Vespula rufa (Linnaeus, 1758), known as the red wasp, is a social wasp species. We analyzed the complete mitochondrial genome of V. rufa from South Korea, for an ongoing systematic study of the Korean Vespidae. This species is distributed in northern parts of North America, northern and central Europe, and parts of Asia. It can be distinguished from other species of the genus by usually having reddish brown areas on the 1st and 2nd tergites. The mitogenome is 17,663 bp in length, includes 13 protein-coding genes, 24 transfer RNA genes, and two ribosomal RNA genes. The nucleotide composition is 40.5% adenines, 43.00% thymines, 6.1% guanines, and 10.4 % cytosines.

Hymenoptera is one of four largest orders of insects, with over 150,000 described species, 132 families, 27 superfamilies, and 2 suborders. There are currently about 3,000 hymenopteran species in 65 families and 20 superfamilies known in South Korea, of which the majority of the families have been studied while some of them are still poorly studied. The present overview on South Korean Hymenoptera aims to provide brief taxonomic history of the studies, a complete bibliography, a list of South Korean hymenopteran species, and information on South Korean hymenopterists for each taxon.

Social parasitism was occasionally found some Polistes species as well as Vespa species like Vespa dybowskii. In this summer, we newly discovered interspecific facultative parasitic relationship between two closely Polistes species, Polistes djakonovi and Polistes mandarinus, in a rural area of Machi-ri (N35°47′35.05″ E127°15′30.48″), Wanju-gun of Jeonbuk, South Korea. Individuals of P. djakonovi closely resemble individuals of P. mandarinus in their color pattern. Accordingly, the morphological similarity between two species should motivate the parasitism for the invader species. We obviously recognized case of typical social parasitism as follows. 1) P. mandarinus dwelling together in a nest of P. djakonovi, 2) A discovered yellow cocoon cap of P. mandarinus in the nest (cf. color of cocoon cap of P. djakonovi is white). Wecollected 2 females of P. mandarinus among all 30 individuals (14 females and 16 males) in the nest. However, we could not comprehend their ecological characteristics because this phenomenon was discovered after removing of this nest.

It was first recorded that Elasmus japonicus Ashmead had occurred from three Polistes nests in Busan city, Wanju-gun, and Pyeongchang-gun of South Korea. The 2 females and 14 males were collected from the nest of Polistes rothneyi koreanus in Busan city (N35°17′57.71″ E129°06′33.24″), 12 females and 2 males from P. djakonovi in Wanju-gun (N35°47′35.05″ E127°15′30.48″), 18 females and 3 males from P. snelleni in Pyeongchang-gun (N37°39′7.84″ E128°35′15.81″). P. rothneyi koreanus and P. djakonovi were first recorded as new hosts. To date, two Elasmus species, E. nephantidis and E. viridiceps, have been reported from South Korea. In this study, we provide diagnosis, description, and photos of female and photos of male of E. japonicus.

This study selected 10 species commonly emerging in Busan and Daegu showing distinct green structure distributions, and distribution differences were mapped and analyzed according to city of origin. As for G-IS (Green-Inhabiting Species) of both cities, there were six species, including V. mandarinia, V. ducalis, V. crabro flavofasciata, Vl. koreensis koreensis, Pa. indica, and P. snelleni, which mostly inhabited urban source green and satellite green structures. As for GU-IS (Green & Urban-Inhabiting Species), there were two species, V. simillima simillima and V. analis parallela, which nested at diverse sites and showed greater preference for green structures. On the other hand, U-IPS (Urban-Inhabiting Preference Species) consisted of two species, V. velutina nigrithorax and P. rothneyi koreanus, which nested at almost all sites, including urban and urban green areas, and were found to adapt well to an urban environment based on their far higher rate of urban nesting as compared to GU-IS species. In comparing emergence rates among the four urban GU-IS and U-IPS species in Busan and Daegu, regular distribution was mostly observed within the city of Busan, which is well equipped with a green network, whereas Daegu, which lacks green structure connectivity, showed its greatest distribution of species nearby urban green areas. Also this study shows that in Daegu with longer distance between green, U-IPS emerged up to far site beyond green areas as compared to Busan, which has short distances between green areas.

Invasive hornet Vespa velutina nigrithorax, which was found at Yeongdo, Busan for the first time in 2003, has been spreading to whole area of Gyeongnam and even to some southern parts of Gyeongbuk for last ten years, causing lots of damage. Urban area of Busan already showed dominant distribution of V. v. nigrithorax marking more than 90% of emergence rate by its spread, while in forest area, its rate had not been so high due to its competition with native Vespa species. However, recently dominance of this species was detected continuously in some forests in Busan. Thus, this study conducted a survey of emergence rate of V. v. nigrithorax at Mt. Bongraesan, Yeongdo-gu, Busan where it was discovered for the first time and also conducted observation of its behaviors related with competition for prey in order to understand its ecological niche relation with native Vespa species. Consequently, 4,560 individuals were collected in total out of main five species of Vespa at Mt. Bongraesan. Of these, V. mandarinia made up 8.7% with 397, V. crabro flavofasciata 21.2% with 965, V. analis parallela 23% with 1,048, V. simillima simillima 0.6% with 27, while V. v. nigrithorax made up 46.6% with 2,123, demonstrating the aspect of the most dominant emergence of V. v. nigrithorax. On the other hand, ecological niche due to competition for prey between V. v. nigrithorax and native Vespa species was revealed in the order of V. mandarinia >> V. crabro flavofasciata > V. analis parallela ≥ V. v. nigrithorax, telling ecological niche of V. v. nigrithorax was relatively low compared to native Vespa species, despite its dominant emergence. This background may explain why in forest area, V. v. nigrithorax had a limited spread and dominance compared to urban area of less competition among Vespa species. On the other hand, V. v. nigrithorax seems to have advantage in catching small insects due to developed agility with its smaller size than other Vespa species, and its rapid spread and adaptation in the local environment may be mainly attributable to its far more number of individuals than native Vespa species and consequent high reproductive rates and diversity of nesting site.