Dietary effects on larval survival and development of three sesarmid crabs

Semi-terrestrial brachyuran sesarmid crabs are the most diverse and important faunal components of man-grove forest and temperate coastal communities worldwide. To establish a stable larval rearing method for understand-ing their larval developmental processes including molecular mechanisms of molting and metamorphosis, we examined the effects of diet on the survival and growth of three sesarmid crabs, Chiromantes haematocheir, Orisarma intermedi-um, and O. dehaani under larval development. Zoea of each species, immediately after hatching, were reared under dif-ferent feeding conditions as follows: non-feeding; fed only nutrition-enriched rotifers; fed only Artemia (brine shrimp) nauplii; and fed a combination of both nutrition-enriched rotifers and brine shrimp. Larvae of each species survived almost to megalopa when they were fed both rotifer and brine shrimp, but all C. haematocheir larvae had died by zoeal stage 2 when they were only fed brine shrimp. Chiromantes haematocheir larvae could survive into the megalopa stage when fed only nutrition-enriched rotifer, whereas both O. dehaani and O. intermedium showed 50% or less survival and metamorphosis rates into megalopa. The duration of larval development and survival rates of the three crabs were shorter and higher, respectively, in the mixed feeding group (both rotifer and brine shrimp) than when only fed rotifer or brine shrimp. This study provides baseline knowledge of the interspecific variability in larval survival and duration under different diets for sympatric sesarmid crab species.