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Lateral view of a Male Baetis (Baetidae) (Blue-Winged Olive) Mayfly Dun from Mystery Creek #43 in New York
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.

Lateral view of a Clostoeca disjuncta (Limnephilidae) (Northern Caddisfly) Caddisfly Larva from the Yakima River in Washington
This one was surprisingly straightforward to identify. The lack of a sclerite at the base of the lateral hump narrows the field quite a bit, and the other options followed fairly obvious characteristics to Clostoeca, which only has one species, Clostoeca disjuncta.
27" brown trout, my largest ever. It was the sub-dominant fish in its pool. After this, I hooked the bigger one, but I couldn't land it.
Troutnut is a project started in 2003 by salmonid ecologist Jason "Troutnut" Neuswanger to help anglers and fly tyers unabashedly embrace the entomological side of the sport. Learn more about Troutnut or support the project for an enhanced experience here.

Adirman
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Monticello, NY

Posts: 479
Adirman on Jun 14, 2011June 14th, 2011, 2:18 pm EDT
What are the Cornutas in the BWO family? Are they of the genus Drunella? I'mm loking for pics here on Troutnut and didn't see any. Maybe I missed it? Anyway, these are of the larger BWO's aren't they?

Thanks,

Adirman
Taxon
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Site Editor
Plano, TX

Posts: 1311
Taxon on Jun 14, 2011June 14th, 2011, 2:43 pm EDT
Hi Adirman-

BWO is not a family, but rather, the common name for numerous mayflies, most of which are in family Baetidae, but some of which are in genus Drunella of family Ephemerellidae. And yes, it's Drunella cornuta.
Best regards,
Roger Rohrbeck
www.FlyfishingEntomology.com
Adirman
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Monticello, NY

Posts: 479
Adirman on Jun 14, 2011June 14th, 2011, 3:06 pm EDT
Is the Drunella Cornuta a fairly large BWO? Thank you sir!

Adirman
GONZO
Site Editor
"Bear Swamp," PA

Posts: 1681
GONZO on Jun 14, 2011June 14th, 2011, 4:41 pm EDT
Adirman,

Photos of Drunella cornuta can be found by looking under Drunella lata in the Aquatic Insect Encyclopedia. At the time when Jason photographed his dun and spinner specimens on one of my home waters, D. cornuta (and others) had been lumped (synonymized) with D. lata. That situation has since been rectified (Funk et al., 2008), and all of the duns and spinners in the D. lata section (and probably the nymphs as well) are D. cornuta.

Among the multitude of (mostly small) mayflies that anglers call BWOs, D. cornuta is relatively large. Most that I see range from about 9-12mm. My name for them is Olive Morning Duns, but that name seems unlikely to catch on. :)

Best,
Lloyd
Taxon
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Site Editor
Plano, TX

Posts: 1311
Taxon on Jun 14, 2011June 14th, 2011, 5:29 pm EDT
Adirman-

The (22) mayfly species (of which I am aware) sharing the common name, Blue Winged Olive (BWO), range in size from 3 mm to 11.5 mm in their winged lifstages. So, the answer to your question is: Yes, Drunella cornuta with a winged lifestage size range (of 8.5 mm to 11.5 mm) is arguably the largest BWO.

Acentrella turbida (4-6) mm
Apobaetis futilis (3-3.5) mm
Attenella attenuata (6 - 8) mm
Attenella margarita (6 - 6) mm
Baetis bicaudatus (4 - 5) mm
Baetis brunneicolor (6 - 8) mm
Baetis flavistriga (5 - 6) mm
Baetis tricaudatus (4 - 9) mm
Dannella lita (9 - 11) mm
Dannella simplex (6 - 8) mm
Drunella cornuta (8.5 - 11.5) mm
Drunella cornutella (6.5 - 8.5) mm
Drunella flavilinea (7 - 10) mm
Drunella lata (6.5 - 8.5) mm
Drunella walkeri (8 - 10) mm
Ephemerella dorothea dorothea (6 - 9) mm
Ephemerella excrucians (5 - 8) mm
Iswaeon anoka (5 - 5) mm
Plauditus dubius (3 - 4) mm
Plauditus punctiventris (4 - 5) mm
Procloeon ingens (8 - 9) mm
Procloeon simile (4 - 6) mm
Best regards,
Roger Rohrbeck
www.FlyfishingEntomology.com
GONZO
Site Editor
"Bear Swamp," PA

