In the 20th century, models of host-parasitoid systems were a major force in the development of theory for population dynamics. However, the start of the new millennium saw a major upswing in models of the dynamics of host-pathogen and host-parasite interactions. In this talk, I will compare host-parasitoid and host-pathogen modeling approaches in the literature, in order to illuminate the differences in the approaches taken, and the ecological questions asked, in models of these two types of resource-consumer interactions. I will ask what disease ecology can learn from host-parasitoid theory, or alternatively, whether host-parasitoid theory should be revised in the light of recent developments in host-pathogen modeling.
Results/Conclusions
Several of the major concepts of host-pathogen theory -- the basic reproduction rate (R0), thresholds for pathogen invasion or persistence, and pathogen fade-out – are virtually absent from the host-parasitoid literature. This is perhaps because many of the early host-pathogen models were motivated by diseases of humans (in which the total host population size is assumed to be constant). In contract, because the hosts in many host-parasitoid models were pest insects with the potential for explosive population growth rates, host-parasitoid models instead often focused on the search for factors that can lead to low densities of the host and a stable host-parasitoid equilibrium. Because parasitoids can display a fascinating range of behaviors, much host-parasitoid theory concentrated on the implications of these behaviors for population dynamics, while generally ignoring the host immune response and within-host dynamics (which are important components of recent developments in host-pathogen modeling).