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Hermit Crabs: Behavioral Economics of Resource Use

Hermit crabs live inside snail shells, which offer shelter from predators and desiccation. Because they constantly require new shells as they grow larger, hermit crabs have evolved specialized behaviors for evaluating and acquiring suitable shells. Our research has centered on the behavioral economics of resource use by hermit crabs, including shell choice and vacancy chains. In hermit crab vacancy chains, an empty shell triggers a chain of sequential vacancies that can distribute new shell resources across many individuals. Vacancy chains involve unique behavioral patterns for resource acquisition that determine how reusable resources, in this case shells, get distributed through human and animal populations.

Our studies using the terrestrial soldier crab, Coenobita clypeatus, confirm the theoretical prediction that vacancy chains should benefit participating individuals. Our work has also detected and described two distinct types of vacancy chain, synchronous and asynchronous, each predicted to carry different behavioral and ecological costs and benefits. Our field studies and laboratory experiments have revealed new hermit crab social behaviors that appear central to understanding the formation of these vacancy chains.

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