Interactions between woodpecker attack and parasitism by introduced parasitoids of the emerald ash borer

This study examines the relationship between native woodpecker predation and parasitism by the introduced parasitoids S. agrili and T. planipennisi. We established a cohort of parasitized larvae on select ash trees and then used screening to exclude woodpeckers from some sections of the tree. We show that while woodpeckers had no effect on observed parasitism rates of individual trees, the presence of parasitized larvae changed woodpecker foraging behavior and resulted in significantly lower overall foraging by woodpeckers. We hypothesize these changes are due to these larval parasitoids being a lower quality food reward. Parasitism of EAB larvae could contribute to a decrease in patch quality for woodpeckers such that they would quit foraging sooner than expected if it were a high-quality, un-parasitized patch. This study fills a gap in our understanding of the complex relationship between woodpecker mortality and parasitism mortality of EAB and our results demonstrate that this relationship may have broad implications for the EAB biological control program. Graphical abstract
Source: Biological Control - Category: Biology Source Type: research