Quantitative genetic insights into the coevolutionary dynamics of male and female genitalia

The spectacular variability that typically characterizes male genital traits has largely been attributed to the role of sexual selection. Among the evolutionary mechanisms proposed to account for this diversity, two processes in particular have generated considerable interest. On the one hand, females may exploit postcopulatory mechanisms of selection to favour males with preferred genital traits (cryptic female choice; CFC), while on the other hand females may evolve structures or behaviours that mitigate the direct costs imposed by male genitalia (sexual conflict; SC). A critical but rarely explored assumption underlying both processes is that male and female reproductive traits coevolve, either via the classic Fisherian model of preference-trait coevolution (CFC) or through sexually antagonistic selection (SC). Here, we provide evidence for this prediction in the guppy (Poecilia reticulata), a polyandrous livebearing fish in which males transfer sperm internally to females via consen...通常而言，雄性生殖器官性状所典型表现出的显著变异性，在很大程度上被归因于性选择（sexual selection）的作用。在用以解释该性状多样性的诸多进化机制中，有两类过程尤其受到广泛关注。一方面，雌性可借助交配后选择机制，青睐具有被其偏好的生殖器官性状的雄性（隐秘雌性选择，cryptic female choice, CFC）；另一方面，雌性可演化出相应的结构或行为，以抵消雄性生殖器官带来的直接代价（性冲突，sexual conflict, SC）。这两类过程背后均存在一个关键却极少被探究的假设：雄性与雌性的生殖性状会发生协同演化，要么通过经典的费希尔偏好-性状协同演化模型（对应CFC），要么通过性拮抗选择（对应SC）。本研究在孔雀鱼（Poecilia reticulata，一种雌性多配偶的胎生鱼类，雄性通过体内受精向雌性传递精子，其过程经由consen……）中为这一预测提供了实证证据。