Evolution, Ecology and Organismal Biology, The Ohio State University at Marion, Marion, OH, USA
| | - C B Weddle
- Behavior, Ecology, Evolution and Systematics Section, School of Biological Sciences, Illinois State University, Normal, IL, USA
| | - J Rapkin
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn, UK
| | - S K Sakaluk
- Behavior, Ecology, Evolution and Systematics Section, School of Biological Sciences, Illinois State University, Normal, IL, USA
| | - J Hunt
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn, UK
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43
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Insect Cuticular Hydrocarbons as Dynamic Traits in Sexual Communication. INSECTS 2015; 6:732-42. [PMID: 26463413 PMCID: PMC4598662 DOI: 10.3390/insects6030732] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 07/10/2015] [Accepted: 07/29/2015] [Indexed: 11/17/2022]
Abstract
Recent research has demonstrated extensive within-species variation in pheromone expression in insect species, contrary to the view that pheromones are largely invariant within species. In fact, many studies on insect cuticular hydrocarbons (CHCs) show that pheromones can be highly dynamic traits that can express significant short-term plasticity across both abiotic and social environments. It is likely that this variability in CHC expression contributes to their important role in sexual signaling and mate choice. In this review, I discuss CHC plasticity and how this might influence sexual communication. I also highlight two important avenues for future research: examining plasticity in how individuals respond to CHC signals, and testing how sexual communication varies across abiotic and social environments.
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44
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Helanterä H, d'Ettorre P. A comparative study of egg recognition signature mixtures in Formica ants. Evolution 2015; 69:520-9. [PMID: 25545864 DOI: 10.1111/evo.12590] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2013] [Accepted: 12/04/2014] [Indexed: 11/28/2022]
Abstract
Processing of information from the environment, such as assessing group membership in social contexts, is a major determinant of inclusive fitness. For social insects, recognizing brood origin is crucial for inclusive fitness in many contexts, such as social parasitism and kin conflicts within colonies. Whether a recognition signature is informative in kin conflicts depends on the extent of a genetic contribution into the cues. We investigated colony- and matriline-specific variation in egg surface hydrocarbons in seven species of Formica ants. We show that chemical variance is distributed similarly to genetic variation, suggesting a significant genetic contribution to eggs odors in the genus. Significant among matriline components, and significant correlations between chemical and genetic similarity among individuals also indicate kin informative egg odors in several species. We suggest that egg odor surface variation could play a large role in within colony conflicts, and that a comparative method can reveal novel insight into communication of identity.
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Affiliation(s)
- Heikki Helanterä
- Centre of Excellence in Biological Interactions, Department of Bioscience, University of Helsinki, Helsinki, Finland; Tvärminne Zoological Station, University of Helsinki, Helsinki, Finland.
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45
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Ingleby FC, Hosken DJ, Flowers K, Hawkes MF, Lane SM, Rapkin J, House CM, Sharma MD, Hunt J. Environmental heterogeneity, multivariate sexual selection and genetic constraints on cuticular hydrocarbons in Drosophila simulans. J Evol Biol 2014; 27:700-13. [PMID: 24779049 DOI: 10.1111/jeb.12338] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Sexual selection is responsible for the evolution of many elaborate traits, but sexual trait evolution could be influenced by opposing natural selection as well as genetic constraints. As such, the evolution of sexual traits could depend heavily on the environment if trait expression and attractiveness vary between environments. Here, male Drosophila simulans were reared across a range of diets and temperatures, and we examined differences between these environments in terms of (i) the expression of male cuticular hydrocarbons (CHCs) and (ii) which male CHC profiles were most attractive to females. Temperature had a strong effect on male CHC expression, whereas the effect of diet was weaker. Male CHCs were subject to complex patterns of directional, quadratic and correlational sexual selection, and we found differences between environments in the combination of male CHCs that were most attractive to females, with clearer differences between diets than between temperatures. We also show that genetic covariance between environments is likely to cause a constraint on independent CHC evolution between environments. Our results demonstrate that even across the narrow range of environmental variation studied here, predicting the outcome of sexual selection can be extremely complicated, suggesting that studies ignoring multiple traits or environments may provide an over-simplified view of the evolution of sexual traits.
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46
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Gershman SN, Toumishey E, Rundle HD. Time flies: Time of day and social environment affect cuticular hydrocarbon sexual displays in Drosophila serrata. Proc Biol Sci 2014; 281:20140821. [PMID: 25143030 PMCID: PMC4150315 DOI: 10.1098/rspb.2014.0821] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2014] [Accepted: 07/23/2014] [Indexed: 11/12/2022] Open
Abstract
Recent work on Drosophila cuticular hydrocarbons (CHCs) challenges a historical assumption that CHCs in flies are largely invariant. Here, we examine the effect of time of day and social environment on a suite of sexually selected CHCs in Drosophila serrata. We demonstrate that males become more attractive to females during the time of day that flies are most active and when most matings occur, but females become less attractive to males during the same time of day. These opposing temporal changes may reflect differences in selection among the sexes. To evaluate the effect of social environment on male CHC attractiveness, we manipulated male opportunity for mating: male flies were housed either alone, with five females, with five males or with five males and five females. We found that males had the most attractive CHCs when with females, and less attractive CHCs when with competitor males. Social environment mediated how male CHC attractiveness cycled: males housed with females and/or other males showed temporal changes in CHC attractiveness, whereas males housed alone did not. In total, our results demonstrate temporal patterning of male CHCs that is dependent on social environment, and suggest that such changes may be beneficial to males.
