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> > Invaria - Dorothea confusion

This topic is about the Mayfly Genus Ephemerella

This genus contains the legendary Hendricksons and Sulphurs of the East and the equally important Pale Morning Duns of western waters.

No scientific name in American angling literature is more renowned and at the same time capable of more confusion than the genus name "Ephemerella." It is important that anglers have a good overall grasp of its taxonomic history if they are to make any sense out of the rich literary heritage involving this mayfly name.

By the time American angling literature began to take serious note of entomology in the decades of the early to mid 20th century, Ephemerella was considered a "super-genus" in the family Baetidae, containing all of the important species to anglers in the subfamily Ephemerellinae. Taxonomists organized them by association with "type" species that were referred to as "groups" within this very large and unruly genus.

This organizational structure held sway until the 70's when they were recognized as separate from the Baetidae with their own family, the Ephemerellidae. The "groups" (after a little name changing and reorganization) were given subgenus status, but in conformance with taxonomical convention,the nomenclature retained the use of the name Ephemerella when referring to individual species genus status. More change occurred towards the end of the century as consensus formed around the subgenera achieving full generic status. The broad use of Ephemerella was then dropped in favor of the new generic names.

These changes were necessary in that they addressed many problems exposed in older taxonomies. Unfortunately, all during this period the changes were reported with varying degrees of accuracy and acceptance. For anglers this was exacerbated by the continued use and reliance on older entomology texts in many circles. Be that as it may, recent or updated angler entomologies now recognize that many of the old Ephemerella species are spread out among several genera in the Ephemerellidae family. These include the various Blue-Winged Olives and Western Green Drakes of the Drunella genus as well as several important species scattered in genera like Attenella and Serratella, to name a few.

Despite these revisions in classification, the Ephemerella genus still contains arguably the most important species in North America, and remains a "super-genus" to anglers.

There is a lot of variation; refer to the genus species hatch pages for details. Read more...

There are 137 more specimens...

The Discussion

EntomanFebruary 1st, 2012, 6:14 am
Northern CA & ID

Posts: 2604
The following is from an older post of Gonzo's.

It's been my suspicion for quite some time that a good part of the credit given to dorothea for creating the later, lighter-colored "little sulphur" hatch should probably go to the same species (or species complex) that creates the earlier, larger, darker hatch--E. invaria. Many anglers who fish the small suphurs on valley limestone streams in my home state believe (or have been led to believe) that they are fishing the dorothea hatch. Close inspection of the mayfly that causes the activity usually doesn't bear that out. Most of the true dorothea hatches seem to come from mountainous areas where the streams are faster and have rockier bottoms.

All of the specimens in this section are from PA, and this seems to provide a good case in point. This specimen and the nymph (#766) are good examples of dorothea, and they both came from sections of the Brodheads in the Poconos. The other specimens came from big limestoners and appear to be invaria. Notice that all of the dun and spinner specimens, except for this one, have banded tails (dark markings at the segments). As far as I know, this is not characteristic of the Eastern version of dorothea (E. dorothea dorothea), but it is a trait of invaria.


I've often speculated the same thing as I've seen examples of eastern invaria that look virtually identical to some of infrequens out West. Compare the specimen I posted http://www.troutnut.com/specimen/1013 to this one of Spence's http://www.troutnut.com/im_user_ident/picture_219_large.jpg Any thoughts guys?
"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
PaulRobertsFebruary 1st, 2012, 1:06 pm
Colorado

Posts: 1776
Well...dunno.

I fished a stream in Central NY (some may know here) called Owasco (Lake) Inlet. It's a roiled (due to clay) "freestone" with riffle/pool and some ground water influx as it cuts somewhat deeply into its valley. It also has a lot of silt due to the natural clay beds and some farming activity.

It had both "species" as best as I understood it. I keyed individual nymphs out and have some images (35mm transparencies). As I understood it, the larger (#14) invaria's came earlier (May) and the smaller (#18) dorothea's came later (June/July). And yes, my images show banded cerci on teh "invaria" and none on the "dorothea".

As to emergences, as I understood it, invaria emerged from riffles in May (got airborne quick) and later "dorothea" seemed more generalized in habitat, and were even apt to emerge from silty shorelines. The "dorothea" emergence was much denser and I never got to fish a spinner fall bc they fell at night (being summer). Man were those spinners dense though. I have some flash photos of my yellow lab standing in the stream surrounded by what looks like a myriad of stars.

Could it be that my "invaria" were early (and larger) dorothea? Or..vice versa? I did key some nymphs though so I was (at the time) fairly certain I had both species, and that they behaved as described above.

