Lack of Host Species Selection by the Exotic Parasitic Crustacean,Argulus japonicus

Abstract

Abstract We tested the hypothesis that Argulus japonicus, an external parasite of fishes, would prefer goldfish (Carassius auratus), a cyprinid with which it evolved, to the fathead minnow (Pimephales promelas), a common cyprinid native to North America. In each of two experiments, parasites were confined individually with goldfish and fathead minnows, and attachments to each fish were recorded. The frequencies of attachment were not significantly different from random, regardless of whether expected frequencies were adjusted to reflect the relative surface areas of the two host species. Moreover, once attached to a host, an Argulus was not more likely to detach from either host species within the first thirty seconds of attachment.