Data from: Does genetic variation maintained by environmental heterogeneity facilitate adaptation to novel selection?

Environmental heterogeneity helps maintain genetic variation in fitness. Therefore, one might predict that populations living in heterogeneous environments have higher adaptive potential than populations living in homogeneous environments. Such a prediction could be useful in guiding conservation priorities without requiring detailed genetic studies. However, this prediction will be true only if the additional genetic variation maintained by environmental heterogeneity can be used to respond to novel selection. Here we examine the effect of environmental heterogeneity on future adaptability using replicated experimental Drosophila melanogaster populations that had previously evolved for ∼100 generations under one of four selective regimes: constant salt-enriched larvae medium, constant cadmium-enriched larvae medium, and two heterogeneous regimes that vary either temporally or spatially between the two media. Replicates of these experimental populations were subjected to a novel heat stress while being maintained in their original larval diet selection regimes. Adaptation to increased temperature was measured with respect to female productivity and male siring success after ∼20 generations. For female productivity, there was evidence of adaptation overall and heterogeneous populations had a larger adaptive response than homogeneous populations. There was less evidence of adaptation overall for male siring success and no support for faster adaptation in heterogeneous populations.

环境异质性有助于维持适合度相关的遗传变异。据此可推测，栖息于异质环境的种群，其适应潜力高于均质环境中的种群。该预测无需开展详尽的遗传学研究即可为保护优先级划定提供参考。然而，仅当环境异质性所维持的额外遗传变异可用于应对新的选择压力时，该预测方能成立。本研究以经4种选择方案演化约100代的重复实验黑腹果蝇（Drosophila melanogaster）种群为对象，探究环境异质性对种群未来适应能力的影响。4种选择方案分别为：恒定盐富集幼虫培养基、恒定镉富集幼虫培养基，以及两种分别在两种培养基间随时间或空间变化的异质性处理模式。这些实验种群的重复组在维持原有幼虫培养基选择方案的条件下，接受了新型热胁迫处理。在约20代后，以雌性繁殖力与雄性父本繁殖成功率为指标，衡量种群对温度升高的适应情况。就雌性繁殖力而言，整体观测到显著的适应现象，且异质种群的适应响应幅度大于均质种群。而雄性父本繁殖成功率的整体适应证据相对较弱，且未观测到异质种群适应速度更快的支持证据。