Will be curious what others say.
OldredbarnFebruary 1st, 2012, 3:39 pm
Novi, MI

Posts: 2591
An angler's view...Not a scientific one.

I tend to feel that the larger invaria 14/16 are the middle to late May emerger and E dorothea is more a #19/20 and is a very creamy yellow/with orange hightlights...dorothea can show up in late May but really gets rolling in northern MI in the first week or so of June.

The bug I'm holding in my hand I took for E invaria and would call that a med dun colored wing...E dorothea is lighter dun to cream wing and noticably smaller. For lack of the ability to really describe it...invaria has olivish hints where dorothea has orangish hints. Same places.

I have noticed though that invaria can tend more to the creamy side at times...Not sure why, but there you have it. The "sulpher hatch" is another one like BWO's...Guys talk sulphers in a general way and are not always sure if it's the two in question or even a March Brown...They can all be around sometimes at the same time...

I have told the story about the very tiny creamy mayflies I watched on a window from inside a bar...I'm still not sure if those were maybe the "true" E dorothea or centroptilium (sp?)...It almost appeared as if the three flies were carbon copies of each other but one was a 22 or so, one a 19, and one a 16? To the naked eye, the only thing that looked different was their size...

Maybe this year I'll stop for a moment, set the damn rod down, and get them to pose...:)

Spence

I have been in hatches of invaria that were incredible...One year I was floating the South Branch above Daisey Bend when the bugs got so thick we pulled the boat over and both of us fished...They were on our caps, on our rods, all over the boat. The fishing at the height of this was rough...Really difficult...I would cast and see 3/4 naturals just in front of my fly and 3/4 just behind it...Even with all these duns on the water the fish were busy on the nymphs before that even made it to the surface...There must of been an incredible amount under the water...The dry fly fishing really didn't improve to after it started to slow back down...

Could this be?...When there are a zillion nymphs in a fishes face and he's all geared up chasing them, maybe he really doesn't need to see bugs that have made it to the surface...Afterwards, still geeked up, he's looking around and sees the stragglers floating by.
"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
EntomanFebruary 1st, 2012, 5:19 pm
Northern CA & ID

Posts: 2604
Paul & Spence -

It had both "species" as best as I understood it. I keyed individual nymphs out and have some images (35mm transparencies). As I understood it, the larger (#14) invaria's came earlier (May) and the smaller (#18) dorothea's came later (June/July). And yes, my images show banded cerci on teh "invaria" and none on the "dorothea".

I tend to feel that the larger invaria 14/16 are the middle to late May emerger and E dorothea is more a #19/20 and is a very creamy yellow/with orange hightlights...dorothea can show up in late May but really gets rolling in northern MI in the first week or so of June.

The bug I'm holding in my hand I took for E invaria and would call that a med dun colored wing...E dorothea is lighter dun to cream wing and noticably smaller. For lack of the ability to really discribe it...invaria has olivish hints where dorothea has orangish hints. Same places.

I concur with both your findings. Out West it's the reverse, with the dorothea subspecies being larger and coming first followed by the smaller excrucians. Another puzzle is that the western dorothea is a much closer match with invaria in terms of body and wing conformation (including banded tails) than with it's eastern subspecies! It seems there is a lot to sort out with the pale complex of invaria / d.dorothea / d.infrequens / excrucians. Heck, some western angler/entomologies even report E. tibialis as a large (14) creamy orange mayfly!

BTW - Color doesn't seem to be a good way to separate them either except as they appear in particular watersheds. From a universal standpoint any of them can be anywhere across the creamy yellow/olive/orange spectrum. Size too, as they come in a large 14 to a small 18, and as Gonzo points out, not even invaria is above suspicion in this regard.

Perhaps Sayfu/Doublespey is right, we should just call them all "pale duns" of the Ephemerella genus until the Ento's work it out!:)

...maybe the "true" E dorothea or centroptilium (sp?).

This happens a lot, Spence. I have long held that angler reports of pale ephemerellids below size 18 are actually Centroptilium. Since they aren't thought of as a possibility (supposedly being only warm water species), tail counts aren't noticed. When we consider the possibility later, we can't remember how many they had! I can't tell you the number of dubious glances I've received from guys when I tell them that size 20 PMD the fish were taking wasn't one.
"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
OldredbarnFebruary 2nd, 2012, 1:03 pm
Novi, MI

Posts: 2591
This happens a lot, Spence. I have long held that angler reports of pale ephemerellids below size 18 are actually Centroptilium. Since they aren't thought of as a possibility (supposedly being only warm water species), tail counts aren't noticed. When we consider the possibility later, we can't remember how many they had! I can't tell you the number of dubious glances I've received from guys when I tell them that size 20 PMD the fish were taking wasn't one.


