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Rusuwa BB, Chung H, Allen SL, Frentiu FD, Chenoweth SF. Natural variation at a single gene generates sexual antagonism across fitness components in Drosophila. Curr Biol 2022; 32:3161-3169.e7. [PMID: 35700732 DOI: 10.1016/j.cub.2022.05.038] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 04/19/2022] [Accepted: 05/13/2022] [Indexed: 12/30/2022]
Abstract
Mutations with conflicting fitness effects in males and females accumulate in sexual populations, reducing their adaptive capacity.1,2 Although quantitative genetic studies indicate that sexually antagonistic polymorphisms are common,3-5 their molecular basis and population genetic properties remain poorly understood.6,7 Here, we show in fruit flies how natural variation at a single gene generates sexual antagonism through phenotypic effects on cuticular hydrocarbon (CHC) traits that function as both mate signals and protectors against abiotic stress8 across a latitudinal gradient. Tropical populations of Drosophila serrata have polymorphic CHCs producing sexual antagonism through opposing but sex-limited effects on these two fitness-related functions. We dissected this polymorphism to a single fatty-acyl CoA reductase gene, DsFAR2-B, that is expressed in oenocyte cells where CHCs are synthesized. RNAi-mediated disruption of the DsFAR2-B ortholog in D. melanogaster oenocytes affected CHCs in a similar way to that seen in D. serrata. Population genomic analysis revealed that balancing selection likely operates at the DsFAR2-B locus in the wild. Our study provides insights into the genetic basis of sexual antagonism in nature and connects sexually varying antagonistic selection on phenotypes with balancing selection on genotypes that maintains molecular variation.
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Affiliation(s)
- Bosco B Rusuwa
- School of Biological Sciences, The University of Queensland, St Lucia, Australia; Department of Biological Sciences, Chancellor College, University of Malawi, Zomba, Malawi
| | - Henry Chung
- Department of Entomology and Ecology, Evolution, and Behavior Program, Michigan State University, East Lansing, MI, USA
| | - Scott L Allen
- School of Biological Sciences, The University of Queensland, St Lucia, Australia
| | - Francesca D Frentiu
- School of Biological Sciences, The University of Queensland, St Lucia, Australia; School of Biomedical Sciences, Queensland University of Technology, Brisbane, QLD 4001, Australia
| | - Stephen F Chenoweth
- School of Biological Sciences, The University of Queensland, St Lucia, Australia.
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2
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Martin JO, Burley NT. Elucidating mutual mate choice: effects of trial design on preferences of male zebra finches. Behav Ecol 2021. [DOI: 10.1093/beheco/arab097] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Understanding the dynamics of mutual mate choice requires investigation of mate preferences of both sexes using a variety of designs, but fewer studies have focused on male choice in avian models. Here we conducted two experiments on preferences of male zebra finches to study the impact of trial design on results. Experimental design varied in number of trial participants, inclusion of observer (“audience”) males, and housing design for stimulus females. Females were reared on one of two diets to enhance variation in mating quality: those reared on a protein-supplement diet (HI-diet) were predicted to be more attractive to males than (LO-diet) females that did not receive supplements. Results differed among trial types. Notably, males showed the predicted preference for HI-diet females only in the Group Choice experiment, where two male subjects simultaneously chose from a field of four females, and all six birds interacted freely. In the Dyadic Preference (DP) experiment, a single male was allowed to interact with two stimulus females that were physically isolated; in half of these trials, audience males were present. In DP trials without audience males, test males did not express a preference consensus; however, with audience males present, test males preferred LO-diet females. Results are consistent with a small but growing literature indicating that results of mate choice experiments can be highly sensitive to design considerations.
