Observation of a coral-dwelling gall crab (Cryptochiridae) in a dead coral host highlights their vulnerability to reef degradation

Abstract Coral-associated fauna contributes greatly to coral reef biodiversity. Many species are obligately associated with their hosts on which they depend for food and/or refuge from predators. Their close relationship with their hosts makes them vulnerable to coral mortality. Here I report a coral-dwelling gall crab (Cryptochiridae) inhabiting a partially dead Echinopora Lamarck, 1816 coral, at Magoodhoo Island, Faafu Atoll, Maldives. Cryptochirids are thought to feed off the mucus provided by their coral host, although some questions about their feeding biology remain. This observation highlights that these crabs remain associated with a dead host, even if it can no longer provide nutrients. The strong host association makes gall crabs vulnerable to widespread habitat degradation.

摘要：珊瑚伴生动物区系对珊瑚礁生物多样性的贡献举足轻重。诸多物种与宿主形成专性共生关系，依赖宿主获取食物或躲避天敌。这类动物与宿主的紧密依存关系使其极易受珊瑚死亡事件的影响。本次研究报道了发现于马尔代夫法夫环礁马古杜岛的、栖息于一株部分死亡的棘杯珊瑚属（Echinopora Lamarck, 1816）中的瘿蟹（Cryptochiridae）。尽管学界对隐螯蟹的取食生物学仍存在若干未解疑问，但普遍认为它们以珊瑚宿主分泌的黏液为食。本次观测结果表明，即便宿主已无法提供营养物质，这类螃蟹仍会依附于死亡的宿主。这种极强的宿主依存性使得瘿蟹极易受到大范围栖息地退化的影响。