Chipmunk body mass variations and life-histories in a pulsed resource ecosystem

Phenotypic plasticity is the most immediate mechanism of adaptative response to environmental change. Studying plastic changes in response to fluctuating environments provides insights into how such adjustments may impact life-history traits. Here, we used a 14-year dataset of repeated body mass measurements in male eastern chipmunks (Tamias striatus) to assess the extent of plastic changes for this trait in a resource pulse ecosystem. We first determined the magnitude of variation in body mass at the population level in response to the drastic change in food resource availability from American beech tree seeds (Fagus grandifolia). Males that emerged in the spring from winter torpor following a non-mast year had a lower body mass than males emerging after a mast year, but they tended to recover this loss by mid-June. We found significant among-individual variation in spring body mass plasticity (i.e., individual by environment interaction, I x E). We then investigated the relationships ...

表型可塑性（phenotypic plasticity）是生物体响应环境变化最直接的适应性机制。探究生物体对波动环境的塑性响应变化，有助于揭示这类调整如何影响其生活史性状。本研究依托一项针对雄性东部花栗鼠（Tamias striatus）长达14年的体质量重复监测数据集，旨在评估该物种在资源脉冲生态系统中体质量性状的塑性变化幅度。我们首先从种群水平分析了体质量随美洲山毛榉（Fagus grandifolia）种子资源可获得性剧变的变化幅度：在非大年结实年份春季从冬季蛰伏（winter torpor）中苏醒的雄性个体，其体质量显著低于大年结实年份后苏醒的雄性个体，但二者的体质量差异会在6月中旬得到显著恢复。我们发现春季体质量可塑性存在显著的个体间差异（即个体-环境互作，I×E）。随后我们进一步探讨了相关关系……