Microhabitat characteristics affecting the occurrence and diversity of queen hornets (genus Vespa) in an urban green area

Urban parks and green areas are increasing globally. However, when hornets (genus Vespa) in particular among wild organisms adapt to and settle in urban green spaces, they are likely to come into conflict with humans. In this study in Cheonan city, South Korea, between April and June 2017, we used hornet traps to capture queen hornets that were awakening from hibernation, and identified the characteristics of these queen hornets. We selected three green types of urban areas, namely a natural-type neighborhood park, a children's park, and a remnant forest. We analyzed the simple regression between captured queen hornets and time over an eight-week period, as well as the relationship between captured queen hornets and microhabitat variables (including Normalized Difference Vegetation Index, canopy openness, elevation, land cover rate, and herbaceous plant cover rate), and green type. Over time, there was a significant increase in the number of Vespa ducalis and Vepsa analis that were late in awakening from hibernation. The number of captured queen hornets was significantly different in urban parks compared with in the remnant forest. However, V. ducalis was as frequently captured in the natural neighborhood park as were other queen hornet species. Some queen hornet species were significantly positively correlated with elevation (Vespa crabro, Vespa mandarinia, V. ducalis), herbaceous plant cover rate (all species of queen hornets), broad-leaved forest (all species of queen hornets), and artificially barren ground (all species of queen hornets) of microhabitat. Different species were affected differently by the microhabitat variables tested. Consequently, we recommend that when urban green spaces are created, design criteria for complex urban parks should aim at ensuring suitability for use by local residents, and for hornet conservation.