Evolution versus co-evolution: An example from stage-structured host-parasitoid systems

Understanding the coevolution of host resistance and parasite virulence, and its consequences for host-parasite ecological dynamics remains an area of active research.  In this talk, we present a stage-structured mathematical model of host-parasitoid interaction, motivated in part by our experimental populations of Plodia interpunctella and its solitary parasitic wasp Venturia canescens. Using a trait frequency approach, we first model the evolution of host resistance and parasitoid virulence as independent and separate processes.  This framework is then extended to permit coevolutionary dynamics.  We highlight the qualitative strategic differences that arise from coevolution versus evolutionary processes.  For example, we find that coevolution reverses the predicted host resistance strategies and promotes parasite persistence.  We also present a new resistant host strategy in the presence of virulent parasites.  In addition, we will discuss current and future work on the affects of environment variability in terms of theoretical and empirical studies.