Discrimination of Torymus sinensis Kamijo (Hymenoptera: Torymidae) and T. beneficus Yasumatsu et Kamijo and their hybrids by allele-specific PCR

Abstract

Torymus sinensis and Torymus beneficus (Hymenoptera: Torymidae) are, respectively, introduced and indigenous parasitoid wasps that attack the invasive chestnut gall wasp, Dryocosmus kuriphilus (Hymenoptera: Cynipidae) in Japan. Torymus beneficus has two emergence types in spring, here designated early-spring and late-spring. It is very difficult to distinguish these Torymus species and emergence types of T. beneficus by their morphological and ecological characteristics. We designed four allele-specific primers for the internal transcribed spacer 1 region of nuclear ribosomal DNA, and developed three kinds of allele-specific PCR. These methods enabled us to distinguish the species, emergence type, and F₁s. This is the first report of the use of molecular markers to distinguish T. sinensis, the late-spring strain of T. beneficus, and their F₁s.