The effects of allelochemical transfer on the dynamics of hosts, parasitoids, and competing hyperparasitoids

Abstract

Allelochemicals produced by plants may be ingested by herbivorous insects and transferred to higher trophic levels with potentially deleterious effects. We develop a system of differential equations to investigate the effect of the transfer of allelochemicals, such as nicotine, on the population dynamics of a system of hosts, parasitoids, and two competing hyperparasitoids that attack different life stages of the parasitoids. We find both somewhat deleterious effects of nicotine on the larvae‐attacking hyperparasitoids and increased attack rates for the pupae‐attacking hyperparasitoids can promote coexistence. We also use an evolutionary game‐theoretic approach to determine the optimal distribution of hyperparasitoid attacks among nicotine‐producing and nicotine‐free plants. With strong deleterious effects of nicotine and increased attack rates for the pupae‐attacking hyperparasitoid, we find both species attack parasitoids on the nicotine‐free plant but only pupae‐attacking hyperparasitoids attack parasitoids on the nicotine‐producing plant.