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Affiliation(s)
- John O Martin
- Department of Ecology and Evolutionary Biology, 321 Steinhaus Hall, University of California, Irvine, Irvine CA, USA
| | - Nancy Tyler Burley
- Department of Ecology and Evolutionary Biology, 321 Steinhaus Hall, University of California, Irvine, Irvine CA, USA
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3
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Gershman SN. Mating has opposite effects on male and female sexually selected cuticular hydrocarbons. Anim Behav 2020. [DOI: 10.1016/j.anbehav.2020.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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4
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Berson JD, Simmons LW. Female cuticular hydrocarbons can signal indirect fecundity benefits in an insect. Evolution 2019; 73:982-989. [DOI: 10.1111/evo.13720] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 03/09/2019] [Indexed: 11/30/2022]
Affiliation(s)
- Jacob D. Berson
- Centre for Evolutionary Biology, School of Biological SciencesThe University of Western Australia Crawley Western Australia 6009 Australia
| | - Leigh W. Simmons
- Centre for Evolutionary Biology, School of Biological SciencesThe University of Western Australia Crawley Western Australia 6009 Australia
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5
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Siepielski AM, McPeek SJ, McPeek MA. Female mate preferences on high-dimensional shape variation for male species recognition traits. J Evol Biol 2018; 31:1239-1250. [PMID: 29876989 DOI: 10.1111/jeb.13302] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 05/14/2018] [Accepted: 05/31/2018] [Indexed: 01/01/2023]
Abstract
Females in many animal species must discriminate between conspecific and heterospecific males when choosing mates. Such mating preferences that discriminate against heterospecifics may inadvertently also affect the mating success of conspecific males, particularly those with more extreme phenotypes. From this expectation, we hypothesized that female mate choice should cause Enallagma females (Odonata: Coenagrionidae) to discriminate against conspecific males with more extreme phenotypes of the claspers males use to grasp females while mating - the main feature of species mate recognition in these species. To test this, we compared cerci sizes and shapes between males that were captured while mating with females to males that were captured at the same time but not mating in three Enallagma species. In contrast to our hypothesis, we found only one of forty comparisons of shape variation that was consistent with females discriminating against males with more extreme cerci shapes. Instead, differences in cerci shape between mating and single males suggested that females displayed directional preferences on 1-4 aspects of cerci shape in two of the species in our samples. These results suggest that whereas some directional biases in mating based on cerci shape occur, the intraspecific phenotypic variation in male cerci size and shape is likely not large enough for females to express any significant incidental discrimination among conspecifics with more extreme shapes.
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Affiliation(s)
- Adam M Siepielski
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR, USA
| | - Sarah J McPeek
- Department of Biological Sciences, Dartmouth College, Hanover, NH, USA
| | - Mark A McPeek
- Department of Biological Sciences, Dartmouth College, Hanover, NH, USA
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6
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Artificial selection reveals sex differences in the genetic basis of sexual attractiveness. Proc Natl Acad Sci U S A 2018; 115:5498-5503. [PMID: 29735676 DOI: 10.1073/pnas.1720368115] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Mutual mate choice occurs when males and females base mating decisions on shared traits. Despite increased awareness, the extent to which mutual choice drives phenotypic change remains poorly understood. When preferences in both sexes target the same traits, it is unclear how evolution will proceed and whether responses to sexual selection from male choice will match or oppose responses to female choice. Answering this question is challenging, as it requires understanding, genetic relationships between the traits targeted by choice, mating success, and, ultimately, fitness for both sexes. Addressing this, we applied artificial selection to the cuticular hydrocarbons of the fly Drosophila serrata that are targeted by mutual choice and tracked evolutionary changes in males and females alongside changes in mating success. After 10 generations, significant trait evolution occurred in both sexes, but intriguingly there were major sex differences in the associated fitness consequences. Sexually selected trait evolution in males led to a genetically based increase in male mating success. By contrast, although trait evolution also occurred in females, there was no change in mating success. Our results suggest that phenotypic sexual selection on females from male choice is environmentally, rather than genetically, generated. Thus, compared with female choice, male choice is at best a weak driver of signal trait evolution in this species. Instead, the evolution of apparent female ornamentation seems more likely due to a correlated response to sexual selection on males and possibly other forms of natural selection.
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7
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De Lisle SP, Svensson EI. On the standardization of fitness and traits in comparative studies of phenotypic selection. Evolution 2017; 71:2313-2326. [PMID: 28804878 DOI: 10.1111/evo.13325] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 08/03/2017] [Indexed: 02/02/2023]
Abstract
Comparisons of the strength and form of phenotypic selection among groups provide a powerful approach for testing adaptive hypotheses. A central and largely unaddressed issue is how fitness and phenotypes are standardized in such studies; standardization across or within groups can qualitatively change conclusions whenever mean fitness differs between groups. We briefly reviewed recent relevant literature, and found that selection studies vary widely in their scale of standardization, but few investigators motivated their rationale for chosen standardization approaches. Here, we propose that the scale at which fitness should be relativized should reflect whether selection is likely to be hard or soft; that is, the scale at which populations (or hypothetical populations in the case of a contrived experiment) are regulated. We argue that many comparative studies of selection are implicitly or explicitly focused on soft selection (i.e., frequency and density-dependent selection). In such studies, relative fitness should preferably be calculated using within-group means, although this approach is taken only occasionally. Related difficulties arise for the standardization of phenotypes. The appropriate scale at which standardization should take place depends on whether groups are considered to be fixed or random. We emphasize that the scale of standardization is a critical decision in empirical studies of selection that should always warrant explicit justification.
