Shell Exchange in Hawaiian Hermit Crabs

Shell exchange behavior of intertidal Hawaiian hermit crabs was observed in the laboratory. Outcomes of 255 shell-related interactions were analyzed to test the predictive powers of two models of resource exchange. In the case of intraspecific interactions, the negotiations model (which predicts that exchanges should occur only when both crabs will gain in shell value) was superior to an aggression model of resource exchange. In the case of interspecific interactions, the negotiations model accurately predicted outcome of CalcinusCalcinus interactions, but poorly predicted outcome of Calcinus-Clibanarius interactions