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COSTS AND BENEFITS OF LIFETIME EXPOSURE TO MATING RIVALS IN MALE DROSOPHILA MELANOGASTER
Author(s) -
Bretman Amanda,
Westmancoat James D.,
Gage Matthew J. G.,
Chapman Tracey
Publication year - 2013
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/evo.12125
Subject(s) - biology , mating , competition (biology) , drosophila melanogaster , drosophila (subgenus) , sexual selection , phenotypic plasticity , reproductive success , experimental evolution , longevity , sperm competition , sexual conflict , zoology , ecology , demography , genetics , population , sociology , gene
Theory predicts that males should evolve mechanisms to assess competition and allocate resources accordingly. This requires phenotypic plasticity, to accurately match responses to the environment. Plastic responses in males to sexual competition are diverse and widespread. However, our ability to understand and predict how they evolve is limited because their benefits are rarely measured, and costs are, as yet, entirely unquantified. In the fruit fly Drosophila melanogaster , males that anticipate strong competition for matings or fertilizations subsequently mate for longer and transfer more of two key seminal fluid proteins. This results in significantly elevated reproductive output. In this study, we examined the fitness effects of male responses to rivals across the entire male life span. Males were exposed to rivals or not throughout life while controlling mating opportunities. Males showed significant responses to rivals throughout their lifetimes, associated with significant early‐life fitness benefits. However, these disappeared after the third mating. There were also significant costs—males exposed to rivals took significantly fewer mating opportunities in later life and had significantly shorter life spans than controls. The data suggest that there are substantial costs for males of mounting plastic responses to the threat of sexual competition.