This work covers the hydrophiloid beetles in five families, the Helophoridae, Georissidae, Hydrochidae, Spercheidae and the Hydrophilidae. One hundred and four species are reviewed, all of them being recorded from Britain, 70 with certainty from Ireland, 52 from the Isle of Man, and 63 from the Channel Isles. One hundred and one distribution maps are provided along with photographs of many sites.
This atlas is intended to be complementary to the atlas of predaceous water beetles or Hydradephaga already published. Both are rather more than just sets of distribution maps, with as much effort made to identify gaps in the knowledge as to discuss the basics of their identification, genetics, and biology.
Professor Frank Balfour-Browne, in his 1958 treatment of this group was obliged to admit that he had ultimately found these “palpicorns” as interesting, if not more so, than the better known Hydradephaga. His study of their distributions is extended here to cover the terrestrial species, mainly in Helophorus subgenus Empleurus and in the subfamily Sphaeridiinae of Hydrophilidae. The latter are largely associated with dung though many types of decaying material are fed upon by the adults, with their larvae being mainly predaceous in moist if not aquatic habitats.
The present recording scheme began in 1979, and over 149,000 records have been acquired through the activity of over 670 recorders, supported by the Biological Records Centre in Britain and the National Biodiversity Data Centre and CEDaR in Ireland.