Minimizing bee bycatch in Japanese beetle traps

Pest trapping is a common practice when monitoring and managing harmful insect pests, but these traps can also attract non-target insects, or bycatch, such as bees (Hymenoptera: Apoidea). Bee bycatch has been noted in traps for pest Japanese beetles (JB, Coleoptera: Popillia japonica), which could harm important insect pollinators. We identified and quantified bee bycatch within the standard yellow-green JB traps throughout different regions of North Dakota. We also tested two trap alternatives at a site with high JB densities, i.e. an all-green trap and the standard yellow-green trap covered with metal mesh, with the goal being to maintain the number of JB trapped while decreasing the incidence of bee bycatch. We expected that: 1) geographic region will impact the identity of bees in JB traps, 2) bycatch will increase along with the size of the urban area being surveyed, 3) large bees will make up a greater proportion of bycatch than small bees, 4) trap alternatives will catch equivalent densities of JB and lower densities of bees compared to the standard trap. Results from the state survey are forthcoming. With the alternative trap testing. The standard control traps (Green & Yellow) caught significantly more JB than the two alternative traps. In addition, control traps also caught more bees than the two alternative traps and were the only traps that caught bumble bees. However, the overall level of bee bycatch was low, possibly because of the extremely high densities of JB.