Female discrimination thresholds frequently exceed local male display variation: implications for mate choice dynamics and sexual selection

Among the factors that can influence female mate choice decisions is the degree to which females differentiate among similar displays: as differences decrease, females are expected to eventually stop discriminating. This discrimination threshold, in conjunction with the magnitude of male trait variation females regularly encounter while making mate choice decisions, may have important consequences for sexual selection. If local display variation is above the discrimination threshold, female preferences should translate into higher mating success for the more attractive male. But if display variation is frequently below the threshold, the resulting increased pattern of random mating may obscure the existence of female mate choice. I investigated the interplay between female discrimination and male display variation in green treefrogs (Hyla cinerea), and found that call trait differences between nearest neighbour males were frequently smaller than what females are expected to discriminate...

影响雌性配偶选择决策的因素之一，是雌性对相似求偶展示的区分程度：当展示间的差异缩小时，雌性最终会停止进行择偶区分。这一区分阈值，与雌性在择偶过程中常接触的雄性性状变异幅度相结合，可能对性选择产生重要影响。若本地求偶展示的变异程度高于该区分阈值，雌性的择偶偏好将转化为更具吸引力雄性的更高交配成功率；但若展示间的变异程度频繁低于该阈值，由此产生的随机交配比例升高的模式，可能会掩盖雌性配偶选择的存在。本研究以绿树蛙（Hyla cinerea）为对象，探究了雌性区分行为与雄性求偶展示变异之间的相互作用，结果发现邻近雄性个体间的鸣唱性状差异，往往小于雌性理论上能够区分的阈值范围……