Data from: Predictability rather than amplitude of temperature fluctuations determines stress resistance in a natural population of Drosophila simulans

The adaptability of organisms to novel environmental conditions depends on the amount of genetic variance present in the population as well as on the ability of individuals to adjust their phenotype through phenotypic plasticity. Here, we investigated the phenotypic plasticity induced by a single generation’s exposure to three different temperature regimes with respect to several life history and stress resistance traits in a natural population of Drosophila simulans. We studied a constant as well as a predictably and an unpredictably fluctuating temperature regime. We found high levels of phenotypic plasticity among all temperature regimes, suggesting a strong influence of both temperature fluctuations and their predictability. Increased heat tolerance was observed for flies developed in both types of fluctuating thermal environments compared to flies developed in a constant environment. We suggest that this was due to beneficial hardening when developing in either fluctuating temperature environment. To our surprise, flies that developed in constant and predictably changing environments were similar to each other in most traits when compared to flies from the unpredictably fluctuating environment. The unpredictably changing thermal environment imposed the most stressful condition, resulting in the lowest performance for stress related traits, even though the absolute temperature changes never exceeded that of the predictably fluctuating environment. The overall decreased stress resistance of flies in the unpredictably fluctuating environment may be the consequence of maladaptive phenotypic plasticity in this setting, indicating that the adaptive value of plasticity depends on the predictability of the environment.生物体对新型环境条件的适应性，取决于种群中现存的遗传变异量，以及个体通过表型可塑性（phenotypic plasticity）调整自身表型的能力。本研究以自然种群的拟果蝇（Drosophila simulans）为对象，针对多项生活史性状与抗逆相关性状，探究了单一代个体暴露于三种不同温度制度下所诱导的表型可塑性。本研究设置了恒定温度、可预测波动温度以及不可预测波动温度三种处理方案。研究发现所有温度处理下均存在较高水平的表型可塑性，表明温度波动及其可预测性均会产生显著影响。相较于恒定环境下发育的果蝇，两种波动热环境中发育的果蝇均表现出更高的耐热性，我们推测这一现象源于在波动温度环境中发育时产生的有益热硬化效应。令人意外的是，相较于不可预测波动环境下的果蝇，恒定环境与可预测变化环境下发育的果蝇在多数性状上表现相似。尽管不可预测波动热环境的绝对温度变化幅度并未超过可预测波动环境，但其施加的胁迫压力最强，导致抗逆相关性状的表现最差。不可预测波动环境下果蝇整体抗逆性下降，可能是该环境下表型可塑性产生适应不良的结果，这表明可塑性的适应价值取决于环境的可预测性。