Wrong landing on a non‐host occurs under the canopy of a host: The presumed path of the ambrosia beetle Platypus quercivorus to approach its host

Abstract

Abstract The ambrosia beetle Platypus quercivorus is a vector of a pathogenic fungus that causes Japanese oak wilt. Its host is Fagaceae trees; however, these beetles also erroneously bore into unsuitable, non‐host tree species, which can be affected by neighbouring host tree species and the size of the non‐host. We attached sticky sheets to the host and non‐host tree species of P. quercivorus and counted the number of beetles that landed weekly, in a season of beetle dispersal. We quantified the density of the host canopy above, the basal area of surrounding hosts and the diameter at breast height (DBH) of each non‐host tree. The host canopy density affected the probability of beetles landing on non‐hosts, and the host basal area and non‐host DBH affected the number of beetles landing on non‐hosts. Thus, P. quercivorus is probably initially attracted to a dense host canopy, secondly attracted to the high density of the host and thereafter aggregate onto thick trees, including non‐host species. The number of beetles landing on the surrounding host also affected beetle landing on the non‐hosts, suggesting that landing on non‐hosts is an error that occurs in high frequency during the seasons when many beetles land on the hosts.