Discovery of a native host of Torymus beneficus (Hymenoptera: Torymidae), with description of a new Dryocosmus (Hymenoptera: Cynipidae)

Torymus beneficus Yasumatsu and Kamijo (Hymenoptera: Torymidae) is a native Japanese parasitoid of the chestnut gall wasp, Dryocosmus kuriphilus (Hymenoptera: Cynipidae). The known native host of T. beneficus is Andricus sp. (Hymenoptera: Cynipidae), but its entity has not been identified due to the lack of voucher specimens. During the field surveys of native host cynipids, we newly found leaf galls induced by a cynipid on Castanopsis cuspidata (Fagaceae). Morphological examination revealed that the cynipid was new to science. In this paper, we describe it as Dryocosmus murakamii Ide and Abe sp. nov. In addition, DNA analysis indicated that a Torymus species that had been reared from the galls induced by D. murakamii is identical to the early–spring strain of T. beneficus. We discuss significance of finding native host of T. beneficus.