Patterns of Shell Resource Utilization by Terrestrial Hermit Crabs at Enewetak Atoll, Marshall Islands

Abstract

Patterns of gastropod shell utilization by Coenobita perlatus and C. rugosus were investigated on three islets of Enewetak Atoll, Marshall Islands. Habitat, hermit crab size, and hermit crab species all influenced the utilization of shells by Coenobita. Small crabs ( < 8mm carapace length) used 63 shell species, while large hermit crabs ( > 19mm) used only two species. Coenobita perlatus occupied long, narrow shells (e.g. , Rhinoclavis) more frequently than C. rugosus. By contrast, C. rugosus used shorter shells (e.g., Nerita) more frequently. Reproduction of C. rugosus, both the percentage of ovigerous females and fecundity, was not influenced by the shell species occupied.