41st Annual Meeting of the Society for Invertebrate Pathology
and 9th International Conference on Bacillus thuringiensis

The factors affecting the evolutionary ecology and dynamics of the interaction of Bt (Bacillus thuringiensis) with its lepidopteran host, the diamondback moth (DBM) will be discussed. The evolution of host resistance to Bt threatens the sustainable use of this bacteria to modern agriculture and our understanding of this host-pathogen interaction provides a fantastic system in which to explore ideas about the evolutionary ecology of pathogen virulence, pathogen transmission and host resistance. We will focus on three aspects of our research from within-host to field dynamics. First, from a detailed study of the within-host mechanisms of infection, we will discuss how the presence of alternative (non-toxin) genes (or Bt-related bacteria that express these non-toxin genes) are essential to Bt infectivity and transmission. Second, selection experiments have revealed how DBM resistance evolves in relation to Bt strain diversity and host population density and this work will be considered in conjunction with evolutionary theory on pathogen virulence and host resistance. Finally, from field experiments, we will illustrate how the diversity and population structure of native Bt floras (and related bacteria) are affected by the presence of pest insects (e.g., DBM) and/or Bt-based insecticides (e.g., DiPel).