Data from: Grab my tail: evolution of dazzle stripes and colourful tails in lizards

Understanding the functions of animal coloration has been a long-standing question in evolutionary biology. For example, the widespread occurrence of striking longitudinal stripes and colourful tails in lizards begs for an explanation. Experiments have suggested that colourful tails can deflect attacks towards the tail (the ‘deflection’ hypothesis), which is sacrificable in most lizards, thereby increasing the chance of escape. Studies also suggest that in moving lizards, longitudinal body stripes can redirect predators’ strikes towards the tail through the ‘motion dazzle’ effect. Despite these experimental studies, the ecological factors associated with the evolution of such striking colourations remain unexplored. Here, we investigated if predictions from motion dazzle and attack deflection could explain the widespread occurrence of these striking marks using comparative methods and information on eco-physiological variables (caudal autotomy, diel activity, microhabitat, and body temperature) potentially linked to their functioning. We found both longitudinal stripes and colourful tails are associated with diurnal activity and with the ability to lose the tail. Compared to stripeless species, striped species are more likely to be ground-dwelling and have higher body temperature, emphasizing the connection of stripes to mobility and rapid escape strategy. Colourful tails and stripes have evolved multiple times in a correlated fashion, suggesting that their functions may be linked. Overall, our results together with previous experimental studies support the notion that stripes and colourful tails in lizards may have protective functions based on deflective and motion dazzle effects.

探究动物体色的功能，是进化生物学领域一个长久以来的研究议题。例如，蜥蜴类动物中广泛存在的醒目纵纹与色彩艳丽的尾部，便亟需得到合理的阐释。已有实验研究表明，色彩艳丽的尾部可将捕食者的攻击引导至尾部（偏转假说（deflection hypothesis））——多数蜥蜴的尾部具备可牺牲性，因此这一策略能够提升个体逃脱概率。另有研究指出，处于移动状态的蜥蜴，其体表纵纹可通过运动炫目效应（motion dazzle effect）将捕食者的攻击导向尾部。尽管已有上述实验研究，但这类醒目体色演化背后的关联生态因子仍未得到系统探究。
本研究采用比较分析方法，并结合可能与体色功能相关的生态生理变量数据——包括断尾自割（caudal autotomy）、昼夜活动节律（diel activity）、微生境（microhabitat）与体温——探究运动炫目效应与攻击偏转假说的相关预测，能否解释蜥蜴类醒目体色标记的广泛分布现象。研究结果显示，纵纹与色彩尾部均与昼行性活动及断尾能力存在显著关联。相较于无纹物种，具纵纹的蜥蜴更倾向于陆栖生活且体温更高，这进一步凸显了纵纹与运动能力及快速逃生策略之间的关联。色彩尾部与纵纹在演化过程中多次协同出现，提示二者的功能可能存在关联。
综上，本研究结果与既往实验研究共同支持这一观点：蜥蜴的纵纹与色彩尾部，可基于攻击偏转与运动炫目效应发挥保护性功能。