Defining resistance and tolerance mechanisms against infections using the fruit fly as a model host

Hosts can use two basic mechanisms to defend themselves against infections. One is “resistance” in which the host reduces the number of parasites. Another is “tolerance” in which the host reduces the impact of the parasites on host fitness. We’ve found that in our model system – fruit flies infected with pathogenic bacteria – that both resistance and tolerance mechanisms are easy to find and play substantial roles in protecting the fly. We will discuss the range of tolerance mechanisms we expect to find in insects and how these mechanisms interact with resistance.