Blue-winged Olives
Baetis
Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.
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This is the first of it's family I've seen, collected from a tiny, fishless stream in the Cascades. The three species of this genus all live in the Northwest and are predators that primarily eat stonefly nymphs Merritt R.W., Cummins, K.W., and Berg, M.B. (2019).
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Stonefly Genus Suwallia (Sallflies)
Only Suwallia pallidula is known to be commonly encountered on trout streams.
Genus Range
Specimens of the Stonefly Genus Suwallia
2 Female Adults
I didn't key this one out under the microscope, but I just keyed a similar one from Montana and this one matches the macroscopic appearance closely enough that I'm guessing it's the same thing.
I collected a few of these throughout the afternoon. The positive ID on the adults allowed me to also put a species ID on the nymphs.
2 Adults
A large number of photos from the microscope allowed a fairly confident ID on this one, which not coincidentally matches very well a previous specimen of Suwallia pallidula that I collected in Washington.
2 Nymphs
This specimen keys out to Suwallia, for which I did not find any nymph species keys. However, I'm placing it in Suwallia pallidula because I caught a few adults in the same spot that closely resembled the abundant nymphs and keyed them out to species. Features I noted under the microscope when keying this specimen to genus included apical hairs of cercal segments that were directed at posterior angles, and the longest apical hairs of distal segments were shorter than their following segment.
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References
- Merritt R.W., Cummins, K.W., and Berg, M.B. 2019. An Introduction to the Aquatic Insects of North America (Fifth Edition). Kendall/Hunt Publishing Company.
Stonefly Genus Suwallia (Sallflies)
Taxonomy
Species in Suwallia
Suwallia forcipataForceps Sallflies
0
0
Suwallia pallidulaLittle Yellow Stoneflies
5
35
Species in Suwallia: Suwallia forcipata, Suwallia pallidula
6 species (Suwallia autumna, Suwallia dubia, Suwallia lineosa, Suwallia marginata, Suwallia sierra, and Suwallia wardi) aren't included.