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Ameletus inopinatus (Eaton), 1887
Identification Elliott, Humpesch and Macan (1988) for nymphs: Elliott and Humpesch (1983) for adults.
Distribution There are British Records from xxxxxxxxx. A. inopinatus occurs in pockets throughout Europe.
Habitat and ecology Nymphs are found in the calmer reaches of small rivers or brooks between stones and boulders. They have also been recorded from stony lochs in the Scotland. They are usually confirmed to higher altitudes, between 400 and 1800 metres. There is one generation a year which overwinters in the larval stage and emerges between late May and August. By August specimens are usually much smaller. The nymphs usually, but not necessarily always emerge via stones or vegetation during daylight hours. Males swarm above the water in the afternoon only. Sladecek (1973) in Elliott, Humpesch and Macan (1988) lists A. inopinatus as an indicator of xeno-saprobity, occurring in waters without organic enrichment. Elliott, Humpesch and Macan (1988) classify A. inopinatus as a 'collector-gather', meaning it feeds by filtering or gathering fine particulate organic detritus from the sediment. The nymphs usually swim in short bursts, interspersed with periods of clinging to submerged plants and stones.
Status Known from xxxxxxxxxxxxxxxxxxxxxx. The last specimen was recorded in 19xx.
Threats Development may increase the risk of organic enrichment and other forms of pollution. River bed disturbance such as during river engineering work can also be detrimental by increasing the silt load of the water for a period. This can clog the gills of invertebrates or, where it settles, bury them. This threatens a broad spectrum of aquatic life, not specifically Ephemeroptera. Removal of the marginal vegetation in which the adults of A. inopinatus emerge and possible shelter is likely to lessen the chances of successful breeding.
Conservation In addition to avoiding the above threats, the possible importance of marginal and river bank vegetation should not be overlooked. This is likely to provide emergence sites and shelter for the adult stages. Maintenance work liable to damage this component should be carried out only on one bank, and preferably on only short stretches of, say 50 metres in each 200 metres in any one year.
Author C.R. Macadam
References
Bratton, J.H. (1990). A review of the scarcer Ephemertoptera and Plecoptera of Great Britain. Research and survey in nature conservation No. 29, 39pp.
Elliot, J.M., Humpesch, U.H. and Macan, T.T. (1988). Larvae of the British Ephemeroptera: A key with ecological notes. Scientific Publications of the Freshwater Biological Association No. 49, 145pp.
Elliot, J.M. and Humpesch, U.H. (1983). A Key to the Adults of the British Ephemeroptera. Scientific Publications of the Freshwater Biological Association No. 47, 101pp.
Goddard, J. (1991). Trout flies of Britain and Europe - The natural fly and its matching artificial. A. & C. Black, London, 242pp.