Data from: Divergence in sex peptide-mediated female post-mating responses in Drosophila melanogaster

Transfer and receipt of seminal fluid proteins crucially affect reproductive processes in animals. Evolution in these male ejaculatory proteins is explained with post-mating sexual selection, but we lack a good understanding of the evolution of female post-mating responses to these proteins. Some of these proteins are expected to mediate sexually antagonistic coevolution generating the expectation that females evolve resistance. One candidate in Drosophila melanogaster is the sex peptide (SP) which confers cost of mating in females. Here, we compared female SP-induced post-mating responses across three D. melanogaster wild type populations after mating with SP-lacking versus control males including fitness measures. Surprisingly, we did not find any evidence for SP-mediated fitness costs in any of the populations. However, female lifetime reproductive success and lifespan were differently affected by SP receipt indicating that female post-mating responses diverged among populations. Injection of synthetic SP into virgin females further supports these findings and suggests that females from different populations require different amounts of SP to effectively initiate post-mating responses. Molecular analyses of the sex peptide receptor suggest that genetic differences might explain the observed phenotypical divergence. We discuss the evolutionary processes that might have caused this divergence in female post-mating responses.

精浆蛋白（seminal fluid proteins）的传递与接收对动物的生殖过程至关重要。这类雄性射精蛋白的演化可通过交配后性选择来解释，但我们对雌性针对这些蛋白的交配后响应的演化机制仍缺乏充分认知。其中部分蛋白被认为介导了性拮抗协同进化，由此推测雌性会演化出相应的抗性。在黑腹果蝇（Drosophila melanogaster）中，性肽（sex peptide, SP）是候选靶点之一，该蛋白会对雌性造成交配代价。本研究中，我们对比了三个黑腹果蝇野生型种群的雌性在与缺失性肽的雄性或对照雄性交配后的性肽诱导交配后响应，并纳入了适合度测定指标。令人意外的是，我们未在任何种群中发现性肽介导交配代价的证据。不过，雌性的终生繁殖成功率与寿命受性肽接收的影响存在种群间差异，表明不同种群的雌性交配后响应已出现分化。向处女雌蝇注射合成性肽的实验进一步佐证了上述发现，且提示不同种群的雌性需要不同剂量的性肽才能有效触发交配后响应。对性肽受体（sex peptide receptor）的分子分析表明，遗传差异或许可以解释观测到的表型分化。我们最后讨论了可能导致雌性交配后响应出现分化的演化过程。