Effects of supplemental food and habitat structural complexity on generalist predatory mites inhabiting grapevine

Abstract: Generalist predators can exploit resources at different trophic levels, and may prey on other arthropods that are also natural enemies (i.e., intraguild predation, IGP) to persist on plant in absence of prey. The availability of trophic supplements outside the IGP modules and habitat structural complexity can have implications on the outcome of IGP in predator’s population dynamics. The effect of increased habitat structural complexity created by domatia and the provision of supplemental food constituted by the plant-pathogenic fungi Grape Powdery Mildew (GPM) was tested on two predatory mites [Amblyseius andersoni (Chant.) and Typhlodromus pyri Scheuten] inhabiting grapevine. Predatory mites’ population abundance and persistence were promoted by access to domatia. The availability of GPM promoted the persistence of predatory mites and mitigated the negative effect of absent domatia on T. pyri. The coexistence of the two predatory mites was favoured by the access to domatia and GPM availability but at a low population level of the intraguild prey.Extended abstract