Data from: Basking behavior predicts the evolution of heat tolerance in Australian rainforest lizards

There is pressing urgency to understand how tropical ectotherms can behaviorally and physiologically respond to climate warming. We examine how basking behavior and thermal environment interact to influence evolutionary variation in thermal physiology of multiple species of lygosomine rainforest skinks from the Wet Tropics of northeastern Queensland, Australia (AWT). These tropical lizards are behaviorally specialized to exploit canopy or sun, and are distributed across steep thermal clines in the AWT. Using phylogenetic analyses, we demonstrate that physiological parameters are either associated with changes in local thermal habitat or to basking behavior, but not both. Cold tolerance, the optimal sprint speed, and performance breadth are primarily influenced by local thermal environment. Specifically, montane lizards are more cool tolerant, have broader performance breadths, and higher optimum sprinting temperatures than their lowland counterparts. Heat tolerance, in contrast, is strongly affected by basking behavior: there are two evolutionary optima, with basking species having considerably higher heat tolerance than shade skinks, with no effect of elevation. These distinct responses among traits indicate the multiple selective pressures and constraints that shape the evolution of thermal performance. We discuss how behavior and physiology interact to shape organisms' vulnerability and potential resilience to climate change.

当前亟需阐明热带外温动物（ectotherms）如何通过行为与生理途径响应气候变暖。本研究旨在解析晒背行为（basking behavior）与热环境如何共同作用，进而影响澳大利亚昆士兰州东北部湿热带地区（Wet Tropics of northeastern Queensland, Australia，以下简称AWT）内多种光蜥亚科（Lygosominae）雨林石龙子的热生理演化差异。这些热带蜥蜴具备特化的生境利用行为策略：部分类群依赖林冠遮阴，另一部分则偏好日光直射，且在AWT范围内分布于陡峭的热梯度（thermal clines）环境中。本研究通过系统发育分析（phylogenetic analyses）证实，石龙子的生理参数仅与局部热生境变化或晒背行为相关，无法同时受二者共同影响。耐寒性（cold tolerance）、最优疾跑速度（optimal sprint speed）以及性能广度（performance breadth）主要受局部热生境调控。具体而言，山地蜥蜴相较于低地同类，具备更强的耐寒性、更宽的性能广度，以及更高的最优疾跑温度。与之相反，耐热性（heat tolerance）则主要受晒背行为调控：该性状存在两类演化最优型，依赖晒背的石龙子相较于遮阴型石龙子（shade skinks）具备显著更高的耐热性，而海拔因素对其无显著影响。不同性状的差异化响应模式，揭示了塑造热性能演化的多重选择压力与演化限制因素。本研究还探讨了行为与生理如何共同作用，进而决定生物对气候变暖的脆弱性与潜在恢复能力。