FACTORS AFFECTING THE SHELL ASSESSMENT BEHAVIOR OF THE HERMIT-CRAB, CALCINUS-TIBICEN (HERBST, 1791) (DECAPODA, PAGURIDEA)

Factors influencing shell assessment behaviour were studied in the hermit crab, Calcinus tibicen. Visual and chemical presence of potential competition significantly lengthened the duration of shell assessment. Shell genus occupied by the hermit crab also had a significant effect. Those in Astrea shells examined an offered Cerithium shell significantly longer than hermit crabs occupying Cerithium, Pisania, or Nerita shells. Shell deficit, the difference between optimal shell volume for the hermit crab and actual shell volume, did not have a significant effect on the behavior of the hermit crabs occupying Cerithium shells. For those in Pisania shells there was a negative correlation between shell deficit and shell examination; while crabs in Nerita and Astrea shells demonstrated a positive correlation between shell deficit and shell examination. Neither the sex of the individual crab nor the presence of a predator, Calappa flammea, had a significant effect on shell assessment behaviour.