ALTERED BEHAVIOR OF PARASITIZED KILLIFISH INCREASES SUSCEPTIBILITY TOPREDATION BY BIRD FINAL HOSTS

Parasites that are transmitted from prey to predator are often associa ted with altered prey behavior. Although many concur that behavior mod ification is a parasite strategy that facilitates transmission by maki ng parasitized prey easier for predators to capture, there is little e vidence from field experiments. We observed that conspicuous behaviors exhibited by killifish (Fundulus parvipinnis) were associated with pa rasitism by larval trematodes. A field experiment indicated that paras itized fish were substantially more susceptible to predation by final host birds. These results support the behavior-modification hypothesis and emphasize the importance of parasites for predator-prey interacti ons.