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.

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（thermal physiology）在生态时间尺度上并不具备易变性。本研究以约35年前被引种至美国佛罗里达州迈阿密的波多黎各冠安乐蜥（Anolis cristatellus）为实验对象，对这一热刚性假说展开验证。我们测定了两类种群的临界最低热耐受温度（critical thermal minimum, CTmin）与临界最高热耐受温度（critical thermal maximum, CTmax），结果显示引种种群的低温耐受能力显著优于波多黎各源种群（温差约3℃），但二者的CTmax并无显著差异。该结果与两个种群各自所处的热环境条件相契合：迈阿密的环境最低温度低于波多黎各，但两地的环境最高温度相近。即便在CTmin测定前的49天内，两地来源的蜥蜴均处于近乎一致的饲养环境中，我们仍观测到了二者在CTmin上的显著差异。本研究结果表明，热耐受能力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比此前研究所提出的更具易变性。