Ram Vasudev

University of Lincoln

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Tom Tregenza

University of Exeter

David J. Hosken

University of Exeter

Paul E. Eady

University of Lincoln

Laurène Gay

Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement

P E Eady

University of Lincoln

Emily Brown

McGill University

Laura Gay

University of Queensland

Daniel Pincheira‐Donoso

Queen's University Belfast

Eric W. Brown

Center for Food Safety and Applied Nutrition

L Gay

University of Utah

Cooperative Institutions

University of Exeter

University of Lincoln

Queen Mary University of London

Diversité, adaptation et développement des plantes

Université de Montpellier

Google (United States)

McGill University

Nanostring Technologies (United States)

University of British Columbia

National Estuarine Research Reserve Association

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The genetic architecture of sexual conflict: male harm and female resistance inCallosobruchus maculatus

Journal of Evolutionary Biology (2010)

Laura Gay Eric W. Brown Tom Tregenza Daniel Pincheira‐Donoso Paul E. Eady

Males harm females during mating in a range of species. This harm is thought to evolve because it is directly or indirectly beneficial to the male, despite being costly to his mate. The resulting sexually antagonistic selection can cause sexual arms races. For sexually antagonistic co-evolution to occur, there must be genetic variation for traits involved in female harming and susceptibility to harm, but even then intersexual genetic correlations could facilitate or impede sexual co-evolution. Male Callosobruchus maculatus harm their mates during copulation by damaging the female's reproductive tract. However, there have been no investigations of the genetic variation in damage or in female susceptibility to damage, nor has the genetic covariance between these characters been assessed. Here, we use a full-sib/half-sib breeding design to show that male damage is heritable, whereas female susceptibility to damage is much less so. There is also a substantial positive genetic correlation between the two, suggesting that selection favouring damaging males will increase the prevalence of susceptible females. We also provide evidence consistent with intralocus sexual conflict in this species.

Callosobruchus maculatus

Genetic Variability

Genetic architecture

10.1111/j.1420-9101.2010.02182.x

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Citations (29)

Does reproductive isolation evolve faster in larger populations via sexually antagonistic coevolution?

Biology Letters (2009)

Laurène Gay Paul E. Eady Ram Vasudev David J. Hosken Tom Tregenza

Sexual conflict over reproductive investment can lead to sexually antagonistic coevolution and reproductive isolation. It has been suggested that, unlike most models of allopatric speciation, the evolution of reproductive isolation through sexually antagonistic coevolution will occur faster in large populations as these harbour greater levels of standing genetic variation, receive larger numbers of mutations and experience more intense sexual selection. We tested this in bruchid beetle populations (Callosobruchus maculatus) by manipulating population size and standing genetic variability in replicated lines derived from founders that had been released from sexual conflict for 90 generations. We found that after 19 generations of reintroduced sexual conflict, none of our treatments had evolved significant overall reproductive isolation among replicate lines. However, as predicted, measures of reproductive isolation tended to be greater among larger populations. We discuss our methodology, arguing that reproductive isolation is best examined by performing a matrix of allopatric and sympatric crosses whereas measurement of divergence requires crosses with a tester line.

Reproductive isolation

Antagonistic Coevolution

Coevolution

Genetic divergence

10.1098/rsbl.2009.0072

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Sperm competition and maternal effects differentially influence testis and sperm size in Callosobruchus maculatus

Journal of Evolutionary Biology (2009)

Laura J. Gay David J. Hosken Ram Vasudev Tom Tregenza Paul E. Eady

The evolutionary factors affecting testis size are well documented, with sperm competition being of major importance. However, the factors affecting sperm length are not well understood; there are no clear theoretical predictions and the empirical evidence is inconsistent. Recently, maternal effects have been implicated in sperm length variation, a finding that may offer insights into its evolution. We investigated potential proximate and microevolutionary factors influencing testis and sperm size in the bruchid beetle Callosobruchus maculatus using a combined approach of an artificial evolution experiment over 90 generations and an environmental effects study. We found that while polyandry seems to select for larger testes, it had no detectable effect on sperm length. Furthermore, population density, a proximate indicator of sperm competition risk, was not significantly associated with sperm length or testis size variation. However, there were strong maternal effects influencing sperm length.

Callosobruchus maculatus

Female sperm storage

10.1111/j.1420-9101.2009.01724.x

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Citations (61)

The evolution of harm – Effect of sexual conflicts and population size

HAL (Le Centre pour la Communication Scientifique Directe) (2010)

Laurène Gay David J. Hosken Paul Eacly Ram Vasudev Tom Tregenza

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Costly sexual harassment in a beetle

Physiological Entomology (2008)

LAURÉNE GAY P E Eady Ram Vasudev David J. Hosken Tom Tregenza

Abstract The optimal number of mating partners for females rarely coincides with that for males, leading to sexual conflict over mating frequency. In the bruchid beetle Callosobruchus maculatus , the fitness consequences to females of engaging in multiple copulations are complex, with studies demonstrating both costs and benefits to multiple mating. However, females kept continuously with males have a lower lifetime egg production compared with females mated only once and then isolated from males. This reduction in fitness may be a result of damage caused by male genitalia, which bear spines that puncture the female’s reproductive tract, and/or toxic elements in the ejaculate. However, male harassment rather than costs of matings themselves could also explain the results. In the present study, the fitness costs of male harassment for female C. maculatus are estimated. The natural refractory period of females immediately after their first mating is used to separate the cost of harassment from the cost of mating. Male harassment results in females laying fewer eggs and this results in a tendency to produce fewer offspring. The results are discussed in the context of mate choice and sexual selection.

Harassment

Antagonistic Coevolution

Callosobruchus maculatus

10.1111/j.1365-3032.2008.00656.x

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Citations (79)

THE EVOLUTION OF HARM-EFFECT OF SEXUAL CONFLICTS AND POPULATION SIZE

Evolution (2010)

Laurène Gay David J. Hosken Paul E. Eady Ram Vasudev Tom Tregenza

Conflicts of interest between mates can promote the evolution of male traits that reduce female fitness and that drive coevolution between the sexes. The rate of adaptation depends on the intensity of selection and its efficiency, which depends on drift and genetic variability. This leads to the largely untested prediction that coevolutionary adaptations such as those driven by sexual conflict should evolve faster in large populations. We tested this using the bruchid beetle Callosobruchus maculatus, a species where harm inflicted by males is well documented. Although most experimental evolution studies remove sexual conflict, we reintroduced it in populations in which it had been experimentally removed. Both population size and standing genetic variability were manipulated in a factorial experimental design. After 90 generations of relaxed conflict (monogamy), the reintroduction of sexual conflicts for 30 generations favored males that harmed females and females that were more resistant to the genital damage inflicted by males. Males evolved to become more harmful when population size was large rather than when initial genetic variation was enriched. Our study shows that sexual selection can create conditions in which males can benefit from harming females and that selection may tend to be more intense and effective in larger populations.

Experimental Evolution

Coevolution

Callosobruchus maculatus

Genetic Variability

Antagonistic Coevolution

Effective population size

10.1111/j.1558-5646.2010.01181.x

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Citations (51)

Negative phenotypic and genetic associations between copulation duration and longevity in male seed beetles

Heredity (2009)

Emily Brown L Gay Ram Vasudev Tom Tregenza P E Eady