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 Calineuria (Golden Stones)
The only species in this important western genus is Calineuria californica. See its species hatch page for more information.
Genus Range
Identification
To determine whether a specimen of Perlidae belongs to Calineuria, use the Key to Genera of Perlidae Nymphs.
Specimens of the Stonefly Genus Calineuria
1 Male Adult
A few of these larger stoneflies were fluttering around the South Fork on an evening dominated by much smaller species.
This one has been difficult to identify. I can't spot any of the gill remnants characteristic of Perlidae, but the wing venation seems to point in that direction. I tried keying it out as Perlodidae but arrived at Isoperla, every western species of which has significantly smaller bodies than this one.
Edit: See forum comments for a likely correct identification.
This one has been difficult to identify. I can't spot any of the gill remnants characteristic of Perlidae, but the wing venation seems to point in that direction. I tried keying it out as Perlodidae but arrived at Isoperla, every western species of which has significantly smaller bodies than this one.
Edit: See forum comments for a likely correct identification.
2 Female Adults
I caught this female in the vegetation on a trail about 50 feet above the stream. The coloration on its head differs from that of a male I collected recently on a nearby river, and from another female I collected on the same river. But it still keys out confidently to Calineuria, and californica is the only species of that genus in the area.
3 Nymphs
This striking golden stonefly is the first of its species I've had the chance to photograph.
This is a difficult one. It keys convincingly to either Calineuria or Doroneuria. There is no mesal longitudinal row of silky hairs on thorax and abdominal dorsum, in either my pictures or anything I can see up close under the microscope. Lacking those hairs should indicate Calineuria. But abdominal sternum 7 has an incomplete posterior setal fringe, which would indicate Doroneuria, although the key says "usually" on that characteristic. For now I'm going with Calineuria, but it's far from certain. Maybe it's a younger Doroneuria and they don't grow that row of hairs until they're older. The markings on the head, especially the shape of the bright spot around the posterior ocelli, match online images of Calineuria californica better than Doroneuria.
1 Streamside Picture of Calineuria Stoneflies:
This Calineuria californica female was captured and placed in "bug jail," but was released when I saw it was loaded with eggs and about to drop them, and I could tell it was the same specis (albeit different gender) I photographed a few days ago.
In this picture: Stonefly Species Calineuria californica (Golden Stone).
Start a Discussion of Calineuria
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 Calineuria (Golden Stones)
Taxonomy
Species in Calineuria
Calineuria californicaWestern Stoneflies
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Species in Calineuria: Calineuria californica