Evolutionary ecology of an obligate and behaviorally manipulating insect- pathogenic fungus, Entomophthora muscae

Abstract

Some insect-pathogenic fungi have evolved the ability to behaviorally manipulate their insect hosts. This has required the fungi to develop intricate mechanisms of infection, proliferation, and behavioral hijacking, which has led to speculation that behaviorally manipulating fungi must only infect a narrow range of hosts. One well-known example is the insect-pathogenic fungus Entomophthora muscae, which infects dipterans. Here, we present the different stages of the life cycle of E. muscae, focusing on the unique adaptations that allows the fungus to enter and proliferate inside its hosts, the possible ways it manipulates behavior, how the fungus exits the killed host to seek new susceptible hosts, and the ecological implications of these adaptations for determining the host range and intra-specific variation of E. muscae. We address the biology of E. muscae from an evolutionary ecology perspective and discuss the capacity of the fungus for behavioral manipulation within an extended phenotype framework. We highlight areas where further research is needed to fully develop E. muscae as a model system for host-pathogen research, for example to address questions relating to fitness consequences of an infection.