Tag: sea stars

Guard Crabs Defend Coral Reefs from Predatory Sea Star Army

Guard Crabs Defend Coral Reefs from Predatory Sea Star Army

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Embattled coral reefs in French Polynesia have found a colorful ally in crabs. In exchange for shelter and secreted nutrients, different species of coral guard-crabs fiercely defend their coral hosts against corallivores ranging in size (and voraciousness) from giant predaceous starfish to small sea snails. The work was published in PeerJ this week. Crown-of-thorns sea stars (Acanthaster planci), which grow to the size of trashcan lids, can threaten entire reef communities. After inverting its stomach, the sea star drapes it over a coral and secretes digestive enzymes that dissolve the coral tissue, which is then absorbed by the stomach. But if the coral is housing guard-crabs from the genus Trapezia, they’ll emerge to pinch, shake, and nip off the sea star’s tube-li