Posts: 1681
GONZO on Jun 14, 2011June 14th, 2011, 5:45 pm EDT
I'm glad that you confined your list to species found in North America, Roger, though I suspect that Ephemerella (Serratella when last I checked, or is it Torleya?) ignita may have been the little Brit BWO bastard that started it all. :)
Oldredbarn
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Novi, MI

Posts: 2600
Oldredbarn on Jun 14, 2011June 14th, 2011, 7:41 pm EDT
I don't know about the rest of you TroutNuts but I'm going upstairs to bed tonight with a smile on my face and will rest peacefully knowing that we heard today from our "Big Three" "Bug Boys"...All on the same day! All is right in my world. Welcome back fellas...Konchu, Taxon, and Gonzo!

I just may have to take my well worn copy of Justin & Fannie Leonards, "Mayflies of Michigan Trout Streams" to bed with me to help me fall asleep...Not because I haven't already committed it to memory, but because Gonzo sent me the updated list of the new latin names for it and there may be a test! :)

Gute Nacht!

Spence

"Even when my best efforts fail it's a satisfying challenge, and that, after all, is the essence of fly fishing." -Chauncy Lively

"Envy not the man who lives beside the river, but the man the river flows through." Joseph T Heywood
PaulRoberts
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Colorado

Posts: 1776
PaulRoberts on Jun 15, 2011June 15th, 2011, 8:51 am EDT

...
My name for them is Olive Morning Duns, but that name seems unlikely to catch on. :)


Well that makes the most sense, chipping away at what else needs to be known to discover and take advantage of a given emergence besides "What fly should I use??" -habitat, timing, and behavior.

I first found the eastern Drunella's by reading up on them, then going out purposefully to find them. And there they were. An entire hatch waiting for me I'd simply missed previously. They emerged over a short window so I had to be there, on turbulent riffs, and looking at my watch. Fish took both dries and nymphs on a dropper well. The trick was picking the best fish during that window.

As to the Drunells's, and most others, I just called them by their species names: cornuta, or lata (the little later one from what I remember). I now have (or am chipping away at) the western Drunella's and call them grandis, flavilinea, coloradensis, and doddsi. Using species names, where possible, says the most to me.



Taxon
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Site Editor
Plano, TX

Posts: 1311
Taxon on Jun 15, 2011June 15th, 2011, 11:26 am EDT
Hi Paul-

I now have (or am chipping away at) the western Drunella's and call them grandis, flavilinea, coloradensis, and doddsi. Using species names, where possible, says the most to me.


That's all good and well, but please don't ignore our beloved Drunella spinifera and D. pelosa.
Best regards,
Roger Rohrbeck
www.FlyfishingEntomology.com
PaulRoberts
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Colorado

Posts: 1776
PaulRoberts on Jun 15, 2011June 15th, 2011, 12:05 pm EDT
Hi Roger. Haven't seen them yet, although I will certainly appreciate them when I do. They will be truly "beloved" when I find trout rising to them. :)

It's been mostly coloradensis and doddsi -a hint to stream types I frequent.
Konchu
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Site Editor
Indiana

Posts: 498
Konchu on Jun 15, 2011June 15th, 2011, 3:29 pm EDT
Spinifera is generally more prevalent than pelosa, so don't be surprised if you don't come across the latter.
JOHNW
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Chambersburg, PA

Posts: 452
JOHNW on Jun 15, 2011June 15th, 2011, 4:13 pm EDT
,

. My name for them is Olive Morning Duns, but that name seems unlikely to catch on. :)

Best,
Lloyd


I can see it now:
OMG the OMD are on mixed with a bunch of PMD but the fish must have their PhD cause I cant catch a thing. Perhaps when the PED come off I'll be a little less SOL.
JW
"old habits are hard to kill once you have gray in your beard" -Old Red Barn
GONZO
Site Editor
"Bear Swamp," PA

Posts: 1681
GONZO on Jun 16, 2011June 16th, 2011, 6:50 am EDT
LOL. Good one, John.

