Distribution and abundance of the ivy bee, Colletes hederae Schmidt & Westrich, 1993, in Sussex, southern England

The solitary ivy bee Colletes hederae has recently naturally colonised the British Isles. It was first recorded in Britain in Dorset, near the south coast, in 2001. By 2021 it had reached Scotland and Ireland. It had spread to Sussex, some 100km east of Dorset by 2004, but occurred only locally. In autumn 2020, to determine the distribution and abundance of the ivy bee in Sussex, we made three surveys of 100 insects foraging on ivy flowers at 57 locations during the female flight period. We found the ivy bee at all 57. It was the second most abundant insect (22%), being outnumbered by social wasps (Vespula spp. 42%), but was more numerous than honey bees (Apis mellifera 14%). In autumn 2021 we made a further presence or absence survey at 17 additional locations, and the ivy bee was seen at each one. The results show that the ivy bee is now found throughout Sussex and is abundant. Comparisons of site characteristics showed no significant effect of urban versus rural locations on ivy bee relative abundance. It was, however, significantly more relatively abundant on Downland compared to Weald and Coastal Plain locations, and on chalk and sand derived soils compared to clay and alluvium derived soils. Possible reasons for the success of C. hederae in Britain are discussed.