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。在此类情境下，能够适应新生态位的物种得以存续，甚至扩张其分布范围。然而，基因流（gene flow）会阻碍物种对新环境的遗传适应。与之相对，近期的研究模型强调了表型可塑性（phenotypic plasticity）在应对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一两栖类物种利用两种截然不同的气候生态位。在地中海区域，香菜蛙（parsley frog，Pelodytes punctatus）的繁殖期既有春季（与多数其他两栖类一致），也有秋季——这一时段生态位未被多数其他物种占据，但随着全球变暖，该时段的重要性正日益凸显。两个繁殖季的发育环境差异悬殊，会对蝌蚪的生活史性状产生深刻影响。为探明这些时段生态位究竟由两个遗传分化的亚种群所利用，还是在具有可塑性生活史性状的随机交配种群（panmictic population）中诞生了双峰物候现象，本研究采用了两种互补的研究方法。我们分别利用微卫星标记（microsatellites）和共同花园实验（common garden experiments），检测了春季与秋季繁殖群之间的分子遗传分化与数量性状分化。各季节繁殖群并未出现遗传分化，且蝌蚪生活史的组间差异在实验室培养条件下并未持续存在。综上，本研究认为，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段生态位。