Data from: Beauty in the eyes of the beholders: color vision is tuned to mate preference in the Trinidadian guppy (Poecilia reticulata)

A broad range of animals use visual signals to assess potential mates, and the theory of sensory exploitation suggests variation in visual systems drives mate preference variation due to sensory bias. Trinidadian guppies (Poecilia reticulata), a classic system for studies of the evolution of female mate choice, provide a unique opportunity to test this theory by looking for co-variation in visual tuning, light environment, and mate preferences. Female preference co-evolves with male coloration, such that guppy females from ‘low predation’ environments have stronger preferences for males with more orange/red coloration than do females from ‘high predation’ environments. Here we show that color vision also varies across populations, with ‘low’ predation guppies investing more of their color vision to detect red/orange coloration. In independently colonized watersheds, guppies expressed higher levels of both LWS-1 and LWS-3 (the most abundant LWS opsins) in ‘low predation’ populations than ‘high predation’ populations at a time that corresponds to differences in cone cell abundance. We also observed that the frequency of a coding polymorphism differed between high and low predation populations. Together this shows that the variation underlying preference could be explained by simple changes in expression and coding of opsins, providing important candidate genes to investigate the genetic basis of variation in this model system.

诸多动物均会借助视觉信号评估潜在配偶，感官利用理论（sensory exploitation）指出，视觉系统的变异会通过感官偏好效应驱动配偶偏好的变异。特立尼达孔雀鱼（Poecilia reticulata）作为研究雌性配偶选择演化的经典模型系统，为验证该理论提供了绝佳契机——可通过探究视觉调谐、光照环境与配偶偏好之间的共变异关系开展相关检验。雌性配偶偏好与雄性体色存在协同演化现象：相较于来自“高捕食压力”环境的雌性孔雀鱼，来自“低捕食压力”环境的雌性对橙红色体色更为发达的雄性展现出更强的偏好。本研究发现，不同种群的孔雀鱼色觉亦存在差异：“低捕食压力”种群的孔雀鱼会在色觉感知上投入更多资源以识别红/橙色调。在独立定植的流域中，“低捕食压力”种群的孔雀鱼的LWS-1与LWS-3（丰度最高的LWS视蛋白）的表达水平均高于“高捕食压力”种群，这一差异与视锥细胞丰度的差异相吻合。本研究同时观察到，高、低捕食压力种群间的编码多态性频率存在显著差异。综上，配偶偏好背后的变异可通过视蛋白表达与编码的简单改变得以解释，这为探究该模型系统中偏好变异的遗传基础提供了重要的候选基因。