Increase trend of social hymenoptera (wasps and honeybees) in urban areas, inferred from moving‐out case by 119 rescue services in Seoul of South Korea

Abstract

AbstractThe number of social hymenoptera have decreased due to accelerated urbanization in Seoul, Korea, during the 1970s–1990s. However, recent changes in environmental conditions have brought distinct re‐growth of their colonies. In this study, we analyzed the re‐colonization trend of social hymenoptera in Seoul with moving‐out reports submitted to 119 rescue services from 2000 to 2009. A total of 14 253 social hymenoptera findings and treatment cases were reported during that time, and the reported numbers increased continuously every year. Among them, 87% of the cases were related to social wasps and 13% were for honeybees. Social wasps peaked from July to September, when the colonies matured, whereas honeybees peaked from April to July when colonies divided. As observed by geographical information system (GIS), moving‐out cases formed hotspots in low‐story buildings around green areas such as nearby forests or city green parks in Eunpyeong‐gu and Gwanak‐gu in Seoul. Among the social wasps, the most frequent species that caused a nuisance and direct stinging was Polistes rothneyi koreanus, the majority of which nested under eaves (63%). Among the honeybees, Apis mellifera was a nuisance while attaching to buildings and walls in the city (60%) during hive splitting. We present herein the situation of the return of social hymenoptera to Seoul and discuss the possible reasons for the recent increase in social wasps in urban areas, including enlarging the green space in urban areas and stable nesting places, which benefited colony development due to the relatively higher urban temperature and the few natural predators and parasitoids.