Data from: Non-uniform evolutionary response of gecko eye size to changes in diel activity patterns

Geckos feature a large range of eye sizes, but what drives this phenotypic diversity is currently unknown. Earlier studies point towards diel activity patterns (DAP) and locomotory mode, but phylogenetic comparative studies in support of the proposed adaptive mode of eye evolution are lacking. Here we test the hypothesis of DAP as the driver of eye size evolution with a dataset on 99 species of gecko. Results from phylogenetic generalized least square analysis (PGLS) and multivariate model-fitting reveal smaller eyes in diurnal geckos consistent with different phenotypic optima. However, Bayesian analyses of selective regime shifts demonstrate that only 2 of 9 transitions from nocturnal to diurnal activity are coupled with decreases in eye size, and 2 other regime shifts are not associated with DAP transitions. This non-uniform evolutionary response suggests that eye size is not the only functionally relevant variable. Evolutionary adaptations may therefore include different combinations of several traits (e.g., photoreceptors), all with the same functional outcome. Our results further demonstrate that DAP only partially explains eye size diversity in geckos. As open habitats favor the evolution of large eyes while obstructed habitats favor small eyes, the degree of habitat clutter emerges as another potential axis of eye diversification.

壁虎类物种的眼尺寸存在广泛的变异范围，但其表型多样性的驱动机制目前仍不明晰。既往研究曾指向昼夜活动模式（Diel Activity Patterns, DAP）与运动模式，但目前仍缺乏支持所提出的眼睛演化适应性模式的系统发育比较研究。本研究基于涵盖99种壁虎的数据集，验证了昼夜活动模式是驱动眼尺寸演化的核心因素这一假说。系统发育广义最小二乘分析（Phylogenetic Generalized Least Square Analysis, PGLS）与多变量模型拟合的结果显示：昼行性壁虎的眼尺寸更小，这一结果符合不同表型最适值的预期。然而，针对选择模式转变的贝叶斯分析结果显示：9次从夜行性到昼行性的活动模式转变中，仅有2次伴随眼尺寸的减小，另有2次模式转变并未与昼夜活动模式的改变相关联。这种非均一的演化响应表明，眼尺寸并非唯一具有功能相关性的性状变量。因此，演化适应性可能包含多种性状（如光感受器）的不同组合，且这些组合均可达成相同的功能结果。本研究结果进一步表明，昼夜活动模式仅能部分解释壁虎类的眼尺寸多样性。由于开阔生境利于大眼的演化，而遮蔽生境则利于小眼的演化，因此生境杂乱程度成为了驱动眼尺寸多样化的另一潜在维度。