Social wasps (Vespinae) in urban gardens and woods

Global change, including urbanization, affects species ecology. Social wasps (Vespinae) are ubiquitous in urban areas, which increases their encounters with humans. We studied social wasps in urban gardens and nearby urban woods in central Finland, using beer traps. Social wasps were common in gardens and woods, and overall wasp abundance was higher in the woods. Also, the most abundant and frequent species Vespula vulgaris was more abundant in the woods than in the gardens. Variation in the overall abundance and the abundance of V. vulgaris was great among trap locations, which likely results from wasps’ social nesting habits. Neither the abundance of all social wasps nor that of V. vulgaris differed between July and August. Our study suggests that urban woods might increase wasp abundance in adjacent gardens. Vespula germanica — a species expanding its range northwards in Finland — was documented for the first time from central Finland. The ongoing global change is likely to change wasp communities and their encounters with humans in urban environments.