Impairment of feeding behavior of the spottail shiner (Notropis hudsonius) by metacercariae of the digenetic trematode Diplostomum flexicaudum.

Abstract

The spottail shiner (Notropis hudsonius) was infected in the laboratory with cercariae of the eye fluke Diplostomum flexicaudum to determine if infection by the parasite impaired feeding behavior of the fish. The mean and s.d. number of metacercariae in each eye was 6.7 +-6 for control fish and 124 +-47.6 for fish with a high metacercarial load. Control fish attacked food much more often that fish with a high parasite load (mean +- s.d. of 6.5 +-1 and 1+-1 trials out of seven, respectively). Although the mean reaction distance of control fish was 2.6 times farther away than for fish with high metacercarial load, the difference was not statistically significant. It is proposed that decreased feeding ability could weaken the second imtermediate fish host and contribute to increased predator success by the bird definitive host.