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Affiliation(s)
- Stephen P De Lisle
- Evolutionary Ecology Unit, Department of Biology, Lund University, Sölvegatan 37, 223 62 Lund, Sweden
| | - Erik I Svensson
- Evolutionary Ecology Unit, Department of Biology, Lund University, Sölvegatan 37, 223 62 Lund, Sweden
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8
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Booksmythe I, Rundle HD, Arnqvist G. Sexual dimorphism in epicuticular compounds despite similar sexual selection in sex role-reversed seed beetles. J Evol Biol 2017; 30:2005-2016. [DOI: 10.1111/jeb.13171] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 07/28/2017] [Accepted: 08/20/2017] [Indexed: 01/06/2023]
Affiliation(s)
- I. Booksmythe
- Department of Evolutionary Biology and Environmental Studies; University of Zurich; Zurich Switzerland
| | - H. D. Rundle
- Department of Biology; University of Ottawa; Ottawa ON Canada
| | - G. Arnqvist
- Department of Animal Ecology; Evolutionary Biology Centre; Uppsala University; Uppsala Sweden
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9
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Ercit K, Gwynne DT. A novel method of comparing mating success and survival reveals similar sexual and viability selection for mobility traits in female tree crickets. J Evol Biol 2016; 29:1189-200. [DOI: 10.1111/jeb.12860] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 03/08/2016] [Accepted: 03/09/2016] [Indexed: 11/29/2022]
Affiliation(s)
- K. Ercit
- Department of Ecology and Evolutionary Biology; University of Toronto at Mississauga; Mississauga ON Canada
| | - D. T. Gwynne
- Department of Ecology and Evolutionary Biology; University of Toronto at Mississauga; Mississauga ON Canada
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10
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Gosden TP, Thomson JR, Blows MW, Schaul A, Chenoweth SF. Testing for a genetic response to sexual selection in a wild
Drosophila
population. J Evol Biol 2016; 29:1278-83. [DOI: 10.1111/jeb.12851] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 02/17/2016] [Accepted: 02/18/2016] [Indexed: 11/27/2022]
Affiliation(s)
- T. P. Gosden
- School of Biological Sciences The University of Queensland St. Lucia Qld Australia
| | - J. R. Thomson
- School of Biological Sciences The University of Queensland St. Lucia Qld Australia
| | - M. W. Blows
- School of Biological Sciences The University of Queensland St. Lucia Qld Australia
| | - A. Schaul
- School of Biological Sciences The University of Queensland St. Lucia Qld Australia
| | - S. F. Chenoweth
- School of Biological Sciences The University of Queensland St. Lucia Qld Australia
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11
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Gershman SN, Rundle HD. Level up: the expression of male sexually selected cuticular hydrocarbons is mediated by sexual experience. Anim Behav 2016. [DOI: 10.1016/j.anbehav.2015.11.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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12
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Fitzpatrick CL, Altmann J, Alberts SC. Exaggerated sexual swellings and male mate choice in primates: testing the reliable indicator hypothesis in the Amboseli baboons. Anim Behav 2015; 104:175-185. [PMID: 26752790 PMCID: PMC4704114 DOI: 10.1016/j.anbehav.2015.03.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The paradigm of competitive males vying to influence female mate choice has been repeatedly upheld, but, increasingly, studies also report competitive females and choosy males. One female trait that is commonly proposed to influence male mate choice is the exaggerated sexual swelling displayed by females of many Old World primate species. The reliable indicator hypothesis posits that females use the exaggerated swellings to compete for access to mates, and that the swellings advertise variation in female fitness. We tested the two main predictions of this hypothesis in a wild population of baboons (Papio cynocephalus). First, we examined the effect of swelling size on the probability of mate-guarding ('consortship') by the highest-ranking male and the behavior of those males that trailed consorshipts ('follower males'). Second, we asked whether a female's swelling size predicted several fitness measures. We found that high-ranking males do not prefer females with larger swellings (when controlling for cycle number and conception) and that females with larger swellings did not have higher reproductive success. Our study-the only complete test of the reliable indicator hypothesis in a primate population-rejects the idea that female baboons compete for mates by advertising heritable fitness differences. Furthermore, we found unambiguous evidence that males biased their mating decisions in favor of females who had experienced more sexual cycles since their most recent pregnancy. Thus, rather than tracking the potential differences in fitness between females, male baboons appear to track and target the potential for a given reproductive opportunity to result in fertilization.
