A review of the scarce and threatened Coleoptera of Great Britain. Part 3: Water beetles
Garth N. Foster
Three hundred and eleven taxa were assessed for this review of water beetles of Great Britain.


Jäch & Balke (2008) estimate that there are currently about 18,000 species of water beetle of which 70% have been described. About thirty families have aquatic representatives, with 25 of them having at least half of them aquatic. The estimates for the dominant families are, from October 2005, Dytiscidae with 3,908 species, 5,000 being estimated, Hydraenidae (1,380/2,500), Hydrophilidae (1,800/2,320), Elmidae (1,330/1,850), Scirtidae (900/1,700) and Gyrinidae (750/1,000). The Palaearctic (3,350 named as opposed to 3,900 estimated), the Neotropical (2,510/3,900) and the Afrotropical (2,700/3,750) regions have the most species, followed by the Oriental (2,200/3,580) and the Australasian (1,300/2,100), the Nearctic (1,420/1,550) being by far the poorest in terms of diversity.
The first step is to identify what is included in the term “water beetle” for the purposes of this review. Many species of beetle are obligately associated with water with a continuum from those that are found throughout their life-cycle under water (reed beetles in the genus Macroplea and a few weevils), through the majority, i.e. those that pupate out of the water but are aquatic as both larvae and adults, and on to those that live in the water as larvae but are found above and away from the water as adults. The latter include the Scirtidae, many plant-feeding species, in particularly most of the reed beetles or Donaciinae. The current review is concerned with the Hydradephaga (that is the aquatic members of the suborder Adephaga, the Gyrinidae, Haliplidae, Noteridae, Paelobiidae and Dytiscidae), with our sole representative of the suborder Myxophaga (Sphaerius acaroides), and with several families of Polyphaga (the Hydrochidae, Helophoridae, Georissidae, Spercheidae, the aquatic Hydrophilidae, Hydraenidae, Heteroceridae, Dryopidae, Elmidae, Psephenidae, Limnichidae and the Scirtidae).

The status of leaf beetles and weevils will not be considered further here, being best addressed for these as part of an overall review of Chrysomeloidea and Curculionoidea. Further, the many moisture-loving ground and rove beetles should also be reviewed as part of their major phylogenetic groups. There will always be inconsistencies in combining the ecological and phylogenetic approaches, but the groups covered here have the virtue of being part covered by a single national recording scheme. Another peculiar exception is the exotic and largely aquatic family Ptilodactylidae, represented in Britain by a species confined to moist soils in greenhouses (Mann 2006). 


Three hundred and eleven taxa were assessed for this Review, four of them regarded as subspecies (Nebrioporus depressus depressus and N. depressus elegans, and Ochthebius viridis viridis and O. viridis fallaciosus), the rest as species.


The area covered in this Review is Great Britain (i.e. England, Scotland and Wales, excluding the Isle of Man and the Channel Isles). Northern Ireland and the Republic of Ireland have produced a joint Red List of water beetles for the whole of Ireland (Foster, Nelson & O Connor 2009).



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Soft back, A4, 142pp.
ISSN 1473-0154
Please cite as: Garth N. Foster, (2010), A review of the scarce and threatened Coleoptera of Great Britain. Part 3: Water beetles, Soft back, A4, 142pp., ISSN 1473-0154