New host-parasitoid interactions in Naupactus cervinus (Coleoptera, Curculionidae) raise the question of Wolbachia horizontal transmission

Abstract

Naupactus cervinus is a weevil pest native to South America and distributed worldwide, with all populations infected with the endosymbiont Wolbachia pipientis. The study of this weevil’s natural parasitoids may help develop biological control strategies. We studied two parasitoids from adult females of N. cervinus in Argentina. DNA was extracted and the mtCOI gene was amplified and sequenced. We performed BLAST and family-level phylogenetic analyses by retrieving sequences of related genera from GenBank and BOLD databases. We compared COI genetic distances between our samples and putative congeneric species by pairwise comparisons to test if our identification at genus level was compatible in terms of genetic variability. BLAST analysis indicated that one of the parasitoids shared 88–92% sequence identity with several Tachinidae (order Diptera) and belonged to the genus Oestrophasia. This is the first report of a dipteran parasitoid for N. cervinus. The other parasitoid shared 82–88% sequence identity with several Braconidae (order Hymenoptera) and fell within the genus Microctonus with high nodal support. Genetic distance analyses revealed that both genera showed high-unidentified diversity, particularly among Microctonus species from Argentina, and that N. cervinus is parasitoidised by different species of Microctonus. Wolbachia infection was diagnosed through PCR and characterised by MLST genotyping. The microhymenopteran and N. cervinus most probably shared the wNau5 strain, which brought forward the question of parasitoids as vehicles for horizontal transfer. Further analyses on characterisation and geographic distribution of the infection at the population and community levels may shed light on a shared evolutionary history.