For anyone who might be interested in more information about one of my favorite hatches (OMD/cornuta), here are some observations from more than 30 seasons of fishing this hatch in PA and NY:

1. On mainstem freestone streams in northeastern PA, I generally see them from about the last week in May through the first week in June. They typically emerge in the morning, and emergence usually coincides with a water temperature of about 58 degrees. Under "normal" conditions (in quotation marks because these conditions seem increasingly rare of late), the hatch lasts a little over an hour, often peaking around or before 10am. My favorite floral "indicator" of this hatch is the blooming of lavender and white wild phlox along stream and river courses. I call it "cornuta weed."

2. During heat waves (when the water temperature does not cool below 58 degrees overnight), they will emerge around dawn. Under unusually cool conditions, they can trickle out through much of the day. On one cool overcast day, the hatch peaked around 2:30 in the afternoon.

3. On the Upper Delaware (esp. W. Branch), a late spring release of very cold water oftens turns hatching schedules topsy turvy. After the release period, cornuta can show up later in the season and later in the day (in the evening).

4. In relatively cool watersheds with a good drop rate (fairly extensive fast water throughout), cornuta can often be found in good numbers from big mainstem streams and rivers up through tiny tributaries and headwater streams. Anecdotally, it does seem to be sensitive to organic pollution. On one favorite stream, the population has virtually disappeared in recent seasons after an upstream waterpark dumped a slug of untreated sewage into a tributary. Some other mayflies (like the sturdy E. invaria) seem to have survived this event more successfully.

5. Emergence is later on cold tribs. On one especially cold headwater, I usually see them emerge around the second week of July. This presents the opportunity to follow the hatch as it moves upstream. In some memorable seasons, I have fished this hatch for nearly two months.

6. Rises to the emerging duns in fast water are dramatic, pyramid-shaped slashes, similar to rises to some emerging caddisflies. Because one often sees mating flights of male Hydropsyche in the morning at this time, it can be easy to mistakenly attribute the rising to the caddisfly activity. When I first encountered this hatch many moons ago, I wasted precious time fishing caddis imitations to the cornuta emergence before I realized my mistake. On the streams I fish, there is usually little or no competition for the trout's attention during the cornuta emergence, making fly selection easy if you are prepared for the hatch.

7. The overall emergence period coincides with the first appearance of the Paragnetina media and Haploperla brevis stoneflies and the Isonychia mayflies. (You'll see the evacuated shucks of all of these in evidence on streamside rocks during cornuta time.) In the evenings, a host of mayflies are emerging, and it is this abundance of evening hatches that often means that fewer anglers focus on the morning cornuta activity: The activity of Ephemerella invaria (Large Early Sulphurs/Light Hendricksons) is lingering and Ephemerella d. dorothea (Pale Evening Duns/Little Sulphurs, when present) is just beginning. On streams that have them, Ephemera guttulata (Green Drakes/Coffin Flies) and Ephemera simulans (Brown Drakes) command the attention of big fish hunters. M. vicarium (March Browns/Grey Foxes) and Epeorus vitreus (Yellow Quills/Pink Ladies) provide somewhat sporadic, but often worthwhile opportunities. One of the largest wild browns I've caught during this period, a hefty 22" male, came to an emerger (a wet fly to match the underwater emergence) during the unpredictable vitreus hatch. That fish edged out a number of 16-21" browns that came to the cornuta emergence.

8. Although the fast-water dry-fly fishing to cornuta can be as exciting as any I've experienced, it is a mistake to neglect the nymph. The nymphs fish well throughout the period before and (perhaps more surprisingly) after the actual emergence on the surface. I'd estimate that three-quarters of all the fish that I've caught during this hatch (and most of the larger fish) came to the nymphs.

9. Other Eastern Drunella can provide similar, though more limited opportunities. D. cornutella, D. lata, and even D. tuberculata and D. walkeri can be found in many of the same streams. Their later emergence often means that marginal water temps can complicate things, and none of these species seem nearly as abundant in the streams that I fish. Of them, D. cornutella is the most abundant species I encounter, but it still pales when compared to cornuta. For our purposes, cornutella is nearly identical to cornuta, but smaller (6-8mm, about the size of E. dorothea or D. lata), and it emerges later in the season (often in July).

