REMATING IN DROSOPHILA MELANOGASTER: ARE INDIRECT BENEFITS CONDITION DEPENDENT?

Authors

  • Tristan A. F. Long,

    1. Department of Ecology, Evolution & Marine Biology, Life Sciences Building, University of Santa Barbara, Santa Barbara, California 93106
    2. E-mail: tristan.long@utoronto.ca
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    • Present address: Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario M5S 3B2, Canada.

  • Alison Pischedda,

    1. Department of Ecology, Evolution & Marine Biology, Life Sciences Building, University of Santa Barbara, Santa Barbara, California 93106
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  • William R. Rice

    1. Department of Ecology, Evolution & Marine Biology, Life Sciences Building, University of Santa Barbara, Santa Barbara, California 93106
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Abstract

By measuring the direct and indirect fitness costs and benefits of sexual interactions, the feasibility of alternate explanations for polyandry can be experimentally assessed. This approach becomes more complicated when the relative magnitude of the costs and/or benefits associated with multiple mating (i.e., remating with different males) vary with female condition, as this may influence the strength and direction of sexual selection. Here, using the model organism Drosophila melanogaster, we test whether the indirect benefits that a nonvirgin female gains by remating (“trading-up”) are influenced by her condition (body size). We found that remating by small-bodied, low-fecundity females resulted in the production of daughters of relatively higher fecundity, whereas the opposite pattern was observed for large-bodied females. In contrast, remating had no measurable effect on the relative reproductive success of sons from dams of either body size. These results are consistent with a hypothesis based on sexually antagonistic genetic variation. The implications of these results to our understanding of the evolution and consequences of polyandry are discussed.

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