Behavior of Parasitized Aposematic Caterpillars: Advantageous to the Parasitoid or the Host?

Smith Trail (1980) suggested that this system (Euphydryas phaeton caterpillars and their parasitoids) is appropriate for testing the hypothesis of host suicide, and that parasitized hosts advertise themselves to predators and, thus, contribute to increased survivorship of their nonparasitized siblings. However, it appears from this study, other life-history information cited on this system, and data cited on the E. editha-parasitoid system that host suicide is unlikely in such nymphalid butterflies. Rather, these observations support the hypothesis that the behavior of parasitized larvae prior to parasitoid emergence may increase the parasitoids' chances of escaping predation and parasitism. Consequently, behavior of parasitized hosts in host-parasitoid systems may contribute to higher survivorship of parasitoids just as the behavior of hosts parasitized by true parasites promotes acquisition by definitive hosts and, thus, parasite survival.