Patterns of shell utilization and selection in two sympatric hermit crabs (Anomura: Diogenidae) in south-eastern Brazil

Abstract

The present study evaluated shell utilization and preference of two sympatric hermit crab species, Calcinus tibicen and Clibanarius antillensis, from Ilha Galheta de Dentro, Vitória Bay, south-eastern Brazil. Distribution of individuals and use and availability of shells were estimated in the field, where micro-habitat and shell partitioning were demonstrated between the two species of crabs. Calcinus occurred in higher numbers in the infralittoral fringe and shallow subtidal, while Clibanarius was found mainly in the midlittoral zone. The crabs used shells of different architectures and sizes. Calcinus used mainly globose and low spired shells (Tegula viridula and Cymatium parthenopeum), while Clibanarius utilized predominantly the elongated and high spired ones (mainly Cerithium atratum). Clibanarius used shells with smaller volume, weight, and aperture. Free access experiments were conducted in the laboratory and showed that Calcinus and Clibanarius had a high satisfaction rate, i.e. only 50% of the crabs exchanged their shells. From those that exchanged, they chose shells with higher internal volume than that used in the field, while shell weight did not present any increase. Clibanarius was found in shells closer to the preferred ones and in a very different proportion from shell availability, contrasting to Calcinus, which followed shell availability instead of their preferences. Shell internal volume was more important as a choice factor than the weight for both hermit crab species, showing that crabs optimized shell volume in relation to shell weight in the free access experiments.

Characterization of the occupied shells by the hermit crab Clibanarius vittatus (Decapoda, Diogenidae) at Baixio Mirim tideflat, Guaratuba Bay, southern Brazil

“…Secondly, the occupation of a specific shell is influenced either by the interactions among hermit crabs, such as intra-specific competition for the shell, or by other resources (Bertness 1980, Gherardi and Nardone 1997, Dominciano and Mantelatto 2004, Sant'Anna et al 2006b), coexistence of different hermit crabs species (Kellog 1977, Bertness 1980, Gherardi and Nardone 834 SARA R. SAMPAIO and SETUKO MASUNARI 1997, Floeter et al 2000, Turra 2003, Sant'Anna et al 2006b), predation (Bertness 1982, Rotjan et al 2004), presence of gastropods in the community (Bertness 1980, Turra and Leite 2001, Sant'Anna et al 2006a, previous experience (Hazlett 1993, Hahn 1998, Meireles et al 2008, Alcaraz and Kruesi 2009) and formation of aggregations (Hazlett 1981, Turra andLeite 2000a). The hermit crab ability in detecting odours of died or dying gastropods was also reported (Kratt andRittschof 1991, Chiussi et al 2001).…”

“…Among these characteristics are weight (Hahn 1998, Dominciano and Mantelatto 2004, Turra and Leite 2004, size (Bertini andFransozo 2000, Turra andLeite 2004), opening size (Botelho and Costa 2000, Bertini and Fransozo 2000, Sant'Anna et al 2006a) and architecture and volume (Gherardi and Nardone 1997, Floeter et al 2000, Shih and Mok 2000.…”

Shell occupation by the land hermit crab Coenobita violascens (Anomura, Coenobitidae) from Phuket Island, Thailand

“…Quantitative shell characters were measured and examined, including shell length (SL) and width (SW), weight (WW), internal volume (SIV), aperture length (SAL) and width (SAW). The internal volume of shells was evaluated using a graduated syringe (Floeter et al, 2000). All quantitative measurements were recorded to the nearest 0.01 mm for size using digital vernier calipers, 0.01 g for weight using digital weighing scales, and 0.1 ml volume using graduated syringes.…”

The molding hypothesis: linking shell use with hermit crab growth, morphology, and shell-species selection

“…The variability in shell use by hermit crabs is thought to be influenced by environmental factors such as shell availability (Bertness 1980, Leite et al 1998), but crab preferences may also be important (Floeter et al 2000, Turra & Leite 2002. Previous studies have demonstrated that past experience of hermit crabs with shells may lead to shell-related behavioral plasticity.…”