In 1995 on Dupuy's Spring Creek we had some smaller, maybe 20's?, creamy colored mayflies that came pretty hard later in the day after the PMD's...Though it is an extreme guess at this late date, I have thought that some Centroptilium cousin may have been this bug...

The ones I watched through the glass at the Lovell's bar had two tails, split at quite an angle...This was early June 2002 (whenever it was that my Wings clinched the Cup)...I always had a feeling of an after dark hatch, but no way can I be sure...I should of put the damn beer down, eh!? The river runs right out back of the tavern, but there is a lake not too far away as a mayfly flies. (?)

My fishing buddy asked me, "Did you see any fish taking them?" I had to say no since my observation was coming from the bar, post who knows how many beers...:) "Well" he said, "This is all speculation then and of little to no matter...Tie some up and tell me how it goes."

I had arrived early and placed the back of my chair against the short side of a long table...Facing the TV...Sometime during a break in the game I turned to realize I had a full table of strangers sitting with me...Lovell-ites...Not sure if they were helping themselves to my pitcher or I was draining it myself...My boys were on the verge of another Cup, I was very, very, happy, and didn't give a damn! "Sweetie! Could you bring us a couple more of these? They seem to be evaporating."

I was glad I had walked that night and left the car parked back at the cabin...;)

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
PaulRobertsFebruary 2nd, 2012, 1:15 pm
Colorado

Posts: 1776
I'd have to dig em up but there are documented Ephemerella "sulpher" emergences, notably on more southern tailwaters, in which multiple broods occur giving rise to short growth-duration emergences of "miniaturized" individuals.
EntomanFebruary 2nd, 2012, 1:46 pm
Northern CA & ID

Posts: 2604
Hi Spence,

Yeah, on Dupuy's those were Centroptilum asperatum, formerly known as C. elsa. Little Sulfur Spurwing and Little Pale Watery are the two common names most used for this genus, regardless of species or geography. Schwiebert writes briefly of fishing over them at Nelson's with Joe Brooks, and in circumstances just as you described.
"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
EntomanFebruary 2nd, 2012, 1:49 pm
Northern CA & ID

Posts: 2604
Hi Paul,

I'd be very interested to hear about them!
"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
PaulRobertsFebruary 2nd, 2012, 3:37 pm
Colorado

Posts: 1776
I'll see what I can find. I think I have it somewhere.
GutcutterFebruary 5th, 2012, 12:26 pm
Pennsylvania

Posts: 470
...Out West it's the reverse, with the dorothea subspecies being larger and coming first followed by the smaller excrucians. Another puzzle is that the western dorothea is a much closer match with invaria in terms of body and wing conformation (including banded tails) than with it's eastern subspecies! It seems there is a lot to sort out with the pale complex of invaria / d.dorothea / d.infrequens / excrucians...
BTW - Color doesn't seem to be a good way to separate them either except as they appear in particular watersheds. From a universal standpoint any of them can be anywhere across the creamy yellow/olive/orange spectrum...


Fascinating stuff.
I'm a fisherman, and not an Ento-Man, but it would be nice to find out more about this.
In late July/early August, on the PV spring creeks, there is a spinnerfall beginning most mornings around 0930 of pale colored size 18 mayflies (infrequens?), then around 1100, a hatch of size 18 pale greenish colored mayflies (infrequens?), followed by a hatch of pale orangish size 20 mayflies (dorothea?) around 1600 and finally a size 20 rusty spinner fall (dorothea?) at and beyond dusk.
Am I guessing correctly?
I would also like to hear Matt's opinion, as he probably has more experience on the PV spring creeks than all of us combined.

...Perhaps Sayfu/Doublespey is right, we should just call them all "pale duns" of the Ephemerella genus until the Ento's work it out!:)


Amen to that!
All men who fish may in turn be divided into two parts: those who fish for trout and those who don't. Trout fishermen are a race apart: they are a dedicated crew- indolent, improvident, and quietly mad.

-Robert Traver, Trout Madness
PaulRobertsFebruary 6th, 2012, 11:17 am
Colorado

Posts: 1776
I think your AM one is likely a Drunella -D. lata maybe. The later one is probably E. dorothea -unless it's a Heptageniid. Next time check for two or three tails.
PaulRobertsFebruary 6th, 2012, 1:14 pm
Colorado

Posts: 1776
I'd have to dig em up but there are documented Ephemerella "sulpher" emergences, notably on more southern tailwaters, in which multiple broods occur giving rise to short growth-duration emergences of "miniaturized" individuals.

