Host thermal biology: the key to understanding host-pathogen interactions and microbial pest control?

1 The role of pathogens in insect population dynamics remains poorly understood and their performance in biological control is erratic. Here we identify that temperature and host thermal behaviour, both the active interaction with environmental temperature and solar radiation via thermoregulation and the passive interception of these factors by thermal generalists, are central to understanding host–pathogen interactions. 2 We demonstrate that pathogenicity, the latent period of infection and host recovery rate can all vary dramatically across and between seasons due to thermal biology of the host and changes in environmental temperature. 3 Such effects have not been thoroughly explored in any previous investigations but may have major implications for disease dynamics in insects and possibly in ectotherms in general, and for development of effective biopesticides.