Linking local and landscape scale trophic interactions for plant-induced biological control of insect pests

Recruitment of parasitoids by herbivore-attacked plants through the emission of volatiles can provide an important stimulation of biological control in open field crops and thus to sustainable crop protection. Selecting crops that produce larger amounts of such volatiles may provide better pest control. However, as studies on this phenomenon are typically conducted in the laboratory or in small-scale field cages, it is unclear how these interactions unfold in realistic landscape settings where volatiles released by crops may be masked by volatiles released by natural vegetation. In addition, it remains to be identified at what spatial scales parasitoids respond to volatiles under field conditions. As a consequence, the potential of the selection of crop varieties for attracting natural enemies from surrounding habitats is unclear. This project aims to unravel how parasitoids respond to heterogeneous volatile mosaics produced by crop varieties with high and low volatile emissions, and wild plant species. Through an experimental approach at the plant, plot and landscape level, the functional spatial scale at which parasitoids respond to volatile mosaics will be assessed. Furthermore, through mechanistic individual-based models the relationships between the spatial distribution of crops and wild plant species, the emerging volatile mosaic and the response of parasitoids will further be explored. By using a combined experimental and modelling approach this project will provide important novel insights into the potential of the selection of crop varieties with elevated volatile emission for attracting parasitoids from surrounding habitats and the associated biological control.