Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut.
Department of Ecology and Evolutionary Biology, University of California Santa Cruz, Santa Cruz, California.
J Evol Biol. 2019 Jun;32(6):545-558. doi: 10.1111/jeb.13436. Epub 2019 Apr 2.
Sexual conflict over the indirect benefits of mate choice may arise when traits in one sex limit the ability of the other sex to freely choose mates but when these coercive traits are not necessarily directly harmful (i.e. forced fertilization per se). Although we might hypothesize that females can evolve resistance in order to retain the indirect, genetic benefits (reflected in offspring attractiveness) of mating with attractive males, up to now it has been difficult to evaluate potential underlying mechanisms. Traditional theoretical approaches do not usually conceptually distinguish between female preference for male mating display and female resistance to forced fertilization, yet sexual conflict over indirect benefits implies the simultaneous action of all of these traits. Here, we present an integrative theoretical framework that draws together concepts from both sexual selection and sexual conflict traditions, allowing for the simultaneous coevolution of displays and preferences, and of coercion and resistance. We demonstrate that it is possible for resistance to coercion to evolve in the absence of direct costs of mating to preserve the indirect benefits of mate choice. We find that resistance traits that improve the efficacy of female mating preference can evolve as long as females are able to attain some indirect benefits of mating with attractive males, even when both attractive and unattractive males can coerce. These results reveal new evolutionary outcomes that were not predicted by prior theories of indirect benefits or sexual conflict.
性选择冲突可能会在一方的特征限制另一方自由选择配偶的能力，但这些强制性特征不一定直接有害（即强制性受精本身）时出现。尽管我们可以假设雌性可以进化出抵抗力，以保留与有吸引力的雄性交配的间接遗传利益（反映在后代的吸引力上），但到目前为止，评估潜在的潜在机制一直很困难。传统的理论方法通常不会在概念上区分雌性对雄性交配展示的偏好和雌性对强制受精的抵抗力，但间接利益的性冲突意味着所有这些特征同时起作用。在这里，我们提出了一个综合理论框架，该框架结合了性选择和性冲突传统的概念，允许展示和偏好、强制和抵抗力的同时共同进化。我们证明，即使有吸引力和没有吸引力的雄性都可以强制受精，为了保留配偶选择的间接利益，也有可能在不产生交配直接成本的情况下进化出对强制的抵抗力。我们发现，只要雌性能够获得与有吸引力的雄性交配的一些间接利益，即使有吸引力和没有吸引力的雄性都可以强制受精，提高雌性交配偏好效力的抵抗特征也可以进化。这些结果揭示了先前关于间接利益或性冲突的理论所没有预测到的新的进化结果。
