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 specimen resembled several others of around the same size and perhaps the same species, which were pretty common in my February sample from the upper Yakima. Unfortunately, I misplaced the specimen before I could get it under a microscope for a definitive ID.
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Mayfly Genus Caenis (Angler's Curses)
When the important hatches of Tricorythodes were first discovered by anglers, Caenis was given the credit. We now know that the Caenis mayflies are a different group, smaller and less common in trout streams, and they hatch in the evening instead of the morning.
They very rarely elicit selective feeding, but when they do they're very tough to match because they're often much smaller than size 28. This difficulty has earned them the nickname "Angler's Curse."
They very rarely elicit selective feeding, but when they do they're very tough to match because they're often much smaller than size 28. This difficulty has earned them the nickname "Angler's Curse."
Where & when
Most Caenis mayflies emerge in the evenings when other, larger mayflies are abundant on the water. This limits their importance.
In 320 records from GBIF, adults of this genus have mostly been collected during July (28%), June (26%), August (24%), May (10%), and September (8%).
In 145 records from GBIF, this genus has been collected at elevations ranging from 26 to 8022 ft, with an average (median) of 2690 ft.
Genus Range
Hatching behavior
Caenis mayflies typically emerge, molt into spinners, mate, and oviposit within one hour.Nymph biology
Substrate: Silt, weeds
Specimens of the Mayfly Genus Caenis
1 Female Dun
1 Female Spinner
9 Nymphs
This interesting little Caenis nymph is way darker than any of the others I collected in January 2004, probably a different species. It also has shorter tails.
I confirmed the identity of this nymph by looking at it under a microscope to be certain of the shape of its gills and head.
I confirmed the identity of this nymph by looking at it under a microscope to be certain of the shape of its gills and head.
I confirmed the identity of this nymph by looking at it under a microscope to be certain of the shape of its gills and head.
I confirmed the identity of this nymph by looking at it under a microscope to be certain of the shape of its gills and head.
This is probably the most common lake mayfly in western Montana. It can be found with one or more species of Caenis.
Start a Discussion of Caenis
References
- Arbona, Fred Jr. 1989. Mayflies, the Angler, and the Trout. Nick Lyons Books.
- Caucci, Al and Nastasi, Bob. 2004. Hatches II. The Lyons Press.
- Knopp, Malcolm and Robert Cormier. 1997. Mayflies: An Angler's Study of Trout Water Ephemeroptera . The Lyons Press.
- Leonard, Justin W. and Fannie A. Leonard. 1962. Mayflies of Michigan Trout Streams. Cranbrook Institute of Science.
- Schwiebert, Ernest G. 1955. Matching the Hatch. MacMillan Publishing Company.
Mayfly Genus Caenis (Angler's Curses)
Taxonomy
Species in Caenis
Caenis amicaGray-Winged Blue Duns
0
0
Caenis anceps
0
0
Caenis diminuta
0
0
Caenis eglinensis
0
0
Caenis hilaris
0
0
Caenis latipennisGray-Winged Sulphur Duns
0
0
Caenis punctata
0
0
Caenis tardata
0
0
Caenis youngi
1
2
Species in Caenis: Caenis amica, Caenis anceps, Caenis diminuta, Caenis eglinensis, Caenis hilaris, Caenis latipennis, Caenis punctata, Caenis tardata, Caenis youngi
4 species (Caenis arwini, Caenis bajaensis, Caenis candida, and Caenis macafferti) aren't included.