Data from: Developmental effects of visual environment on species-assortative mating preferences in Lake Victoria cichlid fish

Local adaptation can be a potent force in speciation, with environmental heterogeneity leading to niche specialization and population divergence. However, local adaption often requires non-random mating in order to generate reproductive isolation. Population divergence in sensory properties can be particularly consequential in speciation, affecting both ecological adaptation and sexual communication. Pundamilia pundamila and Pundamilia nyererei are two closely related African cichlid species that differ in male coloration, blue vs. red. They co-occur at rocky islands in southern Lake Victoria, but inhabit different depth ranges with different light environments. The species differ in colour vision properties and females exert species-specific preferences for blue vs. red males. Here, we investigated the mechanistic link between colour vision and preference, which could provide a rapid route to reproductive isolation. We tested the behavioural components of this link by experimentally manipulating colour perception – we raised both species and their hybrids under light conditions mimicking shallow and deep habitats - and tested female preference for blue and red males under both conditions. We found that rearing light significantly affected female preference: shallow-reared females responded more strongly to P. pundamilia males and deep-reared females favored P. nyererei males - implying that visual development causally affects mate choice. These results are consistent with sensory-drive predictions, suggesting that the visual environment is key to behavioural isolation of these species. However, the observed plasticity could also make the species barrier vulnerable to environmental change: species-assortative preferences were weaker in females that were reared in the other species’ light condition.

局部适应（local adaptation）是物种形成过程中的强效驱动力，环境异质性可推动生态位特化与种群分化。然而，局部适应通常需要非随机交配才能建立生殖隔离（reproductive isolation）。感官性状的种群分化在物种形成中尤为关键，可同时影响生态适应与性信号交流。彼得丽鲷（Pundamilia pundamila）与尼氏彼得丽鲷（Pundamilia nyererei）是两种亲缘关系密切的非洲慈鲷，雄性体色分别为蓝色与红色，二者性状差异显著。二者共同栖息于维多利亚湖南部的岩质岛礁生境，但各自占据不同的水深区间，所处光照环境亦存在明显差异。这两个物种的色觉性状存在差异，雌性个体对蓝色、红色雄性分别表现出物种特异性的择偶偏好。本研究围绕色觉与择偶偏好间的机制关联展开探究，该关联或可成为生殖隔离快速形成的潜在路径。我们通过实验操控色觉感知来验证该关联的行为学组分：将两个物种及其杂交后代饲养于模拟浅、深生境的光照条件下，并分别在两种光照环境中测试雌性对蓝色、红色雄性的择偶偏好。研究结果显示，饲养光照环境对雌性择偶偏好具有显著调控作用：浅水环境光照下饲养的雌性对彼得丽鲷雄性的响应更强，而深水环境光照下饲养的雌性则更偏好尼氏彼得丽鲷雄性——这表明视觉发育对配偶选择存在因果性影响。该结果与感官驱动（sensory drive）理论的预测相符，表明视觉环境是这两个物种实现行为隔离的核心驱动因素。但本次观测到的表型可塑性也可能使物种间的生殖隔离屏障易受环境变化干扰：当雌性在另一物种的光照环境中饲养时，其物种匹配性择偶偏好会显著减弱。