scholarly journals The efficacy of sexual selection under environmental change

2018 ◽  
Author(s):  
Ivain Martinossi-Allibert ◽  
Claus Rueffler ◽  
Göran Arnqvist ◽  
David Berger
Keyword(s):  
Sexual Selection ◽  
Environmental Change ◽  
Low Cost ◽  
Empirical Studies ◽  
Fertilization Success ◽  
Honest Signals ◽  
Sexually Selected Traits ◽  
Deleterious Alleles ◽  
Fecundity Selection ◽  
Selected Traits

AbstractSexual selection can promote adaptation if sexually selected traits are reliable indicators of genetic quality. Moreover, stronger sexual selection in males, as often reported in empirical studies, may help purge deleterious alleles at a low cost to population productivity. However, to what extent this remains true when a changing environment affects sexual selection dynamics has been debated. Here, we show that even if sexually selected traits remain honest signals of male quality in new environments, the efficacy of sexual selection will often be reduced under stress. We model the strength of sex-specific selection under different levels of environmental stress in a population in which males compete with each other for fertilization success and in which females experience fecundity selection. We observe that the strength of sexual selection is reduced relative to fecundity selection, resulting in a lowered potential for selection on males to aid adaptation under environmental change.

scholarly journals The efficacy of good genes sexual selection under environmental change

2019 ◽  
Vol 286 (1896) ◽  
pp. 20182313 ◽  
Author(s):  
Ivain Martinossi-Allibert ◽  
Claus Rueffler ◽  
Göran Arnqvist ◽  
David Berger
Keyword(s):  
Sexual Selection ◽  
Environmental Change ◽  
Mating Systems ◽  
Good Genes ◽  
Genetic Quality ◽  
Changing Environments ◽  
Sexually Selected Traits ◽  
Deleterious Alleles ◽  
Selected Traits ◽  
Mechanistic Basis

Sexual selection can promote adaptation if sexually selected traits are reliable indicators of genetic quality. Moreover, models of good genes sexual selection suggest that, by operating more strongly in males than in females, sexual selection may purge deleterious alleles from the population at a low demographic cost, offering an evolutionary benefit to sexually reproducing populations. Here, we investigate the effect of good genes sexual selection on adaptation following environmental change. We show that the strength of sexual selection is often weakened relative to fecundity selection, reducing the suggested benefit of sexual reproduction. This result is a consequence of incorporating a simple and general mechanistic basis for how sexual selection operates under different mating systems, rendering selection on males frequency-dependent and dynamic with respect to the degree of environmental change. Our model illustrates that incorporating the mechanism of selection is necessary to predict evolutionary outcomes and highlights the need to substantiate previous theoretical claims with further work on how sexual selection operates in changing environments.

scholarly journals Sexual selection, phenotypic plasticity and female reproductive output

2019 ◽  
Vol 374 (1768) ◽  
pp. 20180184 ◽  
Author(s):  
Rebecca J. Fox ◽  
Lutz Fromhage ◽  
Michael D. Jennions
Keyword(s):  
Sexual Selection ◽  
Phenotypic Plasticity ◽  
Environmental Change ◽  
Reproductive Output ◽  
Foraging Efficiency ◽  
Phenotypic Variance ◽  
Allocation Of Resources ◽  
Sexually Selected Traits ◽  
Selected Traits ◽  
Rapid Environmental Change

