Data from: Phenotypic plasticity allows the Mediterranean parsley frog Pelodytes punctatus to exploit two contrasted temporal niches under continuous gene flow

Environmental changes, such as climate change, lead to the opening of new niches. In such situations, species that adapt to new niches can survive and/or expand their ranges. However, gene flow can hamper genetic adaptation to new environments. Alternatively, recent models have highlighted the importance of phenotypic plasticity in tracking environmental change. In this study, we illustrate how plasticity allows an amphibian species to exploit two very different climatic niches under continuous gene flow. In the Mediterranean region, the parsley frog Pelodytes punctatus breeds both in spring, as do most other species, and in autumn, a temporal niche not exploited by most other species, but which may become increasingly important with global warming. Conditions of development are dramatically different between the two seasons and deeply impact tadpole life-history traits. To determine whether these temporal niches are exploited by two genetically differentiated sub-populations, or whether the bimodal phenology arises in a panmictic population displaying plastic life-history traits, we use two complementary approaches. We measure both molecular genetic differentiation and quantitative-trait differentiation between spring and autumn cohorts, using microsatellites an common garden experiments respectively. Seasonal cohorts were not genetically differentiated and differences in tadpole life-history between cohorts were not maintained in laboratory conditions. We conclude that phenotypic plasticity, rather than genetic adaptation, allows Parsley frog to exploit two contrasted temporal niches.诸如气候变化在内的环境变化会催生全新的生态位（niche）。在此类情境下，能够适应新生态位的物种得以存续，或是扩张其分布范围。然而，基因流（gene flow）会阻碍物种针对新环境的遗传适应过程。与之相对，近年来的相关模型已凸显出表型可塑性（phenotypic plasticity）在追踪环境变化过程中的重要性。本研究阐明了在持续存在基因流的前提下，表型可塑性如何帮助某两栖类物种利用两种截然不同的气候生态位（climatic niche）。在地中海区域，香菜蛙（Pelodytes punctatus）的繁殖期既与多数其他两栖类一致，在春季产卵，也可选择秋季繁殖——后者是多数其他物种未利用的时间生态位（temporal niche），且随着全球变暖，该繁殖时段的重要性与日俱增。两个繁殖季的发育环境差异悬殊，会对蝌蚪的生活史性状（life-history traits）产生深刻影响。为明确这些时间生态位究竟是由两个遗传分化的亚种群所利用，还是具有可塑性生活史性状的随机交配（panmictic）种群产生了双峰物候现象，本研究采用了两种互补的研究方法。研究分别借助微卫星标记（microsatellites）与共同花园实验（common garden experiment），测定了春季与秋季同生群之间的分子遗传分化与数量性状分化。结果显示，不同季节的同生群之间并无遗传分化；且在实验室可控环境下，蝌蚪生活史性状的组间差异并未得到维持。本研究最终得出结论：正是表型可塑性而非遗传适应，使得香菜蛙能够利用两种截然不同的时间生态位。