Shell use by the hermit crab <i>Calcinus californiensis</i> at different levels of the intertidal zone

Abstract

The gastropod shell use of the hermit crab Calcinus californiensis was studied at Troncones, Guerrero, Mexico. Hermit crabs were captured at two different levels of the intertidal zone, in wave-protected and wave-exposed sites. C. californiensis occupied shells of 18 gastropod species. At both wave-action sites, Cantharus sanguinolentus was the most occupied shell. Columbella sp. was used more by females than by males, and Nerita scabricosta was more used by males. The frequency of use of the shells was different between the different wave sites. N. scabricosta and Columbella sp. were occupied more at the wave-protected than at the exposed sites; C. sanguinolentus and Stramonita biserialis were occupied more at the exposed sites. The hermit crabs at the wave-exposed sites occupied heavier and thicker shells compared with the crabs from the protected sites. The Olmstead-Tukey diagram showed eight shell species as dominant in the wave-protected sites, and seven in the wave-exposed sites. Ten shell species were rare in the wave-protected sites, and six in the wave-exposed sites. The rare shells occupied by the hermit crabs were relatively heavier than the dominant shells in both site types. Our results suggest that the shell weight is important in sites that are greatly affected by the hydrodynamics.