Effect of salinity on survival and emigration behaviour during the sea-to-land transition of three terrestrial hermit crab species (Decapoda: Anomura: Coenobitidae) under laboratory conditions

抄録

Salinity is an important abiotic factor affecting the survival and development of decapod crustacean larvae and juveniles. We investigated the effect of salinity on survival and emigration behaviour during the sea-to-land transition of three terrestrial hermit crab species in the family Coenobitidae (genera Birgus and Coenobita): B. latro, C. brevimanus and C. purpureus. We cultured laboratory-born individuals from megalopae for 63 days in vessels containing both a hard substrate and seawater controlled at four different salinity levels (25, 30, 35 and 40 ppt). The overall, survival, shell-carrying and landing activities of the animals were enhanced at lower salinity conditions. Interspecific variability in survival and emigration behaviour was evident: C. brevimanus and C. purpureus showed relatively high performance even at higher salinity levels when compared with B. latro, indicating the differences in hypo-osmoregulatory ability among coenobitids. The microhabitats occupied by megalopae and early juveniles of coenobitids could be attributed to the interspecific variability in the osmoregulatory capacity of these animals.