Data from: Evolution of a mating preference for a dual-utility trait used in intrasexual competition in genetically monogamous populations

The selection pressures by which mating preferences for ornamental traits can evolve in genetically monogamous mating systems remain understudied. Empirical evidence from several taxa supports the prevalence of dual-utility traits, defined as traits used both as armaments in intersexual selection and ornaments in intrasexual selection, as well as the importance of intrasexual resource competition for the evolution of female ornamentation. Here, we study whether mating preferences for traits used in intrasexual resource competition can evolve under genetic monogamy. We find that a mating preference for a competitive trait can evolve and affect the evolution of the trait. The preference is more likely to persist when the fecundity benefit for mates of successful competitors is large and the aversion to unornamented potential mates is strong. The preference can persist for long periods or potentially permanently even when it incurs slight costs. Our results suggest that, when females use ornaments as signals in intrasexual resource competition, males can evolve mating preferences for those ornaments, illuminating both the evolution of female ornamentation and the evolution of male preferences for female ornaments in monogamous species.

遗传单配制交配系统（genetically monogamous mating systems）中，驱动装饰性性状（ornamental traits）交配偏好演化的选择压力（selection pressures）迄今仍未得到充分研究。已有针对多个类群的实证研究证据显示，双功能性状（dual-utility traits，即同时在性间选择（intersexual selection）中充当武器、在性内选择（intrasexual selection）中作为装饰的性状）的分布较为普遍；同时，性内资源竞争（intrasexual resource competition）对于雌性装饰性状（female ornamentation）的演化具有重要意义。本研究聚焦于遗传单配制条件下，用于性内资源竞争的性状的交配偏好能否发生演化。研究结果表明，对竞争性性状的交配偏好确实可以演化，并对该性状的演化进程产生影响。当成功竞争者的配偶所获得的繁殖收益（fecundity benefit）较高、个体对无装饰性状潜在配偶（unornamented potential mates）的厌恶程度较强时，该交配偏好更易持续存续。即便该偏好会带来轻微成本，其仍可长期存在，甚至实现永久存续。本研究结果提示，当雌性将装饰性状作为性内资源竞争的信号时，雄性可演化出针对这些装饰性状的交配偏好，这为单配制物种中雌性装饰性状的演化，以及雄性对雌性装饰性状的偏好演化提供了全新的理论阐释。