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Caenis macrura (Anglers' curse)

Caenis macrura has a widespread but localised distribution with the most northerly record from East Lothian.  The majority of records for this species are from the South East of England, however due to the problems with the identification of nymphs, it is difficult to compile a complete distribution for this species.  Caenis macrura is thought to be less common than C. luctuosa.  Nymphs of this species live in the pools and margins of rivers where they live in silt trapped between larger stones and gravel.  The nymphs are poor swimmers but are adapted for moving amongst the sediment.  They feed by collecting or gathering fine particulate organic detritus from the sediment. 

 

There is one generation a year, which usually overwinters as nymphs and emerges between May and August.

 


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Emergence of the adults typically takes place partially or entirely out of the water on a stick, stone or plant stem in the early morning.  The males of this species can be found swarming at dawn.  Once mated, the female flies upstream and descends to the surface of the water to release a few eggs by dipping the tip of her abdomen onto the water surface at intervals, or by actually settling on the surface for short periods.  After several visits to the water her supply of around 1200 eggs is finished and the spent female falls on to the surface.