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Affiliation(s)
| | - Jeanne Altmann
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA; National Museums of Kenya, Institute of Primate Research, Nairobi, Kenya
| | - Susan C Alberts
- Department of Biology, Duke University, Durham, NC, USA; National Museums of Kenya, Institute of Primate Research, Nairobi, Kenya
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13
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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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14
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Gosden TP, Rundle HD, Chenoweth SF. Testing the correlated response hypothesis for the evolution and maintenance of male mating preferences in Drosophila serrata. J Evol Biol 2014; 27:2106-12. [DOI: 10.1111/jeb.12461] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 07/09/2014] [Accepted: 07/09/2014] [Indexed: 11/29/2022]
Affiliation(s)
- T. P. Gosden
- School of Biological Sciences; The University of Queensland; Brisbane Qld Australia
- Section for Evolutionary Ecology; Department of Biology; Lund University; Lund Sweden
| | - H. D. Rundle
- Department of Biology; University of Ottawa; Ottawa ON Canada
| | - S. F. Chenoweth
- School of Biological Sciences; The University of Queensland; Brisbane Qld Australia
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15
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Ingleby FC, Innocenti P, Rundle HD, Morrow EH. Between-sex genetic covariance constrains the evolution of sexual dimorphism in Drosophila melanogaster. J Evol Biol 2014; 27:1721-32. [PMID: 24893565 DOI: 10.1111/jeb.12429] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 04/29/2014] [Accepted: 05/05/2014] [Indexed: 11/27/2022]
Abstract
Males and females share much of their genome, and as a result, intralocus sexual conflict is generated when selection on a shared trait differs between the sexes. This conflict can be partially or entirely resolved via the evolution of sex-specific genetic variation that allows each sex to approach, or possibly achieve, its optimum phenotype, thereby generating sexual dimorphism. However, shared genetic variation between the sexes can impose constraints on the independent expression of a shared trait in males and females, hindering the evolution of sexual dimorphism. Here, we examine genetic constraints on the evolution of sexual dimorphism in Drosophila melanogaster cuticular hydrocarbon (CHC) expression. We use the extended G matrix, which includes the between-sex genetic covariances that constitute the B matrix, to compare genetic constraints on two sets of CHC traits that differ in the extent of their sexual dimorphism. We find significant genetic constraints on the evolution of further dimorphism in the least dimorphic traits, but no such constraints for the most dimorphic traits. We also show that the genetic constraints on the least dimorphic CHCs are asymmetrical between the sexes. Our results suggest that there is evidence both for resolved and ongoing sexual conflict in D. melanogaster CHC profiles.
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Affiliation(s)
- F C Ingleby
- Evolution, Behaviour and Environment Group, School of Life Sciences, University of Sussex, John Maynard Smith Building, Falmer, Brighton, UK
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16
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Gershman S, Delcourt M, Rundle HD. Sexual selection on Drosophila serrata
male pheromones does not vary with female age or mating status. J Evol Biol 2014; 27:1279-86. [DOI: 10.1111/jeb.12407] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 03/02/2014] [Accepted: 03/25/2014] [Indexed: 11/30/2022]
Affiliation(s)
- S. Gershman
- Department of Biology; University of Ottawa; Ottawa ON Canada
- Department of Evolution; Ecology and Organismal Biology; The Ohio State University at Marion; OH USA
| | - M. Delcourt
- Department of Biology; University of Ottawa; Ottawa ON Canada
| | - H. D. Rundle
- Department of Biology; University of Ottawa; Ottawa ON Canada
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17
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Gosden TP, Chenoweth SF. The evolutionary stability of cross-sex, cross-trait genetic covariances. Evolution 2014; 68:1687-97. [PMID: 24620712 DOI: 10.1111/evo.12398] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 02/24/2014] [Indexed: 11/30/2022]
Abstract
Although knowledge of the selective agents behind the evolution of sexual dimorphism has advanced considerably in recent years, we still lack a clear understanding of the evolutionary durability of cross-sex genetic covariances that often constrain its evolution. We tested the relative stability of cross-sex genetic covariances for a suite of homologous contact pheromones of the fruit fly Drosophila serrata, along a latitudinal gradient where these traits have diverged in mean. Using a Bayesian framework, which allowed us to account for uncertainty in all parameter estimates, we compared divergence in the total amount and orientation of genetic variance across populations, finding divergence in orientation but not total variance. We then statistically compared orientation divergence of within-sex (G) to cross-sex (B) covariance matrices. In line with a previous theoretical prediction, we find that the cross-sex covariance matrix, B, is more variable than either within-sex G matrix. Decomposition of B matrices into their symmetrical and nonsymmetrical components revealed that instability is linked to the degree of asymmetry. We also find that the degree of asymmetry correlates with latitude suggesting a role for spatially varying natural selection in shaping genetic constraints on the evolution of sexual dimorphism.
