Data from: Color change for thermoregulation versus camouflage in free-ranging lizards

Animal coloration has multiple functions including thermoregulation, camouflage, and social signaling, and the requirements of each function may sometimes conflict. Many terrestrial ectotherms accommodate the multiple functions of color through color change. However, the relative importance of these functions and how color-changing species accommodate them when they do conflict are poorly understood because we lack data on color change in the wild. Here, we show that the color of individual radio-tracked bearded dragon lizards, Pogona vitticeps, correlates strongly with background color and less strongly, but significantly, with temperature. We found no evidence that individuals simultaneously optimize camouflage and thermoregulation by choosing light backgrounds when hot or dark backgrounds when cold. In laboratory experiments, lizards showed both UV-visible (300–700 nm) and near-infrared (700–2,100 nm) reflectance changes in response to different background and temperature treatments, consistent with camouflage and thermoregulatory functions, respectively, but with no interaction between the two. Overall, our results suggest that wild bearded dragons change color to improve both thermoregulation and camouflage but predominantly adjust for camouflage, suggesting that compromising camouflage may entail a greater potential immediate survival cost.

动物体色具有多重功能，包括体温调节、伪装以及社会信号传递，且各功能的需求有时会相互冲突。许多陆生外温动物通过体色变化来协调体色的多重功能。然而，由于缺乏野外环境下的体色变化数据，学界对这些功能的相对重要性，以及体色可变物种在功能冲突时如何协调这些功能的机制仍知之甚少。本研究对经无线电追踪的个体鬃狮蜥（*Pogona vitticeps*）进行分析后发现，其体色与背景颜色呈强相关，与温度则呈较弱但显著的相关关系。我们未发现个体可通过在体温较高时选择浅色背景、体温较低时选择深色背景，同时优化伪装与体温调节功能的证据。在实验室实验中，鬃狮蜥的紫外-可见光（300–700 nm）与近红外光（700–2100 nm）反射率均会因不同背景与温度处理发生变化，分别对应伪装与体温调节功能，但二者之间不存在交互效应。综合来看，我们的研究结果表明，野生鬃狮蜥通过改变体色同时实现体温调节与伪装优化，但主要以伪装适配为首要调整目标，这提示牺牲伪装可能会带来更高的即时生存潜在成本。