Molecular species delimitation of the Asian chestnut gall wasp biocontrol agent released in Italy

Abstract

Molecular species recognition and identification, based on the mitochondrial cox1 and on the nuclear ITS2, were performed on individuals of Torymus sinensis collected in Italy, on its close relative T. beneficus and on native torymids. The automatic-gap-discovery (ABGD) analyses correctly separate almost all morphospecies. On the basis of cox1, individuals of late-spring T. beneficus clustered with T. sinensis, and those identified as early-spring T. beneficus were recognized as a separate entity. Whereas, T. beneficus ecotypes clustered with T. sinensis on the basis of ITS2. Coalescent tree-based methods confirmed these results. The cox1-based recognition of early-spring T. beneficus as a separate phylospecies led us to conclude that this taxon deserves to be treated as a valid species, whereas individuals identified as late-spring T. beneficus might be considered as part of T. sinensis. Morphological identification and BLAST analyses confirmed that no T. beneficus was imported into Italy to control Dryocosmus kuriphilus.