Data from: Life-history plasticity in female threespine stickleback

The postglacial adaptive radiation of the threespine stickleback fish (Gasterosteus aculeatus) has been widely used to investigate the roles of both adaptive evolution and plasticity in behavioral and morphological divergence from the ancestral condition represented by present-day oceanic stickleback. These phenotypes tend to exhibit high levels of ecotypic differentiation. Population divergence in life history has also been well studied, but in contrast to behavior and morphology, the extent and importance of plasticity has been much less well studied. In this review, we summarize what is known about life-history plasticity in female threespine stickleback, considering four traits intimately associated with reproductive output: age/size at maturation, level of reproductive effort, egg size and clutch size. We envision life-history plasticity in an iterative, ontogenetic framework, in which females may express plasticity repeatedly across each of several time frames. We contrast the results of laboratory and field studies because, for most traits, these approaches give somewhat different answers. We provide ideas on what the cues might be for observed plasticity in each trait and, when possible, we inquire about the relative costs and benefits to expressed plasticity. We end with an example of how we think plasticity may play out in stickleback life history given what we know of plasticity in the ancestor.

三刺棘鱼（Gasterosteus aculeatus）的冰后适应性辐射，已被广泛用于探究适应性进化与可塑性在行为和形态分化中的作用——这类分化的祖先状态以现存海洋棘鱼为代表。这类表型往往呈现出高度的生态型分化。生活史相关的种群分化也已得到充分研究，但与行为和形态特征不同的是，有关可塑性的程度与重要性的研究却相对匮乏。在本综述中，我们系统总结了当前关于雌性三刺棘鱼生活史可塑性的研究进展，重点聚焦于与繁殖产出紧密相关的四项特征：成熟时的年龄与体型、繁殖投入水平、卵粒大小以及窝卵数。我们将生活史可塑性置于迭代式的个体发育框架中进行分析，即雌性个体可在多个时间维度下反复表现出可塑性。鉴于针对多数特征，实验室与野外研究的结果存在一定差异，我们对两类研究的结论进行了对比。此外，我们针对各特征下已观测到的可塑性提出了潜在的触发线索，并在可行的前提下探讨了该可塑性表现所对应的相对成本与收益。最后，我们结合对祖先种群可塑性的认知，通过一则实例阐释了可塑性在棘鱼生活史中的潜在作用模式。