Do male fish prefer them big and colourful? Non-random male courtship effort in a viviparous fish with negligible paternal investment

In the majority of sexual species, there are asymmetries in reproductive effort, with males typically investing more in securing matings and females investing more in producing offspring. This causes males to mate less discriminately than females. Yet males may also become choosy if the following conditions are met: (a) that females vary in their reproductive value, (b) that males can perceive this variation, and (c) that mating with one female reduces the possibility of mating with another. These conditions may be met in the livebearing Goodeidae, a clade of Mexican fish whose females are often brightly coloured and whose males display costly ornaments and courtship as the only means to obtain matings. Males of the black-finned goodeid (Girardinichthys viviparus) have relatively simple, yet costly courtship behaviour, with mating probability depending on the duration of one-to-one courtship episodes, thus by courting one female they must ignore others. We evaluated whether the decision...

在绝大多数有性生殖物种中，繁殖投入存在不对称现象：雄性通常更侧重于投入资源以获取交配机会，而雌性则更多将资源投入后代生产。这使得雄性的交配选择相较于雌性更为宽松。然而当满足以下三项条件时，雄性也可能演化出选择偏好：(a) 雌性个体的繁殖价值存在差异；(b) 雄性能够感知到这种差异；(c) 与某一雌性交配会降低与其他雌性交配的可能性。这类条件在胎生鳉科（Goodeidae）鱼类中可被满足：该类群为墨西哥特有的淡水鱼类演化支，其雌性个体通常体色艳丽，雄性则需通过代价高昂的装饰结构展示与求偶行为，作为获取交配机会的唯一手段。黑鳍胎生鳉（Girardinichthys viviparus）的雄性拥有相对简洁但代价高昂的求偶行为，其交配概率取决于一对一求偶互动的时长，因此雄性在向某一雌性求偶时，必然会忽略其他雌性。我们评估了其交配决策是否……