During tidal cycles, fiddler crabs undergo alternating periods of submersion and desiccation. We compare physiological and biochemical adjustments to submersion and desiccation challenge in two gelasminids from the Galapagos archipelago: the indigenous Leptuca helleri, and Minuca galapagensis . We examine population distributions and habitat characteristics; survival and hemolymph osmolality after 6 h submersion at several salinities, and after 6 or 12 h desiccation; and oxidative stress responses in the hepatopancreas and gills, accompanying glutathione enzyme antioxidant activities, and lipid peroxidation. We provide an integrated biomarker response index based on oxidative stress in each tissue, condition and species. Leptuca helleri occupies a restricted intertidal niche while M. galapagensis is supralittoral. Burrow density in M. galapagensis declined with increasing salinity and decreasing substrate moisture; L. helleri burrow density showed no correlation. After 6 h submersion, L. helleri survived only at 21‰S while M. galapagensis survived from 0 to 42 ‰S. After 6 h desiccation, hemolymph osmolality decreased markedly in L. helleri but increased in M. galapagensis . Antioxidant enzyme activities and lipid peroxidation in the hepatopancreas and gills showed tissue- and species-specific responses to submersion and desiccation challenge. The integrated biomarker response indexes for L. helleri were highest in control crabs, driven by oxidative stress. In M. galapagensis, submersion was the determining factor in both tissues. Minuca galapagensis is a generalist species while Leptuca helleri occupies a more restricted intertidal habitat. The species’ respective physiological limitations and flexibilities provide insights into how fiddler crabs might respond to environmental change on semi-arid islands.

中文翻译：

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半干旱岛屿上的生存策略：来自加拉帕戈斯群岛的招潮蟹的浸没和干燥耐受性

在潮汐周期中，招潮蟹会经历淹没和干燥的交替时期。我们比较了来自加拉帕戈斯群岛的两种gelasminids：本土的Leptuca helleri 和Minuca galapagensis 对浸没和干燥挑战的生理和生化调整。我们检查人口分布和栖息地特征；在几种盐度下浸没 6 小时后以及干燥 6 或 12 小时后的存活率和血淋巴渗透压；和肝胰腺和鳃中的氧化应激反应，伴随着谷胱甘肽酶的抗氧化活性和脂质过氧化。我们提供基于每个组织、状况和物种中的氧化应激的综合生物标志物反应指数。Leptuca helleri 占据有限的潮间带生态位，而 M. galapagensis 则位于沿海。M 中的洞穴密度。galapagensis随着盐度的增加和基质水分的减少而下降；L. helleri 洞穴密度没有显示相关性。浸没 6 小时后，L. helleri 仅在 21‰S 下存活，而 M. galapagensis 在 0 到 42‰S 下存活。干燥 6 小时后，L. helleri 的血淋巴渗透压显着降低，但 M. galapagensis 的血淋巴渗透压升高。肝胰腺和鳃中的抗氧化酶活性和脂质过氧化显示出对浸没和干燥挑战的组织和物种特异性反应。在氧化应激的驱动下，L. helleri 的综合生物标志物反应指数在对照螃蟹中最高。在 M. galapagensis 中，浸没是两种组织中的决定因素。Minuca galapagensis 是一种通才物种，而 Leptuca helleri 占据的潮间带栖息地更为有限。