Reproductive biology of the hermit crab Pagurus middendorffii Brandt (Decapoda: Anomura: Paguridae)

Abstract

Reproductive biology of the hermit crab Pagurus middendorffii was studied from August 1992 to January 1994 in Kattoshi, located along the west side of Hakodate Bay, Hokkaido, Japan. Its mating season was from late October to early December with a peak in early November. Ovigerous females were observed from October to March, with highest frequencies occurring from December to February (mean: 91.3%). Developmental stages of incubated eggs were synchronized within the population. Females were found to be able to reproduce in their first year and laying a single clutch each following year. Incubation period was about 3.5 months. While ovigerous females did not molt from November to March, male molting frequency was also low during the female incubation period. The covariation of male and female molt frequencies suggests that females do not necessarily have a growth disadvantage due to molt cessation during incubation.