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The Specimen

Ephemerella invaria (Sulphur Dun) Mayfly NymphEphemerella invaria (Sulphur Dun) Mayfly Nymph View 8 PicturesThis small Ephemerella invaria nymph was at least a month away from emergence.
Collected April 19, 2006 from the Beaverkill River in New York
Added to Troutnut.com by on April 21, 2006

The Discussion

MartinlfDecember 23rd, 2006, 5:50 pm
Moderator
Palmyra PA

Posts: 2902
OK, the invaria nymph shows the same lighter darker dorsal bandsand the solid dark ventral color on the abdomen as the subvaria, though its size makes me wonder if it is immature and may darken. For many considering this kind of detail will be superfluous, but for some of us nuts who like to fritter away the hours considering the possible uses of such information, this may confirm the claims of those who like to leave streaks in when blending fur, or perhaps even the claims of Caucci and Nastasi who promote a spectrumized dubbing.
"He spread them a yard and a half. 'And every one that got away is this big.'"

--Fred Chappell
DarkDunApril 18th, 2007, 6:52 pm
Posts: 16Just looking at this post today since we have some Sulpurs hatching around here right now and invariably I find that a vareigated fly imitation is much better at getting a take than so many monocromatic imitations that are commercially tied. This goes for the tail, the legs (hackle) and the body of my emergers. For this hatch I find that drys only work for a few minutes early in the hatch and then a emerger is a must for the next two hours or I will go fishless. I usully band or variegate my nymphs, emergers and dries like the naturals body.
TroutnutApril 18th, 2007, 7:07 pm
Administrator
Bellevue, WA

Posts: 2539
This isn't a mature nymph, but your observation is probably even more true for mature ones. When you get really close up, you can see a wide variety of color patterns and shades in these invaria nymphs. There are differences in between nymphs, but often also several color shifts on a given nymph. I might not go so far as to compare it to army camouflage, but it's something like that.
Jason Neuswanger, Ph.D.
Troutnut and salmonid ecologist
KonchuApril 18th, 2007, 7:55 pm
Site Editor
Indiana

Posts: 496
What Jason says is incredibly true! Some also have bold stripes going the length of the body. Possibly this breaks up their outline from above. The invaria nymph has lots of color variation. I won't open a can of worms by saying any more. :)
TroutnutApril 18th, 2007, 8:29 pm
Administrator
Bellevue, WA

Posts: 2539
I would like to peer into that can of worms. :)

I didn't realize invaria came in a striped variety. Does subvaria, too?

I'd like to know what you think of some of the older 2004 specimens I have listed under aurivillii on this site. They're not good enough pictures to key the specimens, but they have an awfully distinctive look -- maybe you'll recognize them.
Jason Neuswanger, Ph.D.
Troutnut and salmonid ecologist
KonchuApril 18th, 2007, 8:45 pm
Site Editor
Indiana

Posts: 496
Don't recall seeing as much striping in Ephemerella subvaria. Ephemerella invaria, on the other hand, is all over the board. Some Eurylophella have this striping variation, too.

Those "2004" specimens that you called aurivillii indeed could be aurivillii. I wouldn't rule it out. Where were these taken? Wisc or the UP?
TroutnutApril 18th, 2007, 8:49 pm
Administrator
Bellevue, WA

Posts: 2539
Northwest Wisconsin, Bois Brule drainage and the tributaries of the White, in Bayfield and Douglas counties.
Jason Neuswanger, Ph.D.
Troutnut and salmonid ecologist
KonchuApril 18th, 2007, 8:53 pm
Site Editor
Indiana

Posts: 496
Thanks for the info, Jason.

While we're on the subject of invaria...dare I mention the name rotunda?
TroutnutApril 18th, 2007, 10:16 pm
Administrator
Bellevue, WA

Posts: 2539
Well, all I really know is that rotunda and invaria were synonymized. Is there still some conflict among entomologists about this?

