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Baetis atrebatinus (Dark olive)

Baetis atrebatinus is a localised species with records from Hampshire and Dorset, Eire and the River Teifi in Wales.  Nymphs of this species typically live in the riffle areas of calcareous rivers and streams where they swim in short, darting bursts swims amongst the substrate.  They feed by scraping algae from submerged stones and other structures, or by gathering or collecting fine particulate organic detritus from the sediment. 

 

Very little is known about the lifecycle of B. atrebatinus, however adults have been collected between May and October, which may suggest that there is more than one generation per year.

 


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Emergence of the adults probably takes place at the surface of the, however very little is known about the swarming behaviour of this species other than that adults are found flying throughout the day and into the evening.

 

There have been no studies on the egg-laying habits of B. atrebatinus however it is likely that the female will lay around 1200 eggs either directly on a partly submerged stone or by releasing her eggs in several batches onto the water surface.