Shell preference and utilization patterns in littoral hermit crabs of the bay of Panama

Abstract

Shell utilization patterns of three sympatric hermit crab species from the Bay of Panama are examined. Shell preferences, as shown by laboratory choice experiments and the selective use of empty shells experimentally added to hermit crab populations, are shown to be important determinants of shell utilization under natural conditions. Factors which influence the types and sizes of shells occupied by hermit crabs in separate populations include: (1) the presence and relative abundance of different gastropod species; (2) the specific shell preferences of different hermit crab species; and (3) the presence and relative abundance of sympatric hermit crab competitors for the limited supply of empty shells. Since the size and type of shell occupied by a hermit crab influences its growth rate and reproductive output, these factors appear to have a direct effect on hermit crab fitness and the demographic structure of separate hermit crab populations.