Most species of Megastigmus are considered important economic pests that grow in seeds, especially of conifers. Accurate identification of species is a crucial step for the biological research of parasitic pests and the further application of biological control. However, their large variety, small size, similar morphology and different growth and development stages have brought great challenges to taxonomic research. Traditional morphological identification often takes a long time and this requires us to seek a new method for rapid and accurate identification. Therefore, the better identification of Megastigmus urgently needs to be combined with molecular methods to help taxonomic development.
Here, Megastigmus daduheensis sp. n. (Chalcidoidea: Megastigmidae) was identified, based on morphology and molecular markers, such as COI and Cytb. M. daduheensis sp. n. is distinct from other known species of the same genus in the morphology. The results of the molecular phylogenetic tree, similarity alignment and genetic distance indicate that the COI and Cytb sequences of M. daduheensis sp. n. are highly similar to M. sobinae and M. duclouxiana, but there are some genetic differences. The genetic distances of M. daduheensis sp. nov. with M. duclouxiana and M. sabinae were 0.34 and 0.33 and the percentages of shared base pairs were 76.3% and 76.8%, respectively. Both morphological and molecular data classified M. daduheensis sp. n. as a new species. The obtained COI and Cytb sequences of M. daduheensis sp. n. can be used as DNA barcodes, providing molecular data for rapid and accurate identification of this species in the future.