In a rapidly changing environment, does sexual selection on males elevate a population's reproductive output? If so, does phenotypic plasticity enhance or diminish any such effect? We outline two routes by which sexual selection can influence the reproductive output of a population: a genetic correlation between male sexual competitiveness and female lifetime reproductive success; and direct effects of males on females' breeding success. We then discuss how phenotypic plasticity of sexually selected male traits and/or female responses (e.g. plasticity in mate choice), as the environment changes, might influence how sexual selection affects a population's reproductive output. Two key points emerge. First, condition-dependent expression of male sexual traits makes it likely that sexual selection increases female fitness if reproductively successful males disproportionately transfer genes that are under natural selection in both sexes, such as genes for foraging efficiency. Condition-dependence is a form of phenotypic plasticity if some of the variation in net resource acquisition and assimilation is attributable to the environment rather than solely genetic in origin. Second, the optimal allocation of resources into different condition-dependent traits depends on their marginal fitness gains. As male condition improves, this can therefore increase or, though rarely highlighted, actually decrease the expression of sexually selected traits. It is therefore crucial to understand how condition determines male allocation of resources to different sexually selected traits that vary in their immediate effects on female reproductive output (e.g. ornaments versus coercive behaviour). In addition, changes in the distribution of condition among males as the environment shifts could reduce phenotypic variance in certain male traits, thereby reducing the strength of sexual selection imposed by females. Studies of adaptive evolution under rapid environmental change should consider the possibility that phenotypic plasticity of sexually selected male traits, even if it elevates male fitness, could have a negative effect on female reproductive output, thereby increasing the risk of population extinction. This article is part of the theme issue ‘The role of plasticity in phenotypic adaptation to rapid environmental change’.

Urban Sexual Selection

2020 ◽  
pp. 234-252
Author(s):  
Tuul Sepp ◽  
Kevin J. McGraw ◽  
Mathieu Giraudeau
Keyword(s):  
Sexual Selection ◽  
Urban Environments ◽  
Wild Animal ◽  
Selection Pressures ◽  
Sexually Selected Traits ◽  
Chemical Signalling ◽  
Animal Populations ◽  
Challenges And Opportunities ◽  
Microevolutionary Change ◽  
Selected Traits

Human-modified habitats can present both challenges and opportunities for wild animals. Changes in the environment caused by urbanization can affect who survives and reproduces in wild animal populations. Accordingly, we can expect that changes in sexual selection pressures may occur in response to urbanization. Changes in sexually selected traits like bird song and colouration have been one of the main thrusts of urban ecology in recent decades. However, studies to date have focused on describing changes in sexual phenotypes in response to urban environmental change, and knowledge about genetic/microevolutionary change is lacking. Also, while some signalling modalities have been well studied and linked to human activities (e.g., changes in auditory signals in response to anthropogenic noise), others have received comparatively less attention in this context (e.g., effects of air pollution on chemical signalling). In addition, the focus has been mainly on the signal sender, instead of the signal receiver, thereby missing an important side of sexual selection. This chapter reviews the evidence that sexual selection pressures and sexually selected traits have been impacted by urban environments, with attention to the potential for rapid adaptive and plastic shifts in traits of signallers and receivers. It explores the possibilities that urbanization causes evolutionary change and speciation in wild animal populations through sexual selection. Finally, it provides new ideas for future studies to explore these questions and especially the evolution of female preferences in urban environments.

The causes and consequences of ornament variation in a natural population

2019 ◽  
Author(s):  
Annabel Ralph ◽  
Terry Burke ◽  
Shinichi Nakagawa ◽  
Alfredo Sánchez-Tójar ◽  
Julia Schroeder
Keyword(s):  
Sexual Selection ◽  
Evolutionary Biology ◽  
Natural Populations ◽  
Size Variation ◽  
Evolutionary Potential ◽  
House Sparrows ◽  
Sexually Selected Traits ◽  
Evolutionary Response ◽  
Significant Heritability ◽  
Selected Traits

The role of sexual selection in natural populations has long been the subject of debate in evolutionary biology. Ornaments are sexually selected traits, which means they should vary within a population, have a genetic basis, and be associated with fitness. Despite evidence of ornaments meeting these criteria, evolutionary responses to sexual selection are rare in nature. This study focuses on two ornaments in a population of house sparrows; the plumage badge has been well-studied but remains poorly understood and the mask has been largely neglected in the literature. Using quantitative genetic techniques, we estimate the heritability of both traits and test for age-dependency of the heritability estimates. We also estimate the strength and direction of any selection acting upon the traits. We found that both ornaments have low, significant heritability, which does not vary with age. Selection only occurs in a small number of years, although when it does it is positive in both ornaments. We also found that early social environment plays a role in badge size variation. The results of this study suggest that an evolutionary response in the ornaments of this population is unlikely, but we highlight the importance of long-term research to improve our understanding of evolution in natural populations. Studies like these will add to our understanding of sexual selection, the causes of trait variation and the evolutionary potential of traits, which could help us to predict how populations will evolve.

