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Mayfly Species Drunella spinifera (Western Slate Olive Dun)

Pictures Below
This taxon prefers cold water and does not flourish where water temperatures exceed 60 degrees. As with the slightly larger Drunella coloradensis, this species prefers cold tailwaters, high elevation headwaters and spring creeks.  

Where & When


Region: West

Time Of Year (?): August and September

This species is most prevalent near the Pacific Coast, but scattered local populations occur throughout the northern states of the West.

Spinner Behavior


Time Of Day: Dusk

These spinner flights are too sparse to be important.


Pictures of 4 Western Slate Olive Dun Specimens:

Specimen Page:12
Male Drunella spinifera (Western Slate Olive Dun) Western Slate Olive Dun NymphMale Drunella spinifera (Western Slate Olive Dun) Mayfly Nymph View 8 PicturesIn a bucket full of Drunella coloradensis nymphs, this was the only specimen of Drunella spinifera (and the first one I've found anywhere).
Collected July 28, 2019 from Mystery Creek #199 in Washington
Added to Troutnut.com by Troutnut on July 30, 2019
Drunella spinifera (Western Slate Olive Dun) Western Slate Olive Dun NymphDrunella spinifera (Western Slate Olive Dun) Mayfly Nymph View 3 PicturesThis species resembles Drunella grandis but the spines tell the story.
Collected December 19, 2009 from 6 mile Creek in Montana
Added to Troutnut.com by Bnewell on June 26, 2011
Specimen Page:12

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