Use of molecular identification techniques for the study of parasitoids of the chestnut gall wasp

The chestnut gall wasp Dryocosmus kuriphilus Yasumatsu (Hymenoptera, Cynipidae) is considered as a major pest of Castanea species worldwide. A three-year monitoring of the indigenous parasitoids of this pest was performed by collecting specimens inside the galls. Each specimen was processed by molecular analysis. DNA was analysed by amplification and sequencing of the COI gene, coding for cytochrome c oxydase subunit 1. Each sequence was compared with reference sequences from adults sampled in Sardinia and those present both in GenBank and Barcode of Life Database (BOLD). This procedure enabled us to identify all immature life stages, included larvae and pupae that cannot be identified otherwise. The identified species belong to 7 genera of the superfamily Chalcidoidea : Eupelmus (Eupelmidae) , Eurytoma and Sycophila (Eurytomidae) , Ormyrus (Ormyridae), Mesopolobus (Pteromalidae), Megastigmus and Torymus (Torymidae) . Among the identified taxa we found a few unknown species and also some sibling ones. These findings will make it possible to elucidate the relationships between the indigenous parasitoids and the host pest and to verify the spreading of the introduced exotic antagonist Torymus sinensis in order to plan new control strategies.