scholarly journals Sexually selected skin colour is heritable and related to fecundity in a non-human primate

2014 ◽  
Vol 281 (1794) ◽  
pp. 20141602 ◽  
Author(s):  
Constance Dubuc ◽  
Sandra Winters ◽  
William L. Allen ◽  
Lauren J. N. Brent ◽  
Julie Cascio ◽  
...  
Keyword(s):  
Sexual Selection ◽  
Individual Variation ◽  
Balancing Selection ◽  
Rhesus Macaques ◽  
Reproductive Rate ◽  
Condition Dependence ◽  
Selection Gradients ◽  
Sexually Selected Traits ◽  
Skin Redness ◽  
Selected Traits

Sexual selection promotes the prevalence of heritable traits that increase an individual's reproductive rate. Despite theoretically strong directional selection, sexually selected traits can show inter-individual variation. Here, we investigate whether red skin ornamentation, a rare example of a male mammalian trait involved in mate attraction, influences fecundity and is heritable in rhesus macaques ( Macaca mulatta ), and explore the mechanisms that are involved in maintaining trait variation. Interestingly, the trait is expressed by and is attractive to both sexes. We collected facial images of 266 free-ranging individuals and modelled skin redness and darkness to rhesus macaque vision. We used 20 years of genetic parentage data to calculate selection gradients on the trait and perform heritability analyses. Results show that males who were both darkly coloured and high-ranking enjoyed higher fecundity. Female skin redness was positively linked to fecundity, although it remains unclear whether this influences male selectiveness. Heritability explained 10–15% of the variation in redness and darkness, and up to 30% for skin darkness when sexes are considered separately, suggesting sex-influenced inheritance. Our results suggest that inter-individual variation is maintained through condition-dependence, with an added effect of balancing selection on male skin darkness, providing rare evidence for a mammalian trait selected through inter-sexual selection.

scholarly journals Rapid courtship evolution in grouse (Tetraonidae): contrasting patterns of acceleration between the Eurasian and North American polygynous clades

2007 ◽  
Vol 274 (1613) ◽  
pp. 1079-1086 ◽  
Author(s):  
Allen Spaulding
Keyword(s):  
Sexual Selection ◽  
Mating Success ◽  
Male Mating ◽  
Sexually Dimorphic ◽  
Sexually Selected Traits ◽  
Species Pairs ◽  
Rapid Divergence ◽  
Nucleotide Divergence ◽  
Selected Traits ◽  
Dimorphic Species

Sexual selection is thought to be a powerful diversifying force, based on large ornamental differences between sexually dimorphic species. This assumes that unornamented phenotypes represent evolution without sexual selection. If sexual selection is more powerful than other forms of selection, then two effects would be: rapid divergence of sexually selected traits and a correlation between these divergence rates and variance in mating success in the ornamented sex. I tested for these effects in grouse (Tetraonidae). For three species pairs, within and among polygynous clades, male courtship characters had significantly greater divergence than other characters. This was most pronounced for two species in Tympanuchus . In the Eurasian polygynous clade, relative courtship divergence gradually increased with nucleotide divergence, suggesting a less dramatic acceleration. Increase in relative courtship divergence was associated with mating systems having higher variance in male mating success. These results suggest that sexual selection has accelerated courtship evolution among grouse, although the microevolutionary details appear to vary among clades.

scholarly journals Female preference for multi-modal courtship: multiple signals are important for male mating success in peacock spiders

2015 ◽  
Vol 282 (1820) ◽  
pp. 20152222 ◽  
Author(s):  
Madeline B. Girard ◽  
Damian O. Elias ◽  
Michael M. Kasumovic
Keyword(s):  
Sexual Selection ◽  
Mating Success ◽  
Female Preference ◽  
Male Mating ◽  
Sexually Dimorphic ◽  
Complex Signals ◽  
Sexually Selected Traits ◽  
Redundant Signal ◽  
Multiple Messages ◽  
Selected Traits