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Affiliation(s)
- Susan N Gershman
- Department of Biology, University of Ottawa, 30 Marie-Curie Priv., Ottawa, Ontario, Canada K1N 6N5 Department of Evolution, Ecology and Organismal Biology, The Ohio State University at Marion, 1465 Mount Vernon Avenue, Marion, OH 43302, USA
| | - Ethan Toumishey
- Department of Biology, University of Ottawa, 30 Marie-Curie Priv., Ottawa, Ontario, Canada K1N 6N5
| | - Howard D Rundle
- Department of Biology, University of Ottawa, 30 Marie-Curie Priv., Ottawa, Ontario, Canada K1N 6N5
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47
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Simmons LW, Thomas ML, Gray B, Zuk M. Replicated evolutionary divergence in the cuticular hydrocarbon profile of male crickets associated with the loss of song in the Hawaiian archipelago. J Evol Biol 2014; 27:2249-57. [DOI: 10.1111/jeb.12478] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 08/14/2014] [Accepted: 08/14/2014] [Indexed: 02/02/2023]
Affiliation(s)
- L. W. Simmons
- Centre for Evolutionary Biology; School of Animal Biology; The University of Western Australia; Crawley WA Australia
| | - M. L. Thomas
- Centre for Evolutionary Biology; School of Animal Biology; The University of Western Australia; Crawley WA Australia
| | - B. Gray
- Department of Biology; University of California; Riverside CA USA
| | - M. Zuk
- Department of Ecology, Evolution and Behavior; University of Minnesota; St. Paul MN USA
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48
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Gray B, Bailey NW, Poon M, Zuk M. Multimodal signal compensation: do field crickets shift sexual signal modality after the loss of acoustic communication? Anim Behav 2014. [DOI: 10.1016/j.anbehav.2014.04.033] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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49
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Steiger S, Stökl J. The Role of Sexual Selection in the Evolution of Chemical Signals in Insects. INSECTS 2014; 5:423-38. [PMID: 26462692 PMCID: PMC4592599 DOI: 10.3390/insects5020423] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Revised: 05/16/2014] [Accepted: 05/20/2014] [Indexed: 11/16/2022]
Abstract
Chemical communication is the most ancient and widespread form of communication. Yet we are only beginning to grasp the complexity of chemical signals and the role they play in sexual selection. Focusing on insects, we review here the recent progress in the field of olfactory-based sexual selection. We will show that there is mounting empirical evidence that sexual selection affects the evolution of chemical traits, but form and strength of selection differ between species. Studies indicate that some chemical signals are expressed in relation to an individual's condition and depend, for example, on age, immunocompetence, fertility, body size or degree of inbreeding. Males or females might benefit by choosing based on those traits, gaining resources or "good genes". Other chemical traits appear to reliably reflect an individual's underlying genotype and are suitable to choose a mating partner that matches best the own genotype.
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Affiliation(s)
- Sandra Steiger
- Institute of Experimental Ecology, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany.
| | - Johannes Stökl
- Institute of Zoology, University of Regensburg, Universitätstraße 31, 93053 Regensburg, Germany.
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50
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Oliver M, Evans JP. Chemically moderated gamete preferences predict offspring fitness in a broadcast spawning invertebrate. Proc Biol Sci 2014; 281:20140148. [PMID: 24741014 DOI: 10.1098/rspb.2014.0148] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Sperm chemoattraction, where sperm locate unfertilized eggs by following a concentration gradient of egg-derived chemoattractants, has been widely documented across numerous taxa. While marine invertebrates are favoured models for understanding the underlying mechanisms of sperm chemoattraction, the evolutionary forces underpinning the process remain enigmatic. Here, we show that in mussels (Mytilus galloprovincialis), chemically moderated gamete preferences promote assortative fertilizations between genetically compatible gametes. When offered the choice of egg clutches from two females, sperm exhibited consistent but differential 'preferences' for chemical cues secreted from conspecific eggs. Critically, our data reveal that the preferences shown by sperm during the egg-choice trials are highly predictive of early embryonic viability when eggs and sperm from the same individuals are mixed during standard (no-choice) fertilization assays. Moreover, we demonstrate that by experimentally separating chemoattractants from eggs, sperm swimming behaviour is differentially regulated by egg-derived chemoattractants, and that these changes in sperm behaviour are highly consistent with observed patterns of gamete preferences, fertilization and larval survival. Together, this integrated series of experiments reveals that the behaviour of sperm is fine-tuned to respond differentially to the chemical signals emitted from different conspecific eggs, and that these choices have measurable fitness benefits.
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Affiliation(s)
- Mathew Oliver
- Centre for Evolutionary Biology, School of Animal Biology, University of Western Australia, , Crawley, Western Australia 6009, Australia
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