Data from: Differences in male coloration are predicted by divergent sexual selection between populations of a cichlid fish

Female mating preferences can influence both intraspecific sexual selection and interspecific reproductive isolation, and have therefore been proposed to play a central role in speciation. Here, we investigate experimentally in the African cichlid fish Pundamilia nyererei if differences in male coloration between three para-allopatric populations (i.e. island populations with gene flow) of P. nyererei are predicted by differences in sexual selection by female mate choice between populations. Second, we investigate if female mating preferences are based on the same components of male coloration and go in the same direction when females choose among males of their own population, their own and other conspecific populations and a closely related para-allopatric sister-species, P. igneopinnis. Mate-choice experiments revealed that females of the three populations mated species-assortatively, that populations varied in their extent of population-assortative mating and that females chose among males of their own population based on different male colours. Females of different populations exerted directional intrapopulation sexual selection on different male colours, and these differences corresponded in two of the populations to the observed differences in male coloration between the populations. Our results suggest that differences in male coloration between populations of P. nyererei can be explained by divergent sexual selection and that population-assortative mating may directly result from intrapopulation sexual selection.

雌性择偶偏好既能影响种内性选择，也能影响种间生殖隔离，因此被认为在物种形成过程中发挥核心作用。本研究以非洲慈鲷尼雷尔朴丽鱼（Pundamilia nyererei）为实验对象，首先探究该物种三个准异域种群（即存在基因交流的岛屿种群）间的雄性体色差异，是否可通过种群间雌性择偶产生的性选择差异进行预测。其次，本研究还探讨了当雌性在本种群雄性、本种群与其他同种种群雄性，以及近缘准异域姊妹物种火鳍朴丽鱼（P. igneopinnis）雄性中进行选择时，其择偶偏好是否基于相同的雄性体色组分，且选择方向是否一致。择偶实验结果显示，三个种群的雌性均表现出物种选型交配行为，不同种群的种群选型交配程度存在差异，且雌性针对本种群雄性的择偶选择依据不同的雄性体色特征。不同种群的雌性会对不同的雄性体色特征施加定向的种群内性选择，其中两个种群的这类差异与种群间已观测到的雄性体色差异相契合。本研究结果表明，尼雷尔朴丽鱼种群间的雄性体色差异可通过歧化性选择得到解释，而种群选型交配可能直接由种群内的性选择所产生。