Salmonflies
Pteronarcys californica
The giant Salmonflies of the Western mountains are legendary for their proclivity to elicit consistent dry-fly action and ferocious strikes.
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It's only barely visible in one of my pictures, but I confirmed under the microscope that this one has a prosternal horn and the antennae are mid-way between the eyes and front of the head capsule.
I'm calling this one Pycnopsyche, but it's a bit perplexing. It seems to key definitively to at least Couplet 8 of the Key to Genera of Limnephilidae Larvae. That narrows it down to three genera, and the case seems wrong for the other two. The case looks right for Pycnopsyche, and it fits one of the key characteristics: "Abdominal sternum II without chloride epithelium and abdominal segment IX with only single seta on each side of dorsal sclerite." However, the characteristic "metanotal sa1 sclerites not fused, although often contiguous" does not seem to fit well. Those sclerites sure look fused to me, although I can make out a thin groove in the touching halves in the anterior half under the microscope. Perhaps this is a regional variation.
The only species of Pycnopsyche documented in Washington state is Pycnopsyche guttifera, and the colors and markings around the head of this specimen seem to match very well a specimen of that species from Massachusetts on Bugguide. So I am placing it in that species for now.
Whatever species this is, I photographed another specimen of seemingly the same species from the same spot a couple months later.
I'm calling this one Pycnopsyche, but it's a bit perplexing. It seems to key definitively to at least Couplet 8 of the Key to Genera of Limnephilidae Larvae. That narrows it down to three genera, and the case seems wrong for the other two. The case looks right for Pycnopsyche, and it fits one of the key characteristics: "Abdominal sternum II without chloride epithelium and abdominal segment IX with only single seta on each side of dorsal sclerite." However, the characteristic "metanotal sa1 sclerites not fused, although often contiguous" does not seem to fit well. Those sclerites sure look fused to me, although I can make out a thin groove in the touching halves in the anterior half under the microscope. Perhaps this is a regional variation.
The only species of Pycnopsyche documented in Washington state is Pycnopsyche guttifera, and the colors and markings around the head of this specimen seem to match very well a specimen of that species from Massachusetts on Bugguide. So I am placing it in that species for now.
Whatever species this is, I photographed another specimen of seemingly the same species from the same spot a couple months later.
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Mayfly Genus Attenella
This genus is represented by several important species across the country. In the East, Attenella attenuata (Little Blue-winged Olive) has garnered much attention as an important hatch in past angling texts. However, possible confusion with more abundant Drunella species of Blue-winged Olives has perhaps led to overstatement regarding its importance.
The species Attenella margarita (Little Western Blue-winged Olive) is disributed nationally. Though its eastern presence is relatively minor, in the West this mayfly can produce exceptional hatches.
Two other western species, Attenella delantala and to a lesser extent Attenella soquele often show up quite prominently in stream samples taken in the coastal states. The dramatically marked delantala nymph cannot be easily confused with any other western ephemerellid. Information regarding their winged appearance seems to be unavailable for now. Why they have gone unreported in angling texts is a mystery perhaps due to emergence behavior or misidentification by anglers of the dun and spinner stages. There is much to learn about these species that can be fairly abundant in some locales.
The species Attenella margarita (Little Western Blue-winged Olive) is disributed nationally. Though its eastern presence is relatively minor, in the West this mayfly can produce exceptional hatches.
Two other western species, Attenella delantala and to a lesser extent Attenella soquele often show up quite prominently in stream samples taken in the coastal states. The dramatically marked delantala nymph cannot be easily confused with any other western ephemerellid. Information regarding their winged appearance seems to be unavailable for now. Why they have gone unreported in angling texts is a mystery perhaps due to emergence behavior or misidentification by anglers of the dun and spinner stages. There is much to learn about these species that can be fairly abundant in some locales.
Genus Range
Hatching behavior
A significant difference between this genus and other ephemerellids is it's reported propensity to emerge from its nymphal shuck from the stream bottom in heptagenid fashion. While other ephemerellids can and do emerge underwater, this usually takes place within a foot at most from the surface. Attenella's availability as a submerged dun in the entire water column means use of the winged wetfly or soft hackles fished deeply can be an important tactic.Specimens of the Mayfly Genus Attenella
1 Male Dun
This specimen came from the same hatch as a female.
3 Female Duns
I found this dun unusually late in the year for anything in the Ephemerellidae family in the East. It's also small for that family.
This specimen came from the same hatch as a male.
This dun was badly damaged in transport and all its legs fell off, but I photographed it anyway because I wasn't sure I would fine more and it's an interesting species. Luckily I collected better specimens a few days later.
3 Nymphs
Notes from the microscope on the ID: Maxillary palp is present, distinctly 2-segmented, but very small. Gills on segment 4-7. This specimen has some unfortunate damage to the abdomen, but it's the only one I found in my sample.
Start a Discussion of Attenella
References
- Knopp, Malcolm and Robert Cormier. 1997. Mayflies: An Angler's Study of Trout Water Ephemeroptera . The Lyons Press.
Mayfly Genus Attenella
Taxonomy
Species in Attenella
Attenella attenuataSmall Eastern Blue-Winged Olives
3
11
Attenella delantalaLittle Blue-Winged Olives
2
15
Attenella margaritaLittle Western Blue-Winged Olives
2
13
1 species (Attenella soquele) isn't included.