INTERSPECIFIC SHELL TRANSFER BY MUTUAL PREDATION SITE ATTENDANCE

The hermit crabs Clibanarius vittatus and Pagurus pollicaris overlap c onsiderably in the species of gastropod shells occupied. Patterns of e pibionts on shells suggested interspecific transfer between the crab s pecies. In laboratory observations, however, even when crabs were high ly motivated to get new shells, no direct transfers occurred. This lac k of exchanges is correlated with different shell exchange behaviour p atterns of the two crab species. When simulated snail predation sites were set up in the laboratory and in the field, indirect interspecific transfers were observed as crabs moved from occupied shells to recent ly vacated shells. (C) 1996 The Association for the Study of Animal Be haviour.