Sexual conflict over remating interval is modulated by the sex peptide pathway

Sexual conflict, in which the evolutionary interests of males and females diverge, shapes the evolution of reproductive systems across diverse taxa. Here, we used the fruit fly to study sexual conflict in natural, three-way interactions comprising a female, her current and previous mates. We manipulated the potential for sexual conflict by using sex peptide receptor (SPR) null females and by varying remating from 3 to 48 h, a period during which natural rematings frequently occur. SPR-lacking females do not respond to sex peptide (SP) transferred during mating and maintain virgin levels of high receptivity and low fecundity. In the absence of SPR, there was a convergence of fitness interests, with all individuals gaining highest productivity at 5 h remating. This suggests that the expression of sexual conflict was reduced. We observed an unexpected second male-specific advantage to early remating, resulting from an increase in the efficiency of second male sperm use. This early window o...

性冲突（Sexual conflict）指雌雄双方的进化利益产生分歧，其塑造了各类生物类群生殖系统的演化历程。本研究以果蝇为模式生物，探究自然状态下包含1只雌性、其当前配偶与前任配偶的三方互作体系中的性冲突。我们通过使用性肽受体（sex peptide receptor, SPR）敲除雌性，并将再交配间隔设置为3至48小时（该时段内自然状态下的再交配事件频发），操控性冲突发生的潜在可能性。缺乏SPR的雌性无法对交配过程中传递的性肽（sex peptide, SP）产生响应，并维持处女个体的高交配接受性与低繁殖力水平。在缺失SPR的条件下，雌雄双方的适合度利益趋于一致，所有个体在再交配间隔为5小时时均可获得最高的生殖产量，这表明性冲突的表达被削弱。我们还观察到一个意外的雄性特异性优势：早期再交配可通过提升第二雄精子的利用效率，赋予雄性此项优势。这一早期窗口……