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Affiliation(s)
- Thomas P Gosden
- School of Biological Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia; Section for Evolutionary Ecology, Department of Biology, Lund University, Sölvegatan 37, 223 62 Lund, Sweden.
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18
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Wyman MJ, Stinchcombe JR, Rowe L. A multivariate view of the evolution of sexual dimorphism. J Evol Biol 2014; 26:2070-80. [PMID: 24028470 DOI: 10.1111/jeb.12188] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 04/08/2013] [Accepted: 04/12/2013] [Indexed: 12/31/2022]
Abstract
Sexual differences are often dramatic and widespread across taxa. Their extravagance and ubiquity can be puzzling because the common underlying genome of males and females is expected to impede rather than foster phenotypic divergence. Widespread dimorphism, despite a shared genome, may be more readily explained by considering the multivariate, rather than univariate, framework governing the evolution of sexual dimorphism. In the univariate formulation, differences in genetic variances and a low intersexual genetic correlation (rMF) can facilitate the evolution of sexual dimorphism. However, studies that have analysed sex-specific differences in heritabilities or genetic variances do not always find significant differences. Furthermore, many of the reported estimates of rMF are very high and positive. When monomorphic heritabilities and a high rMF are present together, the evolution of sexual dimorphism on a trait-by-trait basis is severely constrained. By contrast, the multivariate formulation has greater generality and more flexibility. Although the number of multivariate sexual dimorphism studies is low, almost all support sex-specific differences in the G (variance-covariance) matrix; G matrices can differ with respect to size and/or orientation, affecting the response to selection differently between the sexes. Second, whereas positive values of the univariate quantity rMF only hinder positive changes in sexual dimorphism, positive covariances in the intersexual covariance B matrix can either help or hinder. Similarly, the handful of studies reporting B matrices indicate that it is often asymmetric, so that B can affect the evolution of single traits differently between the sexes. Multivariate approaches typically demonstrate that genetic covariances among traits can strongly constrain trait evolution when compared with univariate approaches. By contrast, in the evolution of sexual dimorphism, a multivariate view potentially reveals more opportunities for sexual dimorphism to evolve by considering the effect sex-specific selection has on sex-specific G matrices and an asymmetric B matrix.
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Affiliation(s)
- M J Wyman
- Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, ON, Canada
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19
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Dyer KA, White BE, Sztepanacz JL, Bewick ER, Rundle HD. Reproductive character displacement of epicuticular compounds and their contribution to mate choice in Drosophila subquinaria and Drosophila recens. Evolution 2014; 68:1163-75. [PMID: 24351014 PMCID: PMC4278427 DOI: 10.1111/evo.12335] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Accepted: 12/03/2013] [Indexed: 11/29/2022]
Abstract
Interactions between species can alter selection on sexual displays used in mate choice within species. Here we study the epicuticular pheromones of two Drosophila species that overlap partially in geographic range and are incompletely reproductively isolated. Drosophila subquinaria shows a pattern of reproductive character displacement against Drosophila recens, and partial behavioral isolation between conspecific sympatric versus allopatric populations, whereas D. recens shows no such variation in mate choice. First, using manipulative perfuming experiments, we show that females use pheromones as signals for mate discrimination both between species and among populations of D. subquinaria. Second, we show that patterns of variation in epicuticular compounds, both across populations and between species, are consistent with those previously shown for mating probabilities: pheromone compositions differ between populations of D. subquinaria that are allopatric versus sympatric with D. recens, but are similar across populations of D. recens regardless of overlap with D. subquinaria. We also identify differences in pheromone composition among allopatric regions of D. subquinaria. In sum, our results suggest that epicuticular compounds are key signals used by females during mate recognition, and that these traits have diverged among D. subquinaria populations in response to reinforcing selection generated by the presence of D. recens.
