Extreme Insolation: Climatic Variation Shapes the Evolution of Thermal Tolerance at Multiple Scales
Extreme Insolation: Climatic Variation Shapes the Evolution of Thermal Tolerance at Multiple Scales
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DOI：
10.1086/698656
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发表时间：
2018-09-01
影响因子：
2.9
通讯作者：
O'Donnell, Sean
中科院分区：
文献类型：
--
作者：
Baudier, Kaitlin M.;D'Amelio, Catherine L.;O'Donnell, Sean
气候变异性假说（CVH）是热生态学的基石，预测在更多变的环境中更广泛的生物热耐受范围的演变。热公差范围取决于公差上限和下限（临界热最大值[CTmax？]和临界热最小值[CTmin？]），其可以显示对环境梯度的不同响应。为了描述平均温度和极端温度对耐热性的相对影响，我们在多个尺度上对行军蚁（Dorylinae）的CVH预测进行了一个纬度内的比较测试：跨海拔，季节性与季节性森林，地下与地表微生境。与CVH一致，热缓冲的地下物种具有较窄的耐热范围。两个CTmin？CTmax？地下种随海拔升高而减少。与此相反，地上物种（那些暴露于太阳辐射）表现出减少CTmin？但CT最大值无变化？跨越海拔。此外，更大的季节性温度变化在干燥的森林与增加CTmax？而不是CTmin？。这些模式表明，CTmax？而CTmin？响应不同的非生物选择力：栖息地特定的极端日照暴露对应CTmax？差异，而不是CTmin？变化量我们预测，与气候变化相关的日益频繁的热峰将对变温动物产生特定于栖息地的生理后果。预测气候变化影响的模型应考虑到物种的微生境利用和温度季节性的纬度差异。
The climatic variability hypothesis (CVH) is a cornerstone of thermal ecology, predicting the evolution of wider organismal thermal tolerance ranges in more thermally variable environments. Thermal tolerance ranges depend on both upper and lower tolerance limits (critical thermal maxima [CTmax?] and critical thermal minima [CTmin?]), which may show different responses to environmental gradients. To delineate the relative effects of mean and extreme temperatures on thermal tolerances, we conducted a within-latitude comparative test of CVH predictions for army ants (Dorylinae) at multiple scales: across elevations, in seasonal versus aseasonal forests, and in subterranean versus surface microhabitats. Consistent with the CVH, thermally buffered subterranean species had narrower thermal tolerance ranges. Both CTmin? and CTmax? decreased with elevation for subterranean species. In contrast, aboveground species (those exposed to insolation) showed a decrease in CTmin? but no change in CTmax? across elevations. Furthermore, greater seasonal temperature variation in dry forests correlated with increased CTmax? but not CTmin?. These patterns suggest that CTmax? and CTmin? respond to different abiotic selective forces: habitat-specific exposure to extreme insolation corresponds to CTmax? differences but not to CTmin? variation. We predict that increasingly frequent heat spikes associated with climate change will have habitat-specific physiological consequences for ectothermic animals. Models predicting climate change impacts should account for species microhabitat uses and within-latitude differences in temperature seasonality.