10. I'm not really betraying any cherished secrets here. Few can tear themselves away from the more popular evening hatches at this time of year, and I write all of this knowing that the emergence is over on most (larger) streams and this information will probably be forgotten by this time next year. :)

PaulRoberts
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Colorado

Posts: 1776
PaulRoberts on Jun 16, 2011June 16th, 2011, 7:11 am EDT
Wow. Thanks for sharing your notes Lloyd.

I understand #10, in that there is so much going on on good streams that no one can cover it all. In many (but not all) places, I found that sharing and edifying others tended to bring more and better info in return, overall.
GONZO
Site Editor
"Bear Swamp," PA

Posts: 1681
GONZO on Jun 16, 2011June 16th, 2011, 7:29 am EDT
If you were still here in the East, Paul, I'd worry that I may have spilled (too many of) the beans. Most of my fellow Easterners have their own favorite hatches at this time of year, and my personal affection for this hatch does not appear to be shared by very many. Unfortunately, my love of cornuta went mostly unrequited this season, but I'm still looking forward to its emergence on the tribs. (Though, in all honesty, the hatch-matching aspect on those waters is often an affectation. I've had eager little trib fish willingly take an Elk-hair Caddis during the cornuta emergence.)
Oldredbarn
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Novi, MI

Posts: 2600
Oldredbarn on Jun 16, 2011June 16th, 2011, 8:43 am EDT
Lloyd...Paul,

I have said this before that during the "Big Fly Mania"...Brown Drakes-Hex...if a guy were to ignore these he would generally have the whole river to himself and some very nice hatches to boot. The night hawks are in bed until late afternoon and usually don't show up until late to stake out their area for the evening fish.

In the later afternoon I used to have some nice fun small fly fishing to P anoka (now Plauditus p) just prior to E dorothea showing up...This tiny fly, for the most part, was completely ignored by my fellow anglers up that way who just couldn't get their minds around fishing such a small bug when there were relative giants around. I use to head back up a few weeks after my normal late May trip and be around up there around Father's Day. You usually got a couple good hours of fishing in before needing to switch to some stouter tippet and something to cover the E dorothea.

It reminds me of your story.

Two short little tricks for that time of year...1) Folks have their famous Hex spots on the river, but they are not limited to these areas alone...There is mucky prime habitat for Hex through out a river system usually along the edges near swamps...I have stayed late and fished to good Hex hatches in spots that were angler free because they were all stuck in the traffic jam in the so-called "hot-spots" for the bug.Those spots look like the Lodge in downtown Detroit when the Hex is on...Asshole-to-elbow-so-to-speak. Halting your fishing time to do a little research pays off in spades sometimes, but I don't need to tell you two this!

2) During the time of year when the large bugs are about and the night-time anglers are in dreamland dreaming of big fish in the dark...I have been known to toss these larger bugs about during the day to some surprising results.

Spence

A few years back on my way to the "Hex" water I caught a nice 18" Brown on a dry fly Iso pattern right in broad daylight...I must admit that the lure of night-time fishing is pretty strong around these parts...I think that at the right time it can be a guys best chance for that hog-of-the-year...Just look at Gates' Hog chart and it's no surprise that so many big fish fall at that time...Some guys think that the trout season is over after the Hex and for others it may be the only time they actually fly fish...



"Even when my best efforts fail it's a satisfying challenge, and that, after all, is the essence of fly fishing." -Chauncy Lively

"Envy not the man who lives beside the river, but the man the river flows through." Joseph T Heywood
Entoman
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Northern CA & ID

Posts: 2604
Entoman on Jun 16, 2011June 16th, 2011, 9:13 am EDT
Gonzo -
My name for them is Olive Morning Duns, but that name seems unlikely to catch on. :)

Too bad, as I think it an elegant solution. Fishing a hatch of "Morning Olives"... Now that's soothing to the ear.

Out West, an effort gathering a little steam is trying to reserve Blue Winged Olive for describing the prolific medium sized Drunella species while calling Baetids Olive or Iron Quills. We have an additional problem with our large Drunella species. Legend has it that some unidentified Idaho guide or shop owner called them Green Drakes and that unfortunate handle has stuck like Gorilla Glue. Great Blue Winged Olive is just too much of a mouthfull for many, which is too bad. "Green Drake" should be reserved for the Ephemerids of Eastern and European origin, though the former's regrettable slippage from it's status as a major hatch in many locations and the Brits insistance on referring to the latter as simply "Mayfly" doesn't help.

