Data from: High genetic variation in resting stage production in a metapopulation: is there evidence for local adaptation?

Local adaptation is a key process for the maintenance of genetic diversity and population diversification. A better understanding of the mechanisms that allow (or prevent) local adaptation constitutes a key in apprehending how and at what spatial scale it occurs. The production of resting stages is found in many taxa and reflects an adaptation to outlast adverse environmental conditions. Daphnia magna (Crustacea) can alternate between asexual and sexual reproduction, the latter being linked to dormancy, as resting stages can only be produced sexually. In this species, on a continental scale, resting stage production is locally adapted, i.e. it is induced when the photoperiod indicates the imminence of habitat deterioration. Here, we aimed to explore whether selection is strong enough to maintain local adaptation at a scale of a few kilometers. We assessed life history traits of 64 D. magna clones originating from 11 populations of a meta-population with permanent and intermittent pool habitats. We found large within- and between-population variation for all dormancy-related traits, but no evidence for the hypothesised higher resting stage production in animals from intermittent habitats. We discuss how gene flow, founder events or other forms of selection might interfere with the process of local adaptation.局部适应（local adaptation）是维持遗传多样性与种群分化的核心过程。深入解析介导或抑制局部适应的机制，是明晰其发生方式与空间尺度的关键所在。诸多生物类群均可产生休眠阶段（resting stage），该特征是其适应恶劣环境、得以渡过逆境的策略体现。大型溞（Daphnia magna，隶属于甲壳纲（Crustacea））可在无性繁殖与有性繁殖之间交替进行，其中有性繁殖与休眠过程紧密关联，因为休眠阶段仅能通过有性生殖产生。在该物种中，大陆尺度下的休眠阶段产生过程呈现局部适应性：即当光周期信号预示生境即将恶化时，该过程便会被诱导启动。本研究旨在探究：在数公里的空间尺度下，选择压力是否足够强大以维持局部适应性。我们对源自包含永久性与间歇性两类池生生境的11个集合种群（meta-population）的64个大型溞克隆株系的生活史性状进行了测定。研究结果显示，所有与休眠相关的性状均存在显著的种群内与种群间变异，但未发现支持“间歇性生境来源的个体休眠阶段产生量更高”这一假说的实验证据。我们进一步探讨了基因流、奠基者事件及其他形式的选择可能如何干扰局部适应进程。