Capture of the oak ambrosia beetle within the host tree canopy

Abstract Because bark and ambrosia beetles fly during their dispersal and host location processes, their flight height is important for assessing their host selection strategy. There is no consensus regarding the height of their dispersal flight in forests, and their method of approaching trees is unclear. This is also the case for Platypus quercivorus (Murayama) (Coleoptera: Platypodinae), which causes Japanese oak wilt by transporting a pathogenic fungus. To clarify the vertical distribution of the flying population of P. quercivorus inside the host tree canopy, interception traps were set up at heights of 1–9 m from the ground near the main trunk of eight host trees, Quercus serrata Thunberg (Fagaceae). Captured beetles were collected between July and October 2022. Hole-boring activities were observed on all trees during the season, and beetles were captured at all heights from 1 to 9 m. Beetle capture probability increased with a decrease in height, and the number of captured beetles increased with a decrease in distance from the main trunk. However, the trap design in this study could not capture individuals coming directly above and must be addressed to elucidate their method of approaching their host plant.