Mechanisms of host exploitation by a microsporidian parasite

Parasites exploit their hosts to enhance their growth and reproduction, yet the mechanisms underlying host manipulation remain understudied for many taxa. The microsporidian Vavraia culicis, a potential biological control agent for mosquitoes, serves as an excellent model to explore such mechanisms. In this study, we investigate how infection by V. culicis lines that vary in virulence alters resource dynamics within the mosquito host Anopheles gambiae. Using metallomics and quantification of protein, carbohydrate, and lipid content, we show that infection alters host resource concentrations in ways that depend on parasite virulence. More virulent parasites led to increased protein levels and greater energy demands, evidenced by higher carbohydrate reserves. Additionally, infection with V. culicis impacted host metal content, particularly zinc and manganese, used by V. culicis independently of its evolutionary background. Iron availability, a key nutrient for parasite growth, enhanced spore production, with selected parasite lines better able to exploit host iron than unselected. These findings provide insight into the mechanisms by which V. culicis manipulates host resources, shedding light on the role of host exploitation in parasite virulence and the potential use of microsporidia as biological control agents in vector biology.