USE OF CHEMICAL CUES FOR SHELL PREFERENCE BY THE HERMIT-CRAB, PAGURUS-SAMUELIS

A series of experiments tested shell recognition ability of the hermit crab Pagurus samuelis. When presented with a choice between its origi nal shell and another matched gastropod shell not previously inhabited by a hermit crab, P. samuelis chose its original shell. However, when a crab was presented with a choice between its boiled original shell and a boiled shell without prior hermit crab inhabitants, or the boile d shell of another crab, it lost its preference for its original shell . These experiments indicate that preference for the original shell by the crab is dependent on chemical, but not visual cues, and that thes e chemical cues are eliminated by boiling. In addition, P. samuelis di splayed the ability to detect its original shell versus the shell from a conspecific. Crabs preferred their original shells. No difference w as found in tests where a crab was given a choice between the scent of itself without a shell, and the scent of another shell-less crab. Thi s indicates that the cue for original shell preference is in some mann er associated with the crab's shell.