A Drosophila laboratory evolution experiment points to low evolutionary potential under increased temperatures likely to be experienced in the future

The ability to respond evolutionarily to increasing temperatures is important for survival of ectotherms in a changing climate. Recent studies suggest that upper thermal limits may be evolutionary constrained. We address this hypothesis in a laboratory evolution experiment, encompassing ecologically relevant thermal regimes. To examine the potential for species to respond to climate change, we exposed replicate populations of Drosophila melanogaster to increasing temperatures (0.3 °C every generation) for 20 generations, whereas corresponding replicate control populations were held at benign thermal conditions throughout the experiment. We hypothesized that replicate populations exposed to increasing temperatures would show increased resistance to warm and dry environments compared with replicate control populations. Contrasting replicate populations held at the two thermal regimes showed (i) an increase in desiccation resistance and a decline in heat knock-down resistance in replicate ...

在气候变化背景下，对温度升高产生进化响应的能力，对于变温动物（ectotherms）的生存至关重要。近期研究表明，物种的高温上限可能受到进化约束。本研究通过一项涵盖生态学相关温度处理体系的实验室进化实验，对该假说进行验证。为探究物种响应气候变化的潜力，我们将黑腹果蝇（Drosophila melanogaster）的重复种群置于温度逐代升高（每代升高0.3℃）的环境中培养20代；与此同时，对应的对照重复种群则在整个实验期间均维持于适宜温度条件下。我们提出假说：与对照重复种群相比，经历温度逐代升高的重复种群，其对温热与干旱环境的抗性将有所提升。对两种温度处理体系下的重复种群进行对比分析后发现：（1）实验种群的抗干燥抗性显著提升，而热击倒抗性则出现下降……