Data from: Female mate preferences for male body size and shape promote sexual isolation in threespine sticklebacks

Female mate preferences for ecologically relevant traits may enhance natural selection, leading to rapid divergence. They may also forge a link between mate choice within species and sexual isolation between species. Here, we examine female mate preference for two ecologically important traits: body size and body shape. We measured female preferences within and between species of benthic, limnetic, and anadromous threespine sticklebacks (Gasterosteus aculeatus species complex). We found that mate preferences differed between species and between contexts (i.e., within vs. between species). Within species, anadromous females preferred males that were deep bodied for their size, benthic females preferred larger males (as measured by centroid size), and limnetic females preferred males that were more limnetic shaped. In heterospecific mating trials between benthics and limnetics, limnetic females continued to prefer males that were more limnetic like in shape when presented with benthic males. Benthic females showed no preferences for size when presented with limnetic males. These results show that females use ecologically relevant traits to select mates in all three species and that female preference has diverged between species. These results suggest that sexual selection may act in concert with natural selection on stickleback size and shape. Further, our results suggest that female preferences may track adaptation to local environments and contribute to sexual isolation between benthic and limnetic sticklebacks.

雌性对生态相关性状的择偶偏好可能强化自然选择，进而推动性状快速分化；同时，这类偏好还可能建立起物种内择偶选择与物种间生殖隔离之间的关联。本研究聚焦雌性对两类生态重要性状的择偶偏好：体型与体形。我们针对底栖、浮游及溯河洄游型三棘刺鱼（Gasterosteus aculeatus物种复合体）的种内及种间雌性偏好展开了测定。研究发现，择偶偏好存在物种间差异，同时也因情境不同（即种内与种间择偶情境）而有所区别。种内层面，溯河洄游型雌性偏好体型相对更宽厚的雄性；底栖型雌性偏好体型更大的雄性（以质心大小衡量）；浮游型雌性则偏好更具浮游型体形特征的雄性。在底栖型与浮游型的种间交配实验中，当浮游型雌性接触到底栖型雄性时，仍偏好体形更接近浮游型的雄性；而底栖型雌性在接触浮游型雄性时，未表现出对体型的选择偏好。上述结果表明，三种刺鱼的雌性均通过生态相关性状选择配偶，且雌性择偶偏好已在物种间发生分化。这意味着，在刺鱼的体型与体形相关性状上，性选择可能与自然选择协同发挥作用。此外，本研究结果还提示，雌性择偶偏好可能与物种对当地环境的适应性演化相匹配，并助力底栖型与浮游型刺鱼之间形成生殖隔离。