Gilchrist, M.A.*; Sasaki, A.: Host-Parasite Coevolution based on Models of Within-Host Dynamics

Host-Parasite coevolution has long been an area of interest of evolutionary biologists. However, most mathematical models on the evolution of parasite virulence view the host as a static, non-evolving entity. By focusing on the dynamics of the parasite population within a host and by coupling these dynamics with a simple model of the host’s immune response, we are able to simultaneously explore the evolutionary dynamics of both the host and the parasite. Our findings indicate that there is a single evolutionary stable equilibrium towards which the system evolves. Furthermore, the impact of the disease on host survivorship and parasite fitness at the equilibrim is a function of its location which in turn is a function of the cost of the host’s immune response and the amount of damage caused by each unit of parasite growth.