Data from: Between-population differences in multi-stressor tolerance during embryo development in the American horseshoe crab, Limulus polyphemus

The American horseshoe crab, Limulus polyphemus, is found along the Atlantic and Gulf of Mexico coasts in genetically-isolated populations. Eggs are laid in shoreline beaches that expose developing embryos to combinations of environmental stressors. Whether populations of L. polyphemus differ in multi-stressor tolerance had never been tested. We assessed the multi-stressor tolerance of L. polyphemus embryos from a population in Delaware Bay (DE) and determined whether these differed from the multi-stressor tolerance of embryos from a more southerly Florida Gulf Coast (FGC) population. We monitored the field sediment temperatures and determined multi-stressor tolerance of DE embryos, then compared these to published data for FGC embryos. For multi-stressor tolerance, we assessed development success of embryos in two-week exposures to 36 fully-factorial combinations of temperature (20, 25, 30, 35 °C), salinity (5, 15 and 34 ppt) and ambient O2 (5, 13 and 21% O2), followed by two-weeks in recovery conditions. Sediment temperatures in the DE site ranged from 9.5-46 °C, with extended periods exceeding 35 °C. Development success was similar between the DE and FGC populations in 14 of 26 multi-stressor combinations. The DE embryos were generally more successful in conditions that included high temperature or moderate hyposalinity, whereas the FGC embryos were generally more successful in conditions that included extreme hyposalinity. This suggests that although multi-stressor tolerances are generally similar between the two populations, specific differences exist that correlate more with differences in nest microenvironment than latitude.美洲鲎（American horseshoe crab, Limulus polyphemus）沿大西洋及墨西哥湾沿岸分布，存在遗传隔离的种群。该物种将卵产于近岸海滩，使发育中的胚胎暴露于多种环境胁迫因子的联合作用中。此前尚未有研究检验美洲鲎种群对多重胁迫的耐受性是否存在差异。本研究评估了特拉华湾（DE）种群的美洲鲎胚胎的多重胁迫耐受性，并对比了其与更偏南的佛罗里达湾海岸（FGC）种群胚胎的多重胁迫耐受性差异。我们监测了特拉华湾样地的沉积物温度，并测定了DE种群胚胎的多重胁迫耐受性，随后将其与已发表的FGC种群胚胎相关数据进行比对。在多重胁迫耐受性测定实验中，我们将胚胎置于温度（20、25、30、35 ℃）、盐度（5、15和34 ppt）以及环境氧气（5%、13%和21% O₂）的36种全因子组合环境中暴露两周，随后转移至恢复培养条件中继续培养两周，以评估其发育成功率。特拉华湾样地的沉积物温度范围为9.5~46 ℃，且存在持续时长不等的超过35 ℃的时段。在26种多重胁迫组合中，DE与FGC种群的胚胎发育成功率在其中14种组合中无显著差异。DE种群胚胎在高温或中度低盐胁迫条件下的发育成功率普遍更高，而FGC种群胚胎则在极端低盐胁迫条件下表现更优。这表明尽管两个种群的多重胁迫耐受性总体相似，但仍存在特异性差异，且这些差异与巢穴微环境的差异关联程度高于与纬度的关联。