Landscape effects on insect community composition and disease spread in an agroecosystem

Insect vector community composition across large spatial scales is a critical and understudied driver of disease spread, and studies on this subject could lead to a predictive framework for optimizing disease control. The landscape species pool hypothesis postulates that landscape-wide biodiversity moderates alpha biodiversity; complex landscapes may directly affect vector species diversity by altering host plant availability. Indeed, increasing landscape complexity consistently increases vector natural enemy abundance and diversity in agroecosystems, which may also have cascading effects on vector abundance and behavior. However, landscape effects on vector populations and disease spread remain largely theoretical. In our research, we test the effects of landscape complexity on the vector and vector natural enemy community composition, and disease spread in an agroecosystem. Results from the summer of 2012 demonstrate that increasing the landscape complexity within 0.5km radius of a field decreased disease prevalence, while there was no effect of landscape complexity within a 5km radius. There was high species richness across the region; during the 2012 season, at least nine species of vector natural enemies were trapped, as well as more than 57 vector species, only three of which were colonizing species on the disease host. We will discuss the effect of landscape complexity on the insect community and disease prevalence, as well as the importance of non-colonizing species for disease transmission.