Koussoroplis Apostolos-Manuel, Wacker Alexander
Institute for Biochemistry and Biology, Potsdam University, Potsdam, Germany.
Ecol Lett. 2016 Feb;19(2):143-152. doi: 10.1111/ele.12546. Epub 2015 Nov 27.
Understanding animal performance in heterogeneous or variable environments is a central question in ecology. We combine modelling and experiments to test how temperature and food availability variance jointly affect life-history traits of ectotherms. The model predicts that as mean temperatures move away from the ectotherm's thermal optimum, the effect size of joint thermal and food variance should become increasingly sensitive to their covariance. Below the thermal optimum, performance should be positively correlated with food-temperature covariance and the opposite is predicted above it. At lower temperatures, covariance should determine whether food and temperature variance increases or decreases performance compared to constant conditions. Somewhat stronger than predicted, the covariance effect below the thermal optimum was confirmed experimentally on an aquatic ectotherm (Daphnia magna) exposed to diurnal food and temperature variance with different amounts of covariance. Our findings have important implications for understanding ectotherm responses to climate-driven alterations of thermal mean and variance.
了解动物在异质或多变环境中的表现是生态学中的一个核心问题。我们结合建模和实验来测试温度和食物可利用性的变化如何共同影响变温动物的生活史特征。该模型预测，随着平均温度偏离变温动物的热最适温度，热和食物变化的联合效应大小应该对它们的协方差越来越敏感。在热最适温度以下，表现应该与食物 - 温度协方差呈正相关，而在其之上则预测相反。在较低温度下，协方差应决定与恒定条件相比，食物和温度变化是增加还是降低表现。在一种暴露于具有不同协方差量的昼夜食物和温度变化的水生变温动物（大型溞）上，实验证实了热最适温度以下的协方差效应，其强度略强于预测。我们的发现对于理解变温动物对气候驱动的热均值和变化改变的反应具有重要意义。
