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 a striking caddis larva with an interesting color pattern on the head. Here are some characteristics I was able to see under the microscope, but could not easily expose for a picture:
- The prosternal horn is present.
- The mandible is clearly toothed, not formed into a uniform scraper blade.
- The seems to be only 2 major setae on the ventral edge of the hind femur.
- Chloride epithelia seem to be absent from the dorsal side of any abdominal segments.
Based on these characteristics and the ones more easily visible from the pictures, this seems to be Grammotaulius. The key's description of the case is spot-on: "Case cylindrical, made of longitudinally arranged sedge or similar leaves," as is the description of the markings on the head, "Dorsum of head light brownish yellow with numerous discrete, small, dark spots." The spot pattern on the head is a very good match to figure 19.312 of Merritt R.W., Cummins, K.W., and Berg, M.B. (2019). The species ID is based on Grammotaulius betteni being the only species of this genus known in Washington state.
- The prosternal horn is present.
- The mandible is clearly toothed, not formed into a uniform scraper blade.
- The seems to be only 2 major setae on the ventral edge of the hind femur.
- Chloride epithelia seem to be absent from the dorsal side of any abdominal segments.
Based on these characteristics and the ones more easily visible from the pictures, this seems to be Grammotaulius. The key's description of the case is spot-on: "Case cylindrical, made of longitudinally arranged sedge or similar leaves," as is the description of the markings on the head, "Dorsum of head light brownish yellow with numerous discrete, small, dark spots." The spot pattern on the head is a very good match to figure 19.312 of Merritt R.W., Cummins, K.W., and Berg, M.B. (2019). The species ID is based on Grammotaulius betteni being the only species of this genus known in Washington state.
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Martinlf on Dec 23, 2006December 23rd, 2006, 12:30 pm EST
OK, this olive nymph seems to have a good bit of grey in it. I know colors vary a lot among baetids, but I'm wondering about a good general color for shucks. And nymphs. Are most of them more olive than this? Or is it too hard to generalize? Also, I notice darker and lighter segments in the abdomen. I've noted this in subvaria's and try to get a lighter band just ahead of the darker tail segment in nymphs I tie for them. Perhaps this is a good idea with baetid nymphs as well.
"He spread them a yard and a half. 'And every one that got away is this big.'"
--Fred Chappell
--Fred Chappell
GONZO on Dec 26, 2006December 26th, 2006, 1:28 pm EST
Louis,
Baetidae includes so many species that generalization about color is virtually impossible. Even the common name "blue-winged olive" is a nasty joke. Adult (and nymph) body colors range from yellow to chartreuse to olive to olive-brown to reddish-brown to dark brown. Wing colors vary from very light grey (nearly white) to very dark grey (nearly black). Although color may be less significant in tiny mayflies, the only way to be accurate is to become familiar with local species.
That said, however, this might be one instance where generalized patterns with blended or "spectrumized" dubbing can be very useful. Until patterns based on specific local color variations can be devised, a light and dark "baetis" nymph in useful sizes (say #16-22) will probably serve to fool all but the fussiest trout. Make one dubbing blend lighter and more olive, and the other darker and more brown. A similar approach could be used on duns and shucks (utilizing a darker and lighter blend of all the colors listed in the first paragraph). I think this is a good compromise approach for many genera/species that display wide color variations.
By the way, as an aid to developing more specific imitations, some of the most important local (PA) species are B. tricaudatus, B. intercalaris, Diphetor hageni, Acentrella turbida, and Plauditus punctriventris (listed in my totally subjective order of significance).
Baetidae includes so many species that generalization about color is virtually impossible. Even the common name "blue-winged olive" is a nasty joke. Adult (and nymph) body colors range from yellow to chartreuse to olive to olive-brown to reddish-brown to dark brown. Wing colors vary from very light grey (nearly white) to very dark grey (nearly black). Although color may be less significant in tiny mayflies, the only way to be accurate is to become familiar with local species.
That said, however, this might be one instance where generalized patterns with blended or "spectrumized" dubbing can be very useful. Until patterns based on specific local color variations can be devised, a light and dark "baetis" nymph in useful sizes (say #16-22) will probably serve to fool all but the fussiest trout. Make one dubbing blend lighter and more olive, and the other darker and more brown. A similar approach could be used on duns and shucks (utilizing a darker and lighter blend of all the colors listed in the first paragraph). I think this is a good compromise approach for many genera/species that display wide color variations.
By the way, as an aid to developing more specific imitations, some of the most important local (PA) species are B. tricaudatus, B. intercalaris, Diphetor hageni, Acentrella turbida, and Plauditus punctriventris (listed in my totally subjective order of significance).
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