抓握能力较强的蜥蜴更可能在飓风后幸存。图片来源：《自然》

近日，一项新研究指出，枝干抓握能力较强的蜥蜴更有可能在飓风后幸存，这是一起正在发生的自然选择事件。

飓风等自然灾害会对生态系统造成毁灭性打击，并导致大量生物死亡。不过，人们尚不清楚飓风导致的死亡是随机性的还是自然对某些物理特性的优先选择，如抗强风能力。

在飓风厄玛和玛利亚毫无预兆地登陆前，美国哈佛大学的Colin Donihue和同事恰巧刚刚在邻近的西印度群岛派恩岛和瓦特岛完成了小型安乐蜥属种群的研究工作。考虑到这是研究飓风对蜥蜴直接影响的难得机会，研究人员在飓风后重回当地进行了跟踪调查，对比了飓风前后安乐蜥的附肢长度和趾垫面积。

该研究小组认为附肢长度和趾垫面积不仅能影响安乐蜥的抓握能力，还与安乐蜥生境利用和运动方式相关。与飓风前相比，派恩岛和瓦特岛上存活下来的蜥蜴平均趾垫更大、前肢更长、后肢更短。

Donihue等人还证实了该种群的趾垫大小和抓握能力具有相关性，并通过拍摄展示了蜥蜴在飓风冲击下如何抓住枝干。虽然较长的前肢更利于抓握，但他们指出，由于蜥蜴在飓风中采取特定的抓握姿势，较长的后肢反而会增加被风吹动的表面积，产生不利影响。相关论文日前刊登于《自然》杂志。

据预测，极端天气在今后几十年的频率和强度都会上升，研究人员因此认为，演化动力学研究应将具有选择性的极端天气纳入考虑范围。（来源：中国科学报 唐一尘）

Hurricane-induced selection on the morphology of an island lizard

Abstract  Hurricanes are catastrophically destructive. Beyond their toll on human life and livelihoods, hurricanes have tremendous and often long-lasting effects on ecological systems. Despite many examples of mass mortality events following hurricanes, hurricane-induced natural selection has not previously been demonstrated. Immediately after we finished a survey of Anolis scriptus—a common, small-bodied lizard found throughout the Turks and Caicos archipelago—our study populations were battered by Hurricanes Irma and Maria. Shortly thereafter, we revisited the populations to determine whether morphological traits related to clinging capacity had shifted in the intervening six weeks and found that populations of surviving lizards differed in body size, relative limb length and toepad size from those present before the storm. Our serendipitous study, which to our knowledge is the first to use an immediately before and after comparison to investigate selection caused by hurricanes, demonstrates that hurricanes can induce phenotypic change in a population and strongly implicates natural selection as the cause. In the decades ahead, as extreme climate events are predicted to become more intense and prevalent, our understanding of evolutionary dynamics needs to incorporate the effects of these potentially severe selective episodes.

原文链接：https://www.nature.com/articles/s41586-018-0352-3.pdf