Data from: Evolutionary constraints and the maintenance of individual specialization throughout succession

Constraints on life-history traits, with their close links to fitness, are widely invoked as limits to niche expansion at most organizational levels. Theoretically, such constraints can maintain individual specialization by preventing adaptation to all niches available, but empirical evidence of them remains elusive for natural populations. This problem may be compounded by a tendency to seek constraints involving multiple traits, neglecting their added potential to manifest in trait expression across environments (i.e., within reaction norms). By replicating genotypes of a colonial marine invertebrate across successional stages in its local community, and taking a holistic approach to the analysis of ensuing reaction norms for fitness, we show the potential for individual specialization to be maintained by genetic constraints associated with these norms, which limit the potential for fitness at one successional stage to improve without loss of fitness at others. Our study provides new insight into the evolutionary maintenance of individual specialization in natural populations and reinforces the importance of reaction norms for studying this phenomenon.

生活史性状（life-history traits）与其和适合度（fitness）的紧密关联所形成的约束，在绝大多数组织层次上被广泛视作生态位扩张（niche expansion）的限制因子。从理论层面而言，此类约束可通过阻碍生物对所有可获取生态位的适应，维持个体特化（individual specialization），但针对自然种群的相关实证证据至今仍较为稀缺。该问题可能因研究者倾向于探寻涉及多性状的约束、却忽视了约束在跨环境性状表达（即反应规范（reaction norm））中显现的额外潜力而更为复杂。本研究通过在局域群落的演替阶段中重复培养一种群居海洋无脊椎动物的基因型，并针对由此产生的适合度反应规范采用整体性分析策略，证实了与这些规范相关的遗传约束具备维持个体特化的潜力：这类约束会限制生物在某一演替阶段提升适合度时，不在其他演替阶段出现适合度损失。本研究为自然种群中个体特化的演化维持机制提供了全新视角，并进一步凸显了反应规范在研究该现象时的重要价值。