Gallery diameter of ambrosia beetles (Coleoptera: Scolytidae, Platypodidae) and insect fauna in Quercus serrata (Fagales: Fagaceae) suffering from Japanese oak wilt

We dissected the trunk of a Quercus serrata Murray tree that had suffered from Japanese oak wilt, measured the gallery diameters of ambrosia beetles, and recorded the related insect fauna in the galleries of ambrosia beetles. In total, 545 individuals of nine species were captured from 494 galleries; these belonged to nine species [Cossoninae sp. (Curculionidae), Litargus japonicus Reitter (Mycetophagidae), Platypus calamus Blandford (Platypodidae), Platypus quercivorus (Murayama) (Platypodidae), Ambrosiodmus lewisi (Blandford) (Scolytidae), Ambrosiophilus atratus Eichhoff (Scolytidae), Xyleborus sp. (Scolytidae), Bitoma siccana Pascoe (Zopheridae), and Gempylodes ornamentalis (Reitter) (Zopheridae)]. The diameter of the gallery entrance on the surface of a debarked log may serve as a cue for species estimation of major ambrosia beetles in Q. serrata trees suffering from Japanese oak wilt in this study area. From the relationships between the body width and the gallery diameter, the distribution pattern within the tree, and the taxonomical analogy, a zopherid species, G. ornamentalis, was inferred as a possible predator and/or parasitoid of a causal agent in Japanese oak wilt, P. quercivorus.