The purpose of this study was to determine the shell utilization pattern of
Calcinus tibicen using the percentage of the different shell types that we
re occupied, the morphometric relationship between hermit crabs and occupie
d shells, as well as shell availability based on the empty shells and livin
g gastropods observed. Specimens were collected at two-month intervals from
January to November 1998 along the rocky shore of Praia Grande, Ubatuba, u
sing a specific methodology adapted to the irregular surface of the area. O
f 1,069 shells collected, empty shells were less frequent (4.11%) than shel
ls occupied by either hermit crabs (23.11%) or living gastropods (72.78%).
A total of 247 hermit crabs were captured occupying seven of the twelve she
ll species collected in the field. Only Stramonita haemastoma was occupied
in significant numbers (71.26%); There was a differential shell utilization
pattern between sexes; males were most abundant in S. haemastoma shells wh
ile the ovigerous females occupied Leucozonia nassa. Regression analysis sh
owed a close correlation between the dimensions of the crabs and the utiliz
ed shells. In this study, shell occupation by C. tibicen varied as a functi
on of shell type availability, with intraspecific differences in occupation
patterns also occurring.