Department of Ecology, Evolution & Marine Biology, Life Sciences Building, University of Santa Barbara, Santa Barbara, CA 93106, USA.
Evolution. 2010 Sep;64(9):2767-74. doi: 10.1111/j.1558-5646.2010.00997.x.
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.
通过衡量性相互作用的直接和间接适应代价和收益，可以通过实验评估多配偶制的替代解释的可行性。当与多次交配（即与不同雄性的再交配）相关的成本和/或收益的相对大小因雌性状况而异时，这种方法会变得更加复杂，因为这可能会影响性选择的强度和方向。在这里，我们使用模式生物黑腹果蝇来测试非处女雌蝇通过再交配（“升级交易”）获得的间接收益是否受其状况（体型大小）的影响。我们发现，体型小、产卵量低的雌性进行再交配会产生相对较高产卵量的后代，而体型大的雌性则出现相反的模式。相比之下，再交配对来自任何体型大小的母代的雄性后代的相对生殖成功没有可衡量的影响。这些结果与基于性拮抗遗传变异的假设一致。讨论了这些结果对我们理解多配偶制的进化和后果的意义。
