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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Stonefly Family Nemouridae (Forestflies)
Where & when
Time of year : Late winter to mid-spring
In 357 records from GBIF, adults of this family have mostly been collected during April (27%), May (22%), March (15%), June (15%), July (8%), and February (6%).
In 120 records from GBIF, this family has been collected at elevations ranging from 20 to 11135 ft, with an average (median) of 6070 ft.
Family Range
Specimens of the Stonefly Family Nemouridae
1 Male Adult
This is the smallest stonefly I've ever collected, with a body only 5.5 mm long.
Although not in-focus in my pictures, its first tarsal segment is similar in length to the third, while the second is much shorter. This helps with family-level identification.
Examining this specimen under a microscope shows a membranous lobe on the dorsal base of the cerci, which is the key characteristic in Merritt & Cummins (4th ed.) to place the genus definitively as Malenka.
Following the species key in Jewett Jr's Stoneflies of the Pacific Northwest, the species appears to be Malenka tina. My dissecting microscope seems to show sternite 9 ending in a rounded knob, which distinguishes it from Malenka bifurcata, but the detail is hard to work out.
Also worth noting is that Montana appears to have this species, whereas birfucata is not know there: http://fieldguide.mt.gov/displaySpecies.aspx?family=Nemouridae
Although not in-focus in my pictures, its first tarsal segment is similar in length to the third, while the second is much shorter. This helps with family-level identification.
Examining this specimen under a microscope shows a membranous lobe on the dorsal base of the cerci, which is the key characteristic in Merritt & Cummins (4th ed.) to place the genus definitively as Malenka.
Following the species key in Jewett Jr's Stoneflies of the Pacific Northwest, the species appears to be Malenka tina. My dissecting microscope seems to show sternite 9 ending in a rounded knob, which distinguishes it from Malenka bifurcata, but the detail is hard to work out.
Also worth noting is that Montana appears to have this species, whereas birfucata is not know there: http://fieldguide.mt.gov/displaySpecies.aspx?family=Nemouridae
3 Female Adults
A few of these tiny stoneflies were among the only species of aquatic insect adults in the air on this particular afternoon, with most of the action coming from a species of Epeorus mayfly. I somehow forgot to photograph this one on the usual ruler, but I recall it was very, very small, with an abdomen no more than 1mm in girth and the body, not counting the wings, probably just 5-7mm long.
From N. Touchet River at Touchet Corral.
1 Adult
2 Nymphs
Nymphs of this species were fairly common in late-winter kick net samples from the upper Yakima River. Although I could not find a key to species of Zapada nymphs, a revision of the Nemouridae family by Baumann (1975) includes the following helpful sentence: "2 cervical gills on each side of midline, 1 arising inside and 1 outside of lateral cervical sclerites, usually single and elongate, sometimes constricted but with 3 or 4 branches arising beyond gill base in Zapada cinctipes." This specimen clearly has the branches and is within the range of that species.
Discussions of Nemouridae
deligon
2 replies
Posted by Deligon on Jan 15, 2010
Last reply on Jan 22, 2010 by Martinlf
FISHED THE HIWASSEE RIVER IN TENN , TODAY JAN 15 2010 WEATHER HIGH 50,S
AFTER A COUPLE OF WEEKS OF TEMPS IN THE TEENS, EXPECTED MIDGE HATCH,
WE HAVE A SHAD KILL WHICH I WANTED TO FISH STREAMERS HOPING TO TAG A BIG BROWN. BUT THE WINTER STONEFLY HATCH TOOK THE SHOW. DRY FLY FISHING IN JAN. WHAT IS THE LIFE CYCLE OF THESE FLIES? CAN THEY TOLERATE THE COLD NIGHT TEMPS? DO THEY EAT AND DRINK? WHOW DO THEY MATE?
THE MORE I LEARN THE MORE I DISCOVER I DON'T KNOW
DELIGON
AFTER A COUPLE OF WEEKS OF TEMPS IN THE TEENS, EXPECTED MIDGE HATCH,
WE HAVE A SHAD KILL WHICH I WANTED TO FISH STREAMERS HOPING TO TAG A BIG BROWN. BUT THE WINTER STONEFLY HATCH TOOK THE SHOW. DRY FLY FISHING IN JAN. WHAT IS THE LIFE CYCLE OF THESE FLIES? CAN THEY TOLERATE THE COLD NIGHT TEMPS? DO THEY EAT AND DRINK? WHOW DO THEY MATE?
THE MORE I LEARN THE MORE I DISCOVER I DON'T KNOW
DELIGON
Start a Discussion of Nemouridae
References
- Baumann, Richard W. 1975. Revision of the Stonefly Family Nemouridae (plecoptera) : a Study Of The World Fauna At The Generic Level. Smithsonian Contributions to Zoology undef(211): 1-74.
- Swisher, Doug and Carl Richards. 2000. Selective Trout. The Lyons Press.
Stonefly Family Nemouridae (Forestflies)
Taxonomy
6 genera (Lednia, Nanonemoura, Ostrocerca, Paranemoura, Shipsa, and Visoka) aren't included.