Kurt
"It's not that I find fishing so important, it's just that I find all other endeavors of Man equally unimportant... And not nearly as much fun!" Robert Traver, Anatomy of a Fisherman
Jmd123
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Oscoda, MI

Posts: 2474
Jmd123 on Jun 16, 2011June 16th, 2011, 9:26 am EDT
"Some guys think that the trout season is over after the Hex and for others it may be the only time they actually fly fish..."

All the better for us, Spence! The Rifle doesn't get a Hex hatch, but at the same time of the year is the Light Cahill hatch (it's starting now, I saw some hatching on the Au Gres on Monday evening). All the guys can go after the Hex while I am working those "little white ones", as my professor-mentor Terry used to call them all those years ago on the Maple...BTW I learned how to fly fish on the Hex hatch and for many years didn't think it worth going out in daylight, either! "Geez, those fish can SEE ME, they're never going to bite..." Yeah, and there's nobody else out there because they are all thinking the same thing!

Jonathon
No matter how big the one you just caught is, there's always a bigger one out there somewhere...
GONZO
Site Editor
"Bear Swamp," PA

Posts: 1681
GONZO on Jun 16, 2011June 16th, 2011, 10:45 am EDT
Fishing a hatch of "Morning Olives"... Now that's soothing to the ear.

I agree, Kurt. Unfortunately, I suspect that both of our efforts to popularize better or more sensible names for these bugs will have the proverbial "snowball in hell" chance of succeeding. Perhaps it's one of those cases where the confusion we know is preferable to the confusion we don't know. :)

...P anoka (now Plauditus p)....

I believe that P. anoka is now Iswaeon anoka, Spence. (Plauditus punctiventris is synonymized with Pseudocloeon myrsum and Pseudocloeon punctiventris.) If I'm not mistaken, that particular aspect of sorting out the former "Pseudos" may have involved some degree of misidentification on the scientific end. Konchu would know the details, but (as I remember it) it made my head spin. At any rate, the (probably laudable) effort to call these bugs "Pseudos" in the fly-fishing lit. went down in flames with the revisions (much like Caucci and Nastasi's earlier effort to suggest that cornuta be called "cornuta"). Anyone for "Plaudits" and "Iswas"?
Oldredbarn
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Novi, MI

Posts: 2600
Oldredbarn on Jun 16, 2011June 16th, 2011, 11:38 am EDT
but (as I remember it) it made my head spin.


Gonzo...Tell me about it...At times I come very close to just keeping my own journals and naming them as I please...They aren't going to get it all worked out by the time they sprinkle my ashes on the old Au Sable anyway!

How come when I make little jokes about McCafferty and his renaming bugs after himself no one bites on it...:) You know, I think, there used to be a procedure and if it's been tossed to the four winds maybe you and I could name a few...What did you say about a "snowballs chance in hell?!"...

Angler's names may not be as poetical sounding as the latin but they have sure as hell been rather more colorful!..."The Never-Fall Spinner"...don't ask! The "Mattress Thrasher"...don't ask again...:)...The "Angler's Curse", Cornie's Quill, The Rat-Faced Mcdogal (sp?), Blue-Winged Olive is hard to beat as is "Pale Morning or Evening Dun", The White-Gloved Howdy, "The Michigan Caddis" (no one seems to know how this ever became applied to the Hex here but it goes way back...I had a great aunt tell it to me a long time ago...), The Picket-Pin", "The Coffin-Fly", The Whirling Dun...And these are only the one's I can recall at the moment and don't include the "newer" ones like "Knocked Down Dun", The Circus Peanut, the Chernoble (sp?) Ant etc...I guess we don't really need the scientist's to really confuse ourselves, eh!?

An odd aside...For the record Shawn Davis called the Stanley Cup Finals and Boston winning it all! Tony mentioned he wanted them to so Mark Recchi (sp?) could get another Cup...He's (Tony) a bit sentimental like this old dutchman when it comes to ice hockey...You should see the photos of his boy in his hockey gear he sends me from time-to-time! The boy has the serious look of a future Stanley Cup champ...You heard it here first...

Spence
"Even when my best efforts fail it's a satisfying challenge, and that, after all, is the essence of fly fishing." -Chauncy Lively

"Envy not the man who lives beside the river, but the man the river flows through." Joseph T Heywood

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