Modeling abundance and risk impact of Vespa velutina nigrithorax (Hymenoptera: Vespidae) in Korea: application of a species abundance model.

The Asian yellow-legged hornet, Vespa velutina nigrithorax, is native to Southeast Asia. However, it has invaded many countries in temperate regions, causing serious threats to honeybees and human health. With a growing demand for estimating the potential distribution of this species, multiple studies have resorted to occurrence-based models. However, they are less informative for predicting local abundance patterns associated with the species' impact. Thus, we aimed to develop an abundance-based distribution model for V. v. nigrithorax in Korea to support the forecast of its impact and associated management strategies. The abundance data of V. v. nigrithorax were collected from 254 sites for 4 years covering the country and used to develop a model with bioclimatic and land composition variables. Along with the abundance model, the classical occurrence model was tested to determine whether it could provide a reasonable prediction on the estimation of local abundance. As a result, the abundance model provided higher discriminative power and accuracy than the occurrence model to evaluate the impacts caused by V. v. nigrithorax. On the other hand, the occurrence model was not able to discriminate abundance in the areas occupied by V. v. nigrithorax, indicating an unclear occurrence-abundance relationship or oversimplification of the estimated niche created by the occurrence model. Based on the final abundance model, risk indices for human health and honeybee losses were suggested. These results could help to provide support for risk management of V. v. nigrithorax in Korea and to give biological information to other countries where this species has already become established or which it is likely to invade in the near future.