Data from: Body size and evolution of motion dazzle coloration in lizards

‘Motion dazzle’ patterns are a form of defensive coloration suggested to prevent successful capture during motion by causing predators to misjudge the direction or speed of prey movement. Several studies have found results supporting this idea, but little is known about the factors that favour the evolution of these antipredator colorations. A recent experimental study has suggested that the longitudinal striped patterns on body of lizards can redirect attacks to the tail via the motion dazzle effect. Using a virtual predation experiment with humans and a phylogenetic comparative analysis, we show that evolution of longitudinal striped coloration is associated with prey size. Experiments showed that longitudinal stripes located at the anterior reduced lethal attacks (i.e. attacks directed to the anterior and centre), but this benefit was greater for shorter prey. Our comparative analysis revealed a negative association between stripe occurrence and body length, but no association between stripes and body width. Overall, our results suggest that the dazzle effect produced by stripes is more advantageous in shorter lizards than in longer ones, and that the error induced by stripes might be distributed along the axis parallel to the prey trajectory. We discuss reasons why dazzle coloration could be associated with evolution of smaller body size in animals.

“运动炫目（Motion dazzle）”模式是一类防御体色策略，其作用机制被认为是通过让捕食者误判猎物的运动方向或速度，从而阻止捕食者成功捕获移动中的猎物。已有多项研究为这一假说提供了支持证据，但目前学界对推动这类反捕食体色演化的影响因素仍知之甚少。近期一项实验研究表明，蜥蜴体表的纵向条纹可通过运动炫目效应，将攻击目标引导至尾部。本研究借助人类参与的虚拟捕食实验与系统发育比较分析，证实纵向条纹体色的演化与猎物体型存在关联。实验结果显示，位于躯体前部的纵向条纹可减少致命攻击（即针对躯体前部与中部的攻击），但这类收益在体型更小的猎物身上更为显著。我们的比较分析还发现，条纹出现概率与躯体长度呈负相关，但条纹分布与躯体宽度并无关联。综合来看，本研究结果表明，条纹所产生的炫目效应在体型更小的蜥蜴身上比体型更大的蜥蜴更具优势，且条纹引发的感知误差可能沿与猎物运动轨迹平行的轴分布。本文讨论了炫目体色可能与动物小型体型演化相关的潜在原因。