Species identification and genetic differentiation of European cavity-nesting wasps (Hymenoptera: Vespidae, Pompilidae, Crabronidae) inferred from DNA barcoding data.

Solitary trap-nesting wasps are prospective bioindicators of anthropogenic pressures on natural ecosystems and one of the surrogate taxa for biodiversity assessments. The implementation of these studies is taxonomy-based and relies on accurate identification of species. The identification of larval stages of cavity-nesting Hymenoptera, collected using trap-nests, is complicated or impossible before the post-hibernation hatching of adults. DNA barcoding may allow the identification of the trap-nesting Hymenoptera species immediately after collection of the trap-nests, using larvae or dead specimens as sources of DNA. Using the standard barcoding sequence, we identified 33 wasp species from the families Vespidae, Pompilidae and Crabronidae, inhabiting trap-nests in Europe. Within-species and between-species genetic distances were estimated to evaluate the differences of intraspecific and interspecific genetic diversity. Genetic distances between related species indicated an obvious "barcoding gap". Neighbour-joining analysis revealed that groups corresponding to taxa of genus level are cohesive as well. COI barcode approach was confirmed as a valuable tool for taxonomy-based biodiversity studies of the trap-nesting Hymenoptera.