An electrophoretic and morphological study of three Ecdyonurus species (Ephemeroptera: Heptageniidae) occurring in the British Isles

Abstract The objective was to investigate the validity of three closely-related British species: Ecdyonurus dispar, E. venosus and E. torrentis . The species were characterized by eleven enzyme-substrates and fifteen different enzyme-loci, comparisons being made not only between species but also between five populations of E.dispar (three from Britain, one from France, one from Switzerland), two populations of E.venosus and two populations of E. torrentis (one from Britain, one from Switzerland for both species).
Four monomorph enzyme-loci (aldolase, mannose phosphate isomerase, arginine phosphokinase, glutamate-oxaloacetate transaminase-2) exhibited interspecific differences in their mobilities and therefore validated the conclusion that E. dispar, E. venosus and E. torrentis are distinct species. There were no monomorph enzyme-loci that were different between populations of the same species. There were, however, some intraspecific differences revealed by the presence of polymorphic enzyme-loci: seven in E.dispar (retinol dehydrogenase, hexokinase-1 and 2, glutamate-oxaloacetate transaminase-!, malate dehydrogenase-1, phospho-glucomutase, indophenol oxidase-2), three in E. venosus (glutamate-oxaloacetate transaminase-1, malate dehydrogenase-1, phospho-glucomutase) and three in E. torrentis (hexokinase-1, glutamate-oxaloacetate transaminase-1, malate dehydrogenase-1).
The morphological characters of larvae and adults were examined and some were used in new keys to larvae and adults.