The role of pre- and post-mating sexual selection on trait evolution: from ejaculates to behaviour
Sensory and Behavioural Biology
Final Report Abstract
This DFG project contributed to advancing our understanding on how pre- and postcopulatory sexual selection interact to shape the evolutionary diversification of reproductive traits (behaviour, morphology, and ejaculates) that give rise to complex male reproductive phenotypes. The project focused on the field cricket Gryllus bimaculatus, an insect model with a very well-characterized mating system, and led to the following key findings. 1) By adopting a unique design that exclusively allows pre-copulatory selection, post-copulatory selection, and weakened sexual selection we show that regardless of whether occurring preor post-copulatory, sexual selection enhances female fitness. This highlights its role in potentially maintaining population viability. 2) When allowing animals to evolve for several generations under these exclusive pre- and post-copulatory selective regimes we document rapid divergence of multiple pre- and post-copulatory reproductive traits. Overall, precopulatory selection elicited increased pre-copulatory trait values (e.g., males evolving higher body mass) while post-copulatory selection negative post-copulatory trait values (e.g., males evolving smaller testes), highlighting complex trait responses. 3) By employing a quantitative genetic approach and estimating within- and cross-sex genetic architecture (including indirect genetic effects, IGEs) of multiple pre- and post-copulatory sexual traits we show that successful reproductive phenotypes are the result of multiple traits with interacting genetic effects. Taken together, we acknowledge the potential beneficial population-level consequences of sexual selection, and stress how the action of each selective episode, preand post-copulatory, can shape multiple interacting reproductive traits, key in mate choice evolution. This project further highlights the importance of adopting a comprehensive and yet highly demanding multi-trait approach to fully understand what drives the evolution of sexually selected phenotypes.
Publications
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Food Limitation but Not Enhanced Rates of Ejaculate Production Imposes Reproductive and Survival Costs to Male Crickets. Cells, 10(6), 1498.
McMahon, Saoirse; Matzke, Magdalena & Tuni, Cristina
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Pre‐ and post‐copulatory sexual selection increase offspring quality but impose survival costs to female field crickets. Journal of Evolutionary Biology, 36(1), 296-308.
Matzke, Magdalena; Rossi, Aurora & Tuni, Cristina
