Data from: Diurnal lighting patterns and habitat alter opsin expression and colour preferences in a killifish

Spatial variation in lighting environments frequently leads to population variation in colour patterns, colour preferences and visual systems. Yet lighting conditions also vary diurnally, and many aspects of visual systems and behaviour vary over this time scale. Here, we use the bluefin killifish (Lucania goodei) to compare how diurnal variation and habitat variation (clear versus tannin-stained water) affect opsin expression and the preference to peck at different-coloured objects. Opsin expression was generally lowest at midnight and dawn, and highest at midday and dusk, and this diurnal variation was many times greater than variation between habitats. Pecking preference was affected by both diurnal and habitat variation but did not correlate with opsin expression. Rather, pecking preference matched lighting conditions, with higher preferences for blue at noon and for red at dawn/dusk, when these wavelengths are comparatively scarce. Similarly, blue pecking preference was higher in tannin-stained water where blue wavelengths are reduced. In conclusion, L. goodei exhibits strong diurnal cycles of opsin expression, but these are not tightly correlated with light intensity or colour. Temporally variable pecking preferences probably result from lighting environment rather than from opsin production. These results may have implications for the colour pattern diversity observed in these fish.光照环境的空间异质性常会引发种群间色彩模式、色彩偏好与视觉系统的差异。然而光照条件同样存在昼夜波动，而视觉系统与行为的诸多特征也会随这一时间尺度发生变化。本研究以蓝鳍灯鳉（bluefin killifish, Lucania goodei）为实验对象，对比昼夜变化与栖息地差异（清水 vs 单宁染色水体）对视蛋白（opsin）表达以及对不同色彩物体啄食偏好的影响。视蛋白表达量通常在午夜与黎明时最低，正午与黄昏时最高，且这种昼夜差异的幅度远高于栖息地间的差异。啄食偏好同时受昼夜变化与栖息地差异的影响，但与视蛋白表达量并无显著关联。相反，啄食偏好与光照条件高度匹配：正午时对蓝色的偏好更强，而在黎明/黄昏时对红色的偏好更为显著——此时这两类波长的光照相对稀缺。类似地，在蓝光波长被削弱的单宁染色水体中，蓝色彩啄食偏好也更为突出。综上，L. goodei的视蛋白表达存在显著的昼夜周期，但这些周期与光照强度或色彩并无紧密相关性。随时间动态变化的啄食偏好更可能由光照环境而非视蛋白合成所导致。本研究结果或可为这类鱼类所展现的色彩模式多样性提供相关启示。