Thrips of the British Isles

Distributions

The British and Irish distributions noted here are based on the detailed county records given in the 1976 Royal Entomology Society's Handbook (Mound et al., 1976), supplemented by a survey of more recent depositions of specimens in the Thysanoptera collection of the Natural History Museum, London, and the personal, published and unpublished, collecting records of the authors. Records from Ireland are summarised by O'Connor (2008). Few people have collected thrips in Britain, and the county records were derived largely from the activities of R. S. Bagnall or Guy Morison during the first half of the 20th century. Morison lived in Aberdeen for much of his life, a fact reflected in the many records of thrips from northern Scotland, but during the 1939-1945 war, his official duties took him widely across Britain. The distribution records are thus not necessarily a good reflection of the actual distribution of species, particularly as some may be based on single wind-dispersed individuals. Furthermore, populations of many species of thrips appear to be strongly aggregated and non-random at a local scale, making accurate sampling of local faunas difficult. The overall biomass of Britain's insect fauna has almost certainly decreased in recent decades (e.g., Hayhow et al. 2016), analogous to a recently quantified decline observed from a number of nature reserves in Germany (Hallmann et al., 2017), but the available data is not suitable for analysing any decrease in thrips populations. However, for fungus-feeding Phlaeothripidae, records and personal experience indicate that these were more readily collected up into the 1960s and 1970s than in the first decades of the present century. Concerning distribution across these islands, it appears that more thrips species have been found in the drier eastern areas than in the moister western areas. Interpreting distributions along the north/south axis is more difficult, because it appears that many species can be dispersed from south to north by winds at least during the summer. Distribution records quoted here for continental Europe are provided as large-scale summations derived mainly from cross-referencing zur Strassen (2003), Fauna Europaea (Vierbergen, 2013) and, where available, a number of published national or regional check-lists such as Gertsson (2015).