Kurt, I cannot find the article. It was online and I may have only had it bookmarked although I'm surprised I don't have it saved as well. It may turn up yet.
EntomanFebruary 6th, 2012, 5:54 pm
Northern CA & ID

Posts: 2604
No problem, it'll turn up sooner or later. Thanks for taking the time to look! I seem to remember something along those lines myself and will look as well. I believe the consensus among biologists is that ephemerellids aren't multi-brooded. There is evidence of disparate strains of the same species hatching at different times of the season, but they are all still univoltine. If I remember right, there is a connection between this phenomenon and longer growing seasons.
"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
Feathers5February 7th, 2012, 10:52 am
Posts: 287Gutcutter & Oldredbarn, I tie my later dorothea's on a size 19 & 7/16 hook. Anymore than that and you'll spook them trout.

Bruce, Goose, Lastchance, Feathers5.


PS. For some reason I had to register again from this email address.
OldredbarnFebruary 7th, 2012, 12:10 pm
Novi, MI

Posts: 2591
Bruce, Goose, Lastchance, Feathers5.


PS. For some reason I had to register again from this email address.


:) Now that I've passed 58 (ouch) I have a hard time remembering my password too...;) One day they will just insert a tiny chip in our ear lobes and we will be all set! They will know where we are at all times. No longer will we fear getting lost in the woods. It will have our id #/savings account info/ and at Speedway we will just be able to walk through some detector device and all our gas and iced teas will be charged to our account...They better hurry though, because I'm fading fast.

Spence

I understand your size 19 comment, but with different hook manufacturer's unfortunately we don't always have uniformity...I carry around a little metric ruler I stole from my wife's sewing room (only after I caught her using my best snips to open up button holes on garments she was making) and I measure some of these critters we emulate...Well, attempt to emulate. I have these written down and I measure the working shank area against this and find a hook that's right...Who knew, that when I was a little shit, hanging out on the street in my dress leather, thinking I was all that in junior high, that one day I would wake up to find I had morphed in to a Nerd?! :)...a rather old one.
"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
PaulRobertsFebruary 7th, 2012, 1:21 pm
Colorado

Posts: 1776
...There is evidence of disparate strains of the same species hatching at different times of the season, but they are all still univoltine. If I remember right, there is a connection between this phenomenon and longer growing seasons.

You likely have that right... I am surprised I don't have that article. I remember thinking, Man! the more you look, the more complicated it gets. Just be sure you have every size and shade covered, and keep your eyes open.
WbranchFebruary 7th, 2012, 1:37 pm
York & Starlight PA

Posts: 2506
Hello to everyone!

Last Monday I went to the computer and the little green ready light on my Dell Dimension E510 was not lite. I thought maybe my wife had turned off the entire computer but she said she had not. Then I thought maybe the computer was "sleeping" and I tried pressing the button a few times to no avail. Tried diconnecting the power cord and reconnecting - still nothing so I unhooked all the cables and connections and took it to the least expensive hourly rate guy in the area and later that day he called to tell me the motherboard was cooked and it was not worth the money to fix it. So I went and bought a new Dell 570 Inspiron with a Dell 21.5" monitor and am now back in business. The repair guy was able to DL all my pictures and documents from the old hard drive to the new machine so I'm pretty happy. I especially like the big screen compared to my old little square format of about 15".

I haven't had a chance to read the initial post and accompanying comments but did see this comment;

"In 1995 on Dupuy's Spring Creek we had some smaller, maybe 20's?, creamy colored mayflies that came pretty hard later in the day after the PMD's...Though it is an extreme guess at this late date, I have thought that some Centroptilium cousin may have been this bug..."

As some of you know I had the good fortune to be able to spend the months of June, July, and August in Montana during the years 1969 - 1972. Much of that time was spent camped on Armstrong Spring Creek (on the far side of the creek below the bull pen) and I too witnessed there, and on Nelsons's, the little #20 mayfly that looked similar to what we then called infrequens. It never emerged with infrequens, always later in the afternoon, from about 5:00 - 7:00. It was an enigma and the fish boiled and boiled but I seldom caught a fish. We tried all sorts of wet flies (we didn't know what an emerger was back then) although a fellow did develop the loopwing long before any of the more famous tiers/writers started to talk about it.

Anyway I wrote George Anderson a letter one winter asking him about the little mayflies and he also referred to them as Centroptilium. Now I have a much better pattern to imitate these flies and I need them as they are also found on the Missouri.




Catskill fly fisher for fifty-five years.
EntomanFebruary 7th, 2012, 5:09 pm
Northern CA & ID

Posts: 2604
Ah, computers. Don't you just love 'em? Good thing it was the motherboard, not the drive that fried! Glad you are back, was beginning to wonder. Thought you were maybe chasing steelhead!:)
"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

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