Ephemera vulgata L., 1758 (Ephemeroptera, Ephemeridae) at Birlingham, Worcestershire on 6 April 2015
Paul F. Whitehead
Moor Leys, Little Comberton, Pershore, Worcestershire WR10 3EH.
The weather on 6 April 2015 was brilliantly sunny and settled. At about 12.45 hrs on the floodplain of the River Avon at Birlingham (SO9442 13 m a.s.l.) I observed a very large fully-developed male mayfly flying on a dead level course over the floodplain away from the river towards the Berwick Brook. The forward-projected forelegs and the long backward-projected abdominal setae or filaments produced a curious spectacle; I have watched male Ephemera sp. ‘dancing’ many times but never an example in direct continuous flight.
Especially notable in this instance was the colour of the abdomen which was a striking brick red apart from some limited darker dorsal markings. That too was something I had not observed before in regional Ephemera sp. and not a colour-form referred to by Macadam & Bennett (2010) although Kimmins (1950) does mention ‘reddish brown’ abdominal colour variation. According to Engblom (1996), Kimmins (1950) and Macadam & Bennett (2010) this example best fits Ephemera vulgata L., 1758. This is one of a group that prefers watercourses with soft sediment beds into which the larvae burrow (Engblom, 1996); a related species Ephemera danica (Müller, 1764) occurs widely in the English midland region. Upstream of Nafford Weir the river is somewhat ponded and it may be that these particular conditions favour E. vulgata. According to Mr G.H. Green (in litt., 19 April 2015) E. vulgata may occur more widely around the meander loops of the River Avon in Worcestershire but red forms seem not to have been observed up to now.
According to Kimmins (1950) and Macadam & Bennett (2010) the adult flight period of E. vulgata as from May to August so that an early April occurrence is unusual.
References
Engblom, E., 1996. Ephemeroptera, Mayflies, pp. 13-53 in Nilsson, A. (ed.), The aquatic insects of north Europe, a taxonomic handbook, volume 1. Apollo Books, Stenstrup.
Kimmins, D.E., 1950. Ephemeroptera. Handbooks for the identification of British insects 1(9). Royal Entomological Society of London.
Macadam, C. & Bennett, C., 2010. A pictorial guide to British Ephemeroptera. 132pp. Field Studies Council.