Data from: Rapid change in the thermal tolerance of a tropical lizard

The predominant view is that the thermal physiology of tropical ectotherms, including lizards, is not labile over ecological timescales. We used the recent introduction (∼35 years ago) of the Puerto Rican lizard Anolis cristatellus to Miami, Florida, to test this thermal rigidity hypothesis. We measured lower (critical thermal minimum [CTmin]) and upper (critical thermal maximum [CTmax]) thermal tolerances and found that the introduced population tolerates significantly colder temperatures (by ∼3°C) than does the Puerto Rican source population; however, CTmax did not differ. These results mirror the thermal regimes experienced by each population: Miami reaches colder ambient temperatures than Puerto Rico, but maximum ambient temperatures are similar. The differences in CTmin were observed even though lizards from both sites experienced nearly identical conditions for 49 days before CTmin measurement. Our results demonstrate that changes in thermal tolerance occurred relatively rapidly (∼35 generations), which strongly suggests that the thermal physiology of tropical lizards is more labile than previously proposed.当前学界主流观点认为，包括蜥蜴在内的热带变温动物（ectotherms）的热生理学特性，在生态时间尺度上并不具备易变性。我们以约35年前被引入美国佛罗里达州迈阿密的波多黎各变色安乐蜥（Anolis cristatellus）为研究对象，对这一热刚性假说进行了检验。我们测定了两类种群的临界低温（critical thermal minimum, CTmin）与临界高温（critical thermal maximum, CTmax），结果发现，迈阿密引入种群较其波多黎各源种群可耐受低约3℃的低温，但二者的临界高温并无显著差异。上述结果与两个种群所经历的热环境特征高度吻合：迈阿密的环境最低温低于波多黎各，但两地的环境最高温较为相似。即便两地蜥蜴在临界低温测定前的49天内均处于几乎一致的饲养条件，二者的临界低温差异依然显著。本研究结果表明，热耐受性的变化可在相对较短的时间内（约35个世代）发生，这有力地证明热带蜥蜴的热生理学特性比此前学界所认为的更具可塑性。