The ecological stage changes benefits of mate choice and drives preference divergence

Preference divergence is thought to contribute to reproductive isolation. Ecology can alter the way selection acts on female preferences, making them most likely to diverge when ecological conditions vary among populations. We present a novel mechanism for ecologically dependent sexual selection, termed ‘the ecological stage’ to highlight its ecological dependence. Our hypothesized mechanism emphasizes that males and females interact over mating in a specific ecological context, and different ecological conditions change the costs and benefits of mating interactions, selecting for different preferences in distinct environments and different male traits, especially when traits are condition dependent. We test key predictions of this mechanism in a sympatric threespine stickleback species pair. We used a maternal half-sib split-clutch design for both species, mating females to attractive and unattractive males, and raising progeny on alternate diets that mimic the specialized diets of the...

择偶偏好分化被认为可促进生殖隔离。生态条件能够改变选择作用于雌性择偶偏好的方式，使得当不同种群间的生态环境存在差异时，这类偏好最易发生分化。我们提出了一种依赖于生态环境的性选择新机制，将其命名为“生态场景（the ecological stage）”，以凸显其生态依赖性。我们提出的这一假说机制强调，雄性与雌性会在特定的生态背景下进行交配互动，而不同的生态条件会改变交配互动的成本与收益，进而在不同环境中筛选出不同的择偶偏好与雄性性状，尤其当这些性状依赖于个体状态时。我们在一对同域分布的三刺棘鱼（threespine stickleback）物种中检验了该机制的关键预测。我们为两个物种均采用了母系半同胞分卵设计，让雌性分别与具有吸引力和无吸引力的雄性交配，并将后代置于两种替代食谱中饲养，该食谱模拟了该物种特化的饮食……