Thermal biology in insect-parasite interactions

Recently, several applied studies exploring the use of pathogens for insect biocontrol have demonstrated significant effects of environmental temperature on the outcome of infection. For example, host resistance, host recovery, pathogen virulence and replication can alter considerably with sometimes very small changes in temperature. Moreover, the effectiveness of certain insect parasitoids and the activity of endosymbionts can vary across the range of realistic temperatures experienced in the field. These responses are not necessarily linear or immediately predictable, because they derive from a complex ‘genotype-by-genotype-by-environment’ interaction. Given the importance of parameters such as virulence and resistance in determining the course of a host–parasite interaction, such effects of temperature could have profound implications for host–parasite dynamics and coevolution.