Aspects of the growth and reproduction of the coral gall crab Hapalocarcinus marsupialis

摘要

Growth and reproduction were studied in the coral gall crab Hapalocarcinus marsupialis from fringing reefs in the Egyptian Red Sea. The host coral was Stylophora pistillata. The galls were divided into five stages, and the later stages contained larger crabs and a higher proportion of ovigerous females. Female crabs ranged from 1.17 to 5.33 mm in carapace width. They matured at about 2.5-mm carapace width (probably in the fourth instar); maturity was indicated by an increase in abdomen size, ripening ovaries, mating, and egg laying. The largest females were probably in the seventh instar. After maturity females survived for some 10 months and were ovigerous for 80% of that time, producing eight or more broods. These were all fertilised from the original mating. Reproductive investment was high, both per brood and per year.