Data from: The effects of male harm vary with female quality and environmental complexity in Drosophila melanogaster

Mate competition provides the opportunity for sexual selection which often acts strongly on males, but also the opportunity for sexual conflict that can alter natural selection on females. Recent attention has focused on the potential of sexual conflict to weaken selection on females if male sexual attention, and hence harm, is disproportionately directed toward high over low quality females, thereby reducing the fitness difference between these females. However, sexual conflict could instead strengthen selection on females if low quality females are more sensitive to male harm than high quality females, thereby magnifying fitness differences between them. We quantify the effects of male exposure on low vs. high quality females in Drosophila melanogaster in each of two environments (“simple” and “complex”) that are known to alter behavioural interactions. We show that the effects of male harm are greater for low compared to high quality females in the complex but not the simple environment, consistent with mate competition strengthening selection on females in the former but not in the latter environment.

交配竞争（mate competition）不仅为性选择（sexual selection）提供了契机——性选择往往对雄性施加强烈的选择压力，同时也会催生性冲突（sexual conflict），而性冲突能够改变针对雌性的自然选择（natural selection）进程。过往研究多聚焦于一种潜在情形：若雄性的性关注及其附带的伤害，不成比例地偏向高质量雌性而非低质量雌性，便会削弱针对雌性的选择压力，进而缩小两类雌性间的适合度（fitness）差异。然而，若低质量雌性相较于高质量雌性对雄性造成的伤害更为敏感，则性冲突反而会强化针对雌性的选择压力，进一步扩大二者间的适合度差异。本研究以黑腹果蝇（Drosophila melanogaster）为研究对象，在两类已被证实会改变行为互动模式的环境——“简单环境”与“复杂环境”中，分别量化了雄性暴露对低质量与高质量雌性的影响。研究结果表明，在复杂环境中，雄性造成的伤害对低质量雌性的影响显著高于高质量雌性，而在简单环境中则无此现象；这一结果与“交配竞争会在复杂环境中强化针对雌性的选择压力，而在简单环境中则无此效应”的推论相符。