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Affiliation(s)
- Kelly A Dyer
- Department of Genetics, University of Georgia, Athens, Georgia, 30602.
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20
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Gosden TP, Shastri KL, Innocenti P, Chenoweth SF. The B-matrix harbors significant and sex-specific constraints on the evolution of multicharacter sexual dimorphism. Evolution 2012; 66:2106-16. [PMID: 22759288 DOI: 10.1111/j.1558-5646.2012.01579.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The extent to which sexual dimorphism can evolve within a population depends on an interaction between sexually divergent selection and constraints imposed by a genetic architecture that is shared between males and females. The degree of constraint within a population is normally inferred from the intersexual genetic correlation, r(mf) . However, such bivariate correlations ignore the potential constraining effect of genetic covariances between other sexually coexpressed traits. Using the fruit fly Drosophila serrata, a species that exhibits mutual mate preference for blends of homologous contact pheromones, we tested the impact of between-sex between-trait genetic covariances using an extended version of the genetic variance-covariance matrix, G, that includes Lande's (1980) between-sex covariance matrix, B. We find that including B greatly reduces the degree to which male and female traits are predicted to diverge in the face of divergent phenotypic selection. However, the degree to which B alters the response to selection differs between the sexes. The overall rate of male trait evolution is predicted to decline, but its direction remains relatively unchanged, whereas the opposite is found for females. We emphasize the importance of considering the B-matrix in microevolutionary studies of constraint on the evolution of sexual dimorphism.
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Affiliation(s)
- Thomas P Gosden
- School of Biological Sciences, The University of Queensland, Brisbane QLD 4072, Australia.
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Sztepanacz JL, Rundle HD. Reduced genetic variance among high fitness individuals: inferring stabilizing selection on male sexual displays in Drosophila serrata. Evolution 2012; 66:3101-10. [PMID: 23025601 DOI: 10.1111/j.1558-5646.2012.01658.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Directional selection is prevalent in nature, yet phenotypes tend to remain relatively constant, suggesting a limit to trait evolution. However, the genetic basis of this limit is unresolved. Given widespread pleiotropy, opposing selection on a trait may arise from the effects of the underlying alleles on other traits under selection, generating net stabilizing selection on trait genetic variance. These pleiotropic costs of trait exaggeration may arise through any number of other traits, making them hard to detect in phenotypic analyses. Stabilizing selection can be inferred, however, if genetic variance is greater among low- compared to high-fitness individuals. We extend a recently suggested approach to provide a direct test of a difference in genetic variance for a suite of cuticular hydrocarbons (CHCs) in Drosophila serrata. Despite strong directional sexual selection on these traits, genetic variance differed between high- and low-fitness individuals and was greater among the low-fitness males for seven of eight CHCs, significantly more than expected by chance. Univariate tests of a difference in genetic variance were nonsignificant but likely have low power. Our results suggest that further CHC exaggeration in D. serrata in response to sexual selection is limited by pleiotropic costs mediated through other traits.
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WHEELER J, GWYNNE DT, BUSSIÈRE LF. Stabilizing sexual selection for female ornaments in a dance fly. J Evol Biol 2012; 25:1233-42. [DOI: 10.1111/j.1420-9101.2012.02522.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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BEDHOMME STÉPHANIE, CHIPPINDALE ADAMK, PRASAD NG, DELCOURT MATTHIEU, ABBOTT JESSICAK, MALLET MARTINA, RUNDLE HOWARDD. Male-limited evolution suggests no extant intralocus sexual conflict over the sexually dimorphic cuticular hydrocarbons of Drosophila melanogaster. J Genet 2011; 90:443-52. [DOI: 10.1007/s12041-011-0109-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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The evolution and significance of male mate choice. Trends Ecol Evol 2011; 26:647-54. [PMID: 21890230 DOI: 10.1016/j.tree.2011.07.012] [Citation(s) in RCA: 363] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Revised: 07/25/2011] [Accepted: 07/26/2011] [Indexed: 11/22/2022]
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