Sexual selection shapes development and maturation rates in Drosophila |
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Authors: | Brian Hollis Laurent Keller Tadeusz J. Kawecki |
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Affiliation: | 1. School of Life Sciences, école Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland;2. Department of Ecology and Evolution, University of Lausanne, Biophore, Lausanne, Switzerland |
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Abstract: | Explanations for the evolution of delayed maturity usually invoke trade‐offs mediated by growth, but processes of reproductive maturation continue long after growth has ceased. Here, we tested whether sexual selection shapes the rate of posteclosion maturation in the fruit fly Drosophila melanogaster. We found that populations maintained for more than 100 generations under a short generation time and polygamous mating system evolved faster posteclosion maturation and faster egg‐to‐adult development of males, when compared to populations kept under short generations and randomized monogamy that eliminated sexual selection. An independent assay demonstrated that more mature males have higher fitness under polygamy, but this advantage disappears under monogamy. In contrast, for females greater maturity was equally advantageous under polygamy and monogamy. Furthermore, monogamous populations evolved faster development and maturation of females relative to polygamous populations, with no detectable trade‐offs with adult size or egg‐to‐adult survival. These results suggest that a major aspect of male maturation involves developing traits that increase success in sexual competition, whereas female maturation is not limited by investment in traits involved in mate choice or defense against male antagonism. Moreover, rates of juvenile development and adult maturation can readily evolve in opposite directions in the two sexes, possibly implicating polymorphisms with sexually antagonistic pleiotropy. |
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Keywords: | Development Drosophila melanogaster experimental evolution maturation sexual dimorphism sexual selection |
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