PHENOLOGY OF SOCIAL WASPS (HYMENOPTERA: VESPINAE) IN THE KUJAWY REGION (NORTHERN POLAND) UNDER THE INFLUENCE OF CLIMATIC CHANGES 1981–2000

Duration of flight periods were determined for most numerous species of social wasps for two decades 1981–1990 and 1991–2000. The tendency to shorten the duration of wasps’ flight periods by 12–18% was observed during 1990s. An attempt was undertaken to associate this phenomenon with observed climatic changes that shape nutritional resources of Vespinae.