Atração de Paguros criniticornis Dana, 1852 (Decapoda, Anomura, Paguridae) para eventos de predação simulada

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

Hermit crabs are decapods crustaceans that occupy empty gastropod shells to obtain protection against predators and desiccation. They must periodically obtain new shells because of crab growth and deterioration of shells. New shells are obtained by chance encounter of an empty shell, by shell exchange with another hermit crab, and by attending gastropod predation events. In these events, the flesh of dead or dying gastropods liberates organic chemical substances signaling to hermit crabs the possibility of obtaining new shells. Pagurus criniticornis attraction by simulated gastropod predation was studied in laboratory and field experiments with the objective of testing two hypotheses: (1) individuals in shells of low adequacy, poorer conditions and more damaged would be more attracted to simulated predation events and (2) that hermit crabs would not be equa11y attracted to predation events containing different types of baits (e.g. there would be a specificity in the response to particular chemical signals). Pagurus criniticornis is a hermit crab common to the intertidal and shallow sub tidal zone of the Araçá region, São Sebastião, SP and uses main1y shells of the gastropod Cerithium atratum in this local. Collected hermit crabs were measured, weighed, identified in relation to sex and evaluated in relation to the adequacy and condition of their shells. The size and weight of the hermit crabs, the weight, condition and the adequacy index ("SAI") of its shells were compared between attracted and non-attracted individuals of the population. Males and females differed in their selection of shells. Attracted hermit crabs were the same size and weight as the population on average, but occupied lighter shells. As a result, these crabs displayed smaller values of SAI, showing that they occupied inadequate, smaller shells than ideal. In addition, the shells occupied by attracted hermit crabs had more physical damage and higher levels of encrustation by epibionts than average. Hermit crabs were mainly attracted to bait of crushed gastropods when compared with conspecific and bivalve ones representing indirect evidence that exists specificity of the attraction sign. The results of this study show that hermit crabs attracted to gastropod predation events occupy non-ideal and more damaged shells and that these events represent for them the opportunity to change their shells for a better one

ASSUNTO(S)

ecologia - são sebastião (sp) aspectos ambientais

ACESSO AO ARTIGO

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