Entomopathogenic fungi infecting non-pest insects: Implications for ecosystem services and relevance of behavioural ecology

Entomopathogenic fungi infect a wide array of insects from most orders and they are among the natural enemies that contribute to the regulation of insect populations. However, only a limited number of studies have focused on the impact of fungal pathogens on populations of non-pest insects. Effects of entomopathogenic fungi on non-pest host populations should receive more attention based on the increasing interest in conservation biological control. In this strategy, founded on competition theory, non-pest host populations adjacent to cropping systems will in principle affect pest populations through shared natural enemies. We present examples of selected non-pest host-fungus systems from temperate ecosystems that are relevant for the expected ecosystem service provided by entomopathogenic fungi. Predators are among the non-pest hosts that are infected by fungi. Recent advances in our understanding of the effect of pathogens on the behaviour of predators may shed light on the significance of entomopathogenic fungi for the regulation of predator populations. We discuss what we can learn about host-pathogen interactions from behavioural ecology and which life history parameters in the host that may be important for the impacts of fungal pathogens on their host populations