Data from: Poison frog color morphs express assortative mate preferences in allopatry but not sympatry

The concurrent divergence of mating traits and preferences is necessary for the evolution of reproductive isolation via sexual selection, and such coevolution has been demonstrated in diverse lineages. However, the extent to which assortative mate preferences are sufficient to drive reproductive isolation in nature is less clear. Natural contact zones between lineages divergent in traits and preferences provide exceptional opportunities for testing the predicted evolutionary consequences of such divergence. The strawberry poison frog (Oophaga pumilio) displays extreme color polymorphism in and around the young Bocas del Toro archipelago. In a transition zone between red and blue allopatric lineages, we asked whether female preferences diverged along with coloration, and whether any divergent preferences persist in a zone of sympatry. When choosing among red, blue and phenotypically intermediate males, females from monomorphic red and monomorphic blue populations both expressed assortative preferences. However, red, blue, and intermediate females from the contact zone all preferred red males, suggesting that divergent preferences may be insufficient to effect behavioral isolation. Our results highlight the complexity of behavioral isolation, and the need for studies that can reveal the circumstances under which divergent preferences do and do not contribute to speciation.

通过性选择演化出生殖隔离，需要交配性状与配偶偏好的协同分化；这类协同演化已在多个类群中得到证实。然而，自然界中选型交配偏好（assortative mate preferences）是否足以驱动生殖隔离，目前仍尚无明确结论。性状与偏好存在分化的类群之间形成的自然接触带，为检验此类分化所预测的演化后果提供了绝佳研究契机。草莓箭毒蛙（Oophaga pumilio）在年轻的博卡斯德尔托罗群岛及其周边区域展现出极强的体色多态性。在红色与蓝色异域类群之间的过渡带中，本研究旨在探究两个问题：其一，雌性配偶偏好是否会随体色发生分化；其二，此类分化后的偏好是否会在同域分布（sympatry）的接触带中得以保留。当在红色、蓝色以及表型中间型的雄性个体间进行选择时，来自单态红色种群与单态蓝色种群的雌性均表现出选型交配偏好。然而，接触带内的红色、蓝色以及中间型雌性个体均偏好红色雄性，这表明分化的配偶偏好可能不足以促成行为隔离（behavioral isolation）。本研究结果凸显了行为隔离的复杂性，同时也提示，需要开展更多研究以明确分化的配偶偏好在何种情境下会或不会参与物种形成过程。