A long-standing goal for biologists has been to understand how female preferences operate in systems where males have evolved numerous sexually selected traits. Jumping spiders of the Maratus genus are exceptionally sexually dimorphic in appearance and signalling behaviour. Presumably, strong sexual selection by females has played an important role in the evolution of complex signals displayed by males of this group; however, this has not yet been demonstrated. In fact, despite apparent widespread examples of sexual selection in nature, empirical evidence is relatively sparse, especially for species employing multiple modalities for intersexual communication. In order to elucidate whether female preference can explain the evolution of multi-modal signalling traits, we ran a series of mating trials using Maratus volans . We used video recordings and laser vibrometry to characterize, quantify and examine which male courtship traits predict various metrics of mating success. We found evidence for strong sexual selection on males in this system, with success contingent upon a combination of visual and vibratory displays. Additionally, independently produced, yet correlated suites of multi-modal male signals are linked to other aspects of female peacock spider behaviour. Lastly, our data provide some support for both the redundant signal and multiple messages hypotheses for the evolution of multi-modal signalling.

scholarly journals Mating system and brain size in bats

2005 ◽  
Vol 273 (1587) ◽  
pp. 719-724 ◽  
Author(s):  
Scott Pitnick ◽  
Kate E Jones ◽  
Gerald S Wilkinson
Keyword(s):  
Sexual Selection ◽  
Mating System ◽  
Multiple Mating ◽  
Brain Size ◽  
Evolutionary Relationship ◽  
Brain Evolution ◽  
Correlated Evolution ◽  
Mate Fidelity ◽  
Sexually Selected Traits ◽  
Selected Traits

The contribution of sexual selection to brain evolution has been little investigated. Through comparative analyses of bats, we show that multiple mating by males, in the absence of multiple mating by females, has no evolutionary impact on relative brain dimension. In contrast, bat species with promiscuous females have relatively smaller brains than do species with females exhibiting mate fidelity. This pattern may be a consequence of the demonstrated negative evolutionary relationship between investment in testes and investment in brains, both metabolically expensive tissues. These results have implications for understanding the correlated evolution of brains, behaviour and extravagant sexually selected traits.

scholarly journals Intraspecific sperm competition genes enforce post-mating species barriers in Drosophila

2014 ◽  
Vol 281 (1797) ◽  
pp. 20142050 ◽  
Author(s):  
Dean M. Castillo ◽  
Leonie C. Moyle
Keyword(s):  
Sexual Selection ◽  
Reproductive Isolation ◽  
Sperm Competition ◽  
Competitive Ability ◽  
Sexual Isolation ◽  
Theoretical Models ◽  
Sexually Selected Traits ◽  
Genetic Mechanisms ◽  
Selected Traits ◽  
Additional Role

Sexual selection and sexual conflict are considered important drivers of speciation, based on both theoretical models and empirical correlations between sexually selected traits and diversification. However, whether reproductive isolation between species evolves directly as a consequence of intrapopulation sexual dynamics remains empirically unresolved, in part because knowledge of the genetic mechanisms (if any) connecting these processes is limited. Here, we provide evidence of a direct mechanistic link between intraspecies sexual selection and reproductive isolation. We examined genes with known roles in intraspecific sperm competition (ISC) in D. melanogaster and assayed their impact on conspecific sperm precedence (CSP). We found that two such genes ( Acp36DE and CG9997 ) contribute to both offensive sperm competition and CSP; null/knockdown lines both had lower competitive ability against D. melanogaster conspecifics and were no longer able to displace heterospecific D. simulans sperm in competitive matings. In comparison, Sex Peptide ( Acp70A )—another locus essential for ISC—does not contribute to CSP. These data indicate that two loci important for sperm competitive interactions have an additional role in similar interactions that enforce post-mating reproductive isolation between species, and show that sexual selection and sexual isolation can act on the same molecular targets in a gene-specific manner.

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