Transfer of the gatekeeper sea anemone Verrillactis sp. (Cnidaria: Actiniaria: Sagartiidae) between shells by the host hermit crab Dardanus deformis (H. Milne Edwards, 1836) (Decapoda: Anomura: Diogenidae)

摘要

The symbiotic association between hermit crabs and sea anemones is a classic example of mutualism in the sea. Some species of hermit crabs have the ability to transfer the symbiotic anemones onto their new shells when they change shells. The hermit crab Dardanus deformis (H. Milne Edwards, 1836) (Decapoda: Diogenidae) carries some anemones on the dorsal surface of the shell (e.g, Calliactis) it inhabits and frequently has the sea anemone Verrillactis sp. (most probably conspecific with "Verrillactispaguri" in Uchida and Soyama, 2001) placed at the shell aperture. In this study, we observed that D. deformis transferred Verrillactis sp. from the aperture of its old shell to that of its new shell. This suggests that the peculiar position of Verrillactis sp. is determined by the hermit crab, which recognizes its proper position. Dardanus deformis engaged in a specific behavior of tapping before transferring Verrillactis sp. to the new shell. This is similar to the behavior shown previously by D. deformis to remove the sea anemones of Calliactis (Hormathiidae) from the dorsal surface of the shell. This suggests that this hermit crab species evolved a very similar tactile process for communication between the different Sagartiidae and Hormathiidae lineages of sea anemones.