Sexual selection maintains a female-specific character in a species with dynamic sex roles

The effects of sexual selection are more conspicuous among male animals, and as a result the majority of sexual selection research focuses on males. However, burgeoning evidence suggests that sexual selection also acts on females, and there have been calls for an increased focus on females. Here, we used a multivariate approach to analyze sexual selection in Kawanaphila nartee, a spermatophore gift-giving bushcricket with dynamic sex roles. Early in the breeding season females compete for males, and later, when environmental food resources are more abundant, sex roles revert to Darwinian convention. Ear size, which is much greater in females than in males, has been suggested to affect female fitness, as females with larger ears are more likely to reach calling males first under sex role reversed conditions. We tested this suggestion and found evidence of positive linear and nonlinear correlational selection acting on female ear size early in the breeding season (under reversed sex roles...

性选择（sexual selection）的效应在雄性动物中更为显著，因此绝大多数性选择研究均以雄性为核心对象。然而，日益增多的证据表明，性选择同样对雌性发挥作用，学界也已呼吁强化对雌性性选择的研究关注度。本研究采用多变量分析方法，对Kawanaphila nartee——一种具有动态性角色的精荚馈赠型灌丛蟋蟀——的性选择展开分析。在繁殖季早期，雌性会竞争雄性配偶；而当环境食物资源更为充裕的繁殖后期，性角色则会回归达尔文提出的经典模式。此前已有研究指出，雌性耳部尺寸（雌性耳部远大于雄性）会影响雌性适合度，因为在性角色反转的条件下，耳部更大的雌性更有可能率先抵达鸣唱的雄虫处。本研究对这一假说进行了验证，并发现了在繁殖季早期（性角色反转条件下……），雌性耳部尺寸受到正向线性选择与非线性相关选择作用的相关证据。