Female control over multiple matings increases the opportunity for postcopulatory sexual selection

It is widely acknowledged that in most species sexual selection continues after mating. Although it is generally accepted that females play an important role in generating paternity biases (i.e., cryptic female choice), we lack a quantitative understanding of the relative importance of female-controlled processes in influencing variance in male reproductive fitness. Here we address this question experimentally using the guppy Poecilia reticulata, a polyandrous fish in which pre- and postcopulatory sexual selection jointly determine male reproductive fitness. We used a paired design to quantify patterns of paternity for pairs of rival males across two mating contexts, one in which the female retained full control over double (natural) matings and one where sperm from the same two males were artificially inseminated into the female. We then compared the relative paternity share for a given pair of males across both contexts, enabling us to test the key prediction that patterns of paternit...学界普遍认为，多数物种的交配后仍存在性选择（sexual selection）。尽管学界普遍认可雌性在产生父权偏倚（即隐蔽雌性选择（cryptic female choice)）中发挥重要作用，但我们仍缺乏对雌性调控过程影响雄性繁殖适合度（male reproductive fitness）变异的相对重要性的定量认知。本研究以孔雀鱼（Poecilia reticulata）为实验对象——这是一种实行一妻多夫制的鱼类，其雄性繁殖适合度由交配前和交配后性选择共同决定——来实验性地解答这一问题。本研究采用配对设计（paired design），在两种交配情境下量化成对竞争雄性的父权分布模式：一种情境中雌性对两次自然交配保有完全控制权，另一种情境则将同一对雄性的精子人工授精至雌性体内。随后我们比较了给定雄性对在两种情境下的相对父权份额，借此得以检验核心预测：父权分布模式……