All data for - Refuge trifecta: intertidal snails use pits to escape heat, wave action, and predation

Refuges play a critical role in ecology and evolution. In hard intertidal shores, small pits attract benthic invertebrates such as gastropods, however, there exists little mechanistic understanding of the processes driving the active usage of these microhabitat features. We conducted a series of laboratory experiments to assess whether the marine snail Nerita undata utilizes pits in concrete tiles as refuges when subjected to simulations of three primary environmental stressors, i.e. temperature, wave action, and predation. The results showed that the fractional time spent in pits (FTpits) by snails was significantly higher when nerites were exposed to stressors compared to when they were absent, indicating that N. undata actively uses artificial pit microhabitats as refuge from temperature, wave action, and predation stress. No difference in FTpits was found between nerites placed on top-surface heated tiles and those placed on homogenously heated tiles, suggesting that the active selection of pits by heat-stressed N. undata was partly attributed to an ability to recognise the physical structure of pits as thermal refuges. These results represent empirical validation to previous field-studies that have made inferences from observations of natural rocky shores and suggest that refuge seeking organisms respond to not only the microenvironment shaped by topographic features but also to the architectural components of topography themselves. Our findings enable a more nuanced understanding of how site-specific stress intensities corresponding with the diel-tidal cycle influence pit refuge utilization patterns and provides evidence that pits serve as a universal refuge for multiple environmental stressors.

庇护所（refuge）在生态学与进化进程中发挥着关键作用。在硬质潮间带海岸，小型坑洼可吸引腹足类（gastropods）等底栖无脊椎动物聚集，但目前对驱动这些生物主动利用此类微生境特征的内在机理仍缺乏清晰认知。我们开展了一系列实验室实验，以评估海洋螺类拟蜒螺（Nerita undata）在经受温度、波浪作用与捕食作用三种主要环境胁迫的模拟处理时，是否会利用混凝土砖上的坑洼作为庇护所。结果显示，与无胁迫对照组相比，拟蜒螺在坑洼中的栖坑时长占比（fractional time spent in pits, FTpits）显著更高，表明N. undata会主动利用人工坑洼微生境以躲避温度、波浪作用与捕食作用带来的胁迫。此外，放置于顶面加热实验砖与均匀加热实验砖上的拟蜒螺，其FTpits并无显著差异，这说明受热胁迫的拟蜒螺对坑洼的主动选择，部分源于其能够识别坑洼的物理结构作为热庇护所。本研究结果为既往基于自然岩质海岸观测开展推断的野外研究提供了实证验证，同时表明寻求庇护的生物不仅会响应地形特征塑造的微环境，还会对地形本身的结构属性做出反应。我们的发现使我们能够更细致地理解与昼夜潮汐周期对应的局地胁迫强度如何影响坑洼庇护所的利用模式，并为坑洼作为应对多种环境胁迫的通用庇护所提供了证据支撑。