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Baetis fuscatus (Pale Watery)

Nymphs of this species typically live in the riffle areas of rivers and streams either on in-stream vegetation or amongst the sand and gravel on the bed.  The nymphs swim in short, darting bursts swims amongst the substrate, or climb amongst the vegetation.  They feed by scraping algae from submerged stones and other structures, or by gathering or collecting fine particulate organic detritus from the sediment. 

 

There is generally one generation per year that overwinters in the egg stage, with adults present between May and October.  Some workers have suggested that there may be two or more generations per year.

 


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Emergence of the adults probably takes place at the surface of the water during daylight hours.  The males of this species swarm at dusk, but may also swarm at other times of the day.

 

Once mated, the female flies to the river and lands on a partly submerged stone.  She then folds her wings and pulls herself under the water to find a suitable place to lay her 1200 eggs.  The eggs are laid individually alongside each other to form a contiguous patch of eggs.  Once completed, she will sometimes climb back out of the water and fly away, however more often than not, she will be swept away by the current.

 

Due to the problems with the identification of nymphs, it is difficult to compile a complete distribution for this species.  Baetis fuscatus is however, thought to be less common than Baetis scambus.