The effect of neighbor identify on biocontrol agent (Galerucella spp.) choice in visitation, oviposition, and feeding on purple loosestrife (Lythrum salicaria)

Biological control of Lythrum salicaria began in North America more than 20 years ago. Shortly after the introduction of the first biocontrol agents (Galerucella pusilla and Galerucella calmariensis) the program was largely considered to be a success. Since their introduction, researchers have investigated biotic and abiotic factors impacting establishment, dispersal potential, and the role of aggregation pheromones on beetle population dynamics. To date, the impact plant neighborhood on beetle dispersal and establishment remains largely unknown. In this study we investigated the effect of target plant neighbor identify on dispersal, oviposition, and feeding preference. Plants in clusters with lower diversity contained more beetles, eggs, and had more damaged leaves than plants in the most diverse treatments. Understanding the effect of plant neighborhood on beetle preference for visitation, oviposition, and feeding could help to more effectively implement biocontrol releases as a part of landscape scale IPM programs for invasive species.