Data from: Temporal variation favors the evolution of generalists in experimental populations of Drosophila melanogaster

In variable environments, selection should favor generalists that maintain fitness across a range of conditions. However, costs of adaptation may generate fitness trade-offs and lead to some compromise between specialization and generalization that maximizes fitness. Here, we evaluate the evolution of specialization and generalization in 20 populations of Drosophila melanogaster experimentally evolved in constant and variable thermal environments for 3 years. We developed genotypes from each population at two temperatures after which we measured fecundity across eight temperatures. We predicted that constant environments would select for thermal specialists and that variable environments would select for thermal generalists. Contrary to our predictions, specialists and generalists did not evolve in constant and spatially variable environments, respectively. However, temporal variation produced a type of generalist that has rarely been considered by theoretical models of developmental plasticity. Specifically, genotypes from the temporally variable selective environment were more fecund across all temperatures than were genotypes from other environments. These patterns suggest certain allelic effects and should inspire new directions for modeling adaptation to fluctuating environments.

在可变环境中，自然选择应青睐能在多种条件下维持适合度的泛化型类群。然而，适应成本可能引发适合度权衡，并在特化与泛化之间形成某种折中，以实现适合度最大化。本研究以经3年恒定与可变温度环境实验演化的20个黑腹果蝇（Drosophila melanogaster）种群为研究对象，探究特化与泛化的演化规律。我们从每个种群中于两种温度下构建基因型品系，随后在8种温度下测定其繁殖力。我们曾预测，恒定环境会筛选出温度特化型种群，可变环境则会筛选出温度泛化型种群。但与预期相悖的是，恒定环境与空间可变环境中并未分别演化出特化型与泛化型种群。不过，时间可变环境催生了一类此前发育可塑性理论模型极少关注的泛化型类群：具体而言，来自时间可变选择环境的基因型品系，在所有测试温度下的繁殖力均高于其他环境来源的品系。这些结果模式提示了特定的等位基因效应，并可为波动环境适应的建模研究提供新的方向。