Data from: Multimodal in situ datalogging quantifies inter-individual variation in thermal experience and persistent origin effects on gaping behavior among intertidal mussels (Mytilus californianus)

In complex habitats, environmental variation over small spatial scales can equal or exceed larger-scale gradients. This small-scale variation may allow motile organisms to mitigate stressful conditions by choosing benign microhabitats, whereas sessile organisms may rely on other behaviors to cope with environmental stresses in these variable environments. We developed a monitoring system to track body temperature, valve gaping behavior, and posture of individual mussels (Mytilus californianus) in field conditions in the rocky intertidal zone. Neighboring mussels' body temperatures varied by up to 14°C during low tides. Valve gaping during low tide and postural adjustments, which could theoretically lower body temperature, were not commonly observed. Rather, gaping behavior followed a tidal rhythm at a warm, high intertidal site; this rhythm shifted to a circadian period at a low intertidal site and for mussels continuously submerged in a tidepool. However, individuals within a site varied considerably in time spent gaping when submerged. This behavioral variation could be attributed in part to persistent effects of mussels' developmental environment. Mussels originating from a wave-protected, warm site gaped more widely, and they remained open for longer periods during high tide than mussels from a wave-exposed, cool site. Variation in behavior was modulated further by recent wave heights and body temperatures during the preceding low tide. These large ranges in body temperatures and durations of valve closure events - which coincide with anaerobic metabolism - support the conclusion that individuals experience "homogeneous" aggregations such as mussel beds in dramatically different fashion, ultimately contributing to physiological variation among neighbors.

在复杂生境中，小空间尺度的环境变异幅度可媲美甚至超过大尺度环境梯度。这类小尺度环境变异可使运动型生物通过选择适宜的微生境来缓解胁迫压力，而固着型生物则需借助其他行为策略应对这类多变环境中的环境胁迫。我们研发了一套野外监测系统，用于在潮间带岩礁区（rocky intertidal zone）追踪单个加州贻贝（Mytilus californianus）的体温、双壳张开行为与躯体姿态。低潮期时，相邻贻贝的体温差异最高可达14℃。理论上可降低体温的低潮期双壳张开行为与姿态调整，在观测中并不常见。相反，在温暖的高潮间带站点，双壳张开行为呈现潮汐节律；而在低潮间带站点以及持续浸没于潮池中的贻贝种群中，该节律则转变为昼夜周期。但同一站点内的贻贝个体，在浸没状态下的壳张开时长存在显著差异。这类行为变异部分可归因于贻贝发育环境所产生的持续影响：源自受波浪保护的温暖生境的贻贝，其双壳张开幅度更大，且在高潮期保持壳张开的时长也长于来自波浪暴露型凉爽生境的贻贝。行为变异还会受到近期波高与前次低潮期体温的进一步调控。体温的巨大波动范围与双壳闭合事件的时长差异——该事件与无氧代谢（anaerobic metabolism）相耦合——印证了如下结论：即即便处于诸如贻贝床这类看似‘均质’的聚集体中，不同个体的生存状态仍存在显著差异，最终导致相邻个体间出现生理变异。