Predation on gastropods by shell-breaking crabs: effects on shell availability to hermit crabs

Abstract

This study addressed the effect predation on gastropods by shell-breaking crabs has on shell availability to hermit crabs.(1) Variable rates of predation on the gastropod Cerithium atratum were recorded within and among the crab species Menippe nodifrons, Panopeus occidentalis, Eriphia gonagra, and Callinectes danae. Predation rate was more dependent on crab size than on crab species, and all predators consumed the largest individuals of C. atratum available. nodifrons generally crushed its prey, C. danae and E. gonagra used both peeling and crushing, and P. occidentalis generally peeled. Crushing was usually lethal, while peeling attempts resulted in higher prey survival. Predatory strategy was dependent on relative prey size: small shells were crushed, medium-sized were peeled, and large ones were nondestructively preyed upon through the aperture. (5) Most shells used by the hermit crab Pagurus criniticornis (68%) in nature presented damage very similar to that recorded for gastropods preyed upon experimentally, indicating that this kind of predation makes new shells available to hermit crabs. (6) M. nodifrons showed a clear preference for the gastropod C. atratum over the hermit crab P. criniticornis, suggesting differential predation pressures in nature. In conclusion, shell availability to hermit crabs was demonstrated to be dependent on predator species and size, gastropod architectural defenses, and on the relative predator-prey size, which determined the predatory strategy and the damage inflicted on the shells.

Experimental predatory behavior of the stone crab Eriphia verrucosa (Forskål, 1775) (Decapoda, Brachyura, Eriphiidae)

“…Crabs are highly mobile and are known to have an important role in structuring assemblages on rocky shores worldwide (Behrens Yamada and Boulding, 1996;Rilov and Schiel, 2006;Silva et al, 2008;Forsstrom et al, 2015). They are predators of intertidal hard-shelled prey such as limpets, mussels, gastropods and sea urchins (Turra et al, 2005;Silva et al, 2010;Laitano et al 2013). When they feed on these hard-shelled preys, many crabs are capable of extracting the meat by peeling the shell aperture and thus avoid spending more time and energy in shell crushing (Rossi and Parisi, 1973).…”

Epibiont occurrence on gastropod shells used by the hermit crab Loxopagurus loxochelis (Anomura: Diogenidae) on the northern coast of São Paulo, Brazil

“…parasitism) may leave the shells intact, while predation may completely destroy them (see TURRA et al 2005 (BERTNESS & CUNNINGHAM 1981, MCLEAN 1983, LAU 1987) that allow their future use by hermit crabs (TURRA et al 2005).…”

“…In view of the gap that exists in the Brazilian literature regarding studies on the epibiont fauna that occurs on the surface of shelter gastropod shells used by hermits -among the few studies from shallow/intertidal waters are those of CREED (2000) and TURRA (2003) -and the state of preservation of shells (TURRA 2003, TURRA et al 2005, we studied the external gastropod shell coverage (by invertebrates), comparing the presence and types of epibionts on the shells that are most frequently used by the endemic Southern Atlantic hermit crab Loxopagurus loxochelis (Moreira, 1901). We also evaluated the conditions of conservation of shells used by this species.…”

Habitat heterogeneity in the assemblages and shell use by the most abundant hermit crabs (Anomura: Diogenidae and Paguridae): does the occupied shell species differ according to gender and species?

“…Shells of O. urceus possessed a smaller aperture than the other gastropod shells. During intra or inter-specific fighting for the shell or predator attack, hermit crabs are removed from their shells through the aperture (Turra et al, 2005). Therefore, a smaller aperture hinders their removal and provides greater protection (Bertini and Fransozo, 2000).…”