Molecular and morphological variation among the European species of the genus Aphidius Nees (Hymenoptera: Braconidae: Aphidiinae)

The main objective of the present paper was to analyse and compare the patterns of molecular and morphological divergence of European parasitoid wasps belonging to the diverse genus Aphidius Nees, 1818. The maximum likelihood and maximum parsimony trees constructed by including 64 different haplotypes of the barcoding region of mitochondrial cytochrome oxidase subunit I (mtCOI) identified for 33 Aphidius species showed identical topology. A high level (99%) of bootstrap support was found for the phylogenetic line consisting of A. ribis Haliday, 1834, A. chaetosiphonis Tomanovic & Petrovic, 2011 and A. hortensis Marshall, 1896, and for the group consisting of A. colemani Vierck, 1912, A. transcaspicus Telenga, 1958, A. asteris Haliday, 1834 and A. platensis Brethes, 1913. The remaining lineages on the trees were not significantly supported. We applied the approach of geometric morphometrics to explore morphological divergences in forewing size. A significant difference of mean wing shape was found between Aphidius species. The observed low resolution of the mtCOI gene of morphologically and ecologically well-defined Aphidius species is probably due to species hybridisation followed by introgression of mtDNA. Despite low resolution of the phylogenetic tree, the permutation test for a phylogenetic signal in wing shape was statistically significant, indicating that phylogenetically more closely related species are more similar than unrelated ones. A clear agreement between molecular and morphological variation was determined only for the two phylogenetically well-resolved groups.