Best time of Year for Adult insect diversity

I was wondering what the best time of the year might be for adult insect diversity on the Yakima river. Are there any times of year that you guys find especially interesting? I ask this from a bug standpoint only, not from a fishing point of view.


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Hi Gary-

That is an interesting question, and one that I have never before attempted to answer. So, I quantified it by use of the emergence information for the Yakima River, which in my opinion is the most comprehensive emergence data available for the Yakima River. It lists the date range (by half months) for the following (24) insects (by common name) which are available to trout on the Yakima River, either as emergers, duns, spinners, or by virtue of falling into, or being blown into the water:

Bluewinged Olive
Brown Drake
Brown Dun
Golden Stone
Green Caddis
Green Drake
Little Brown Stone
Mahogany Dun
March Brown
October Caddis
Pale Evening Dun
Pale Morning Dun
Saddlecase Caddis
Shortwing Stone
Spotted Caddis
Yellow Quill
Yellow Sally

Based on my analysis of that data, and the following chart which I have produced from it, the answer to your question appears to be the 1st half of June, when a peak of (14) appear:

Hope this helps.
Thanks Roger! That is great information. I lead streamside field trips for freshman biology students at UW. We look for adult insects as well as turning over rocks and dipnetting to find nymphs in the water. Students work to classify insects by order and sketch some examples. Most of the students have seen very few insects and find the trip fascinating. This will be very helpful for timing field trips.

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