Species Focus - Small Red Damselfly (Ceriagrion tenellum)

This pretty damselfly, with its weak flight, is only ~30mm long and some 15% smaller than its more robust cousin the Large Red Damselfly (Pyrrhosoma nymphula). It is readily distinguished from it by having reddish instead of entirely black legs. Also, the males (see photo) carry no black abdominal markings in comparison to the larger species. Like many coenagrionid damsel species, the females come in several colour forms with variable amounts of black along the top of the abdominal segments. In the common typica form abdominal segments 4 to 8 are so coloured (see photo) but in smaller numbers there is also a totally red form like the male and a melanistic form with all the segments black. The adults are on the wing here from late May through to early September with peak times in June to August.

This is Western Europe’s only member of the coenagrionid genus Ceriagrion. It comprises roughly 50 species of small- to medium-sized damselflies across sub-tropical and tropical regions of Africa, Asia and Australia. The males are characteristically brightly coloured in shades of yellow, red, orange and even green. In the eastern Mediterranean our species is replaced by a very closely related species, the Turkish Red Damsel (Ceriagrion georgifreyi).

Unlike its virtually ubiquitous larger cousin, the Small Red has a distinctly southern and western European and also British distribution. It extends into North Wales along the coastal fringe of Merionethshire and Caernarvonshire, particularly along the Llŷn Peninsula, reaching as far north as northern Anglesey (see maps). It can be found at heights up to 200m but is generally absent from sites close to sea level due to human interference. In 2012, I found a strong colony in a heathland pond only 300m from the sea at Amlwch Port (see map). This is probably its most northern occurrence in Europe and, until its discovery there, the species was thought to be extinct in Anglesey. Colonies seem to have been lost at sites around Newborough due to conifer afforestation.

The Small Red is largely confined to acidic sphagnum bog pools, mires or the shallow fringes of larger lakes in heathland habitats (see photo). Such sites include the iconic Llyn Tecwyn Isaf in Merionethshire. It is usually associated with the growth of the Marsh St John’s Wort Hypericum elodes which provides evidence of its possible presence. It also breeds at base-rich mires such as at Cors Geirch NNR that traverses the Llŷn Peninsula.

If you see a Small Red in North Wales please submit your records, preferably with photographs, to the Cofnod ORS or the LERC Wales App.