One thing I'd like to know is whether they were determined to be two distinct varieties too similar to be called separate species, or if the initial descriptions simply underestimated the variability in invaria.
Jason Neuswanger, Ph.D.
Troutnut and salmonid ecologist
KonchuApril 19th, 2007, 5:25 am
Site Editor
Indiana

Posts: 496
initial underestimations of overall variability (or complete failure to recognize any) and lack of differences between specimens that hold down names led to a decision to recognize the names invaria and rotunda (and several others) as equivalent

however, some people notice two forms or broods in local areas; one they call rotunda, one they call invaria
GONZOApril 19th, 2007, 11:00 am
Site Editor
"Bear Swamp," PA

Posts: 1681
I do know a couple of biologists/entomologists that still draw a distinction between invaria and rotunda, but I don't know enough about their reasons to make their argument for them.
OldredbarnNovember 24th, 2009, 2:24 pm
Novi, MI

Posts: 2591
Lou,

I know your last post to this was a few years back, but I spotted it today and wanted to comment.

I agree with you that if this is actually E. invaria it's nowhere near hatching. On the Au Sable these bugs are a good 16 if not a tad bigger.

What I'm interested in though is your comment about color...I have heard guys like Borger speaking at fly fishing shows that color can be very important in imitations that have any part of them below the surface. It is interesting, for me, in that I sometimes think I have blinders on and get fixated on the bugs that are about to "hatch". What about this guy? He has to be available to the trout and therefore maybe worthy of imitating...What do you think?...A size 18 invaria nymph...When, in its lifecycle, would it be this size?

We need to get GONZO and Taxon to chime in here...We don't really hear too much about bugs that are immature. There is some discussions, I've read about, regarding the activity of nymphs just prior to hatching and I've read a little bit about them floating in the drift...But, I wonder, is it worthwhile trying to imitate them?

I have another question for them as well. Something has been bugging me a bit lately as I tie up someflies for next season. Here it is...When a female mayfly is at the surface about to leave its nymphal shuck are her eggs visible? Or...Do they appear after she moults in to an adult?

My question came to me when I was working on spinners and wasn't completely aware of what color to make the egg sack on females...I have seen them on some mayflies and some appear yellowish and others of an olive hue...I've seen them hanging from caddis as well...I am wondering just how important this may or may not be? I have seen patterns where it calls for the imitation of the egg sack...Do the fish really lock on to this feature???

Anyway! I need to head home for the evening...

Take Care! The things we fly fishermen contemplate! Strange, eh?

Spence

P.S. I have a Coq de Leon that has been dyed with some yellow that would match that critters tail perfectly...Lou...Are we nuts?!
"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
TaxonNovember 24th, 2009, 5:59 pm
Site Editor
Plano, TX

Posts: 1294
Spence-

A size 18 invaria nymph...When, in its lifecycle, would it be this size?


I believe Ephemerella invaria are univoltine, which means they would spend ~11 months in their nymphal livestage. The mature nymph would normally achieve 8-9 mm. in length (size #14), so it would probably have achieved ~6 mm. in length (size #18) by (perhaps) 6 to 9 weeks prior to emergence.
Roger Rohrbeck
www.FlyfishingEntomology.com
OldredbarnNovember 24th, 2009, 8:35 pm
Novi, MI

Posts: 2591
Taxon,

That couple weeks around opening day must be very crowded! Not only do we have all the action of bugs in various stages of emergence, but all these immatures crawling around...It's a wonder that our fakes get any attention at all...

You know this may account for the success of a good old Hare's Ear Nymph in a variety of sizes...We may think of it as an all-rounder or use it as a searching pattern, when it may be a fair imitation of some of these immatures...The same might be said for the Pheasant Tail Nymph as well...

With all that food crawling around it's odd that a trout would need to take anything off the surface, but we all know they do.

Thanks! Maybe you and I can start a new style of fishing. Some are tossing comparaduns, some parachutes, some nymphs, some emergers, others cripples...Some of the odder lot are still waiting for a spinner fall...But you and I wll be slaying them with our "Immatures". No longer a slave to the hatch!

We can create new charts. We won't be able any longer to call them "Hatch Charts"...Ours will list smaller sizes and we will fish flies 6-8 weeks prior to their emergence...We will fool the shit out of them trout who have become "schooled" or "educated" to all the flies from the local shops...The fish will be laughing at those old school Match the Hatchers...But we are on to them...

My new secret fly is a size 18 E invaria nymph...Don't tell anyone!

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
TaxonNovember 24th, 2009, 10:57 pm
Site Editor
Plano, TX

Posts: 1294
Hi Spence-

Certainly not intending to rain on the parade to which you have invited me, but Ephemerella invaria would not be nearly as available to trout until the mature nymphs begin (oops, I almost said migrating, but as I recall, Jason doesn't care for that term) moving to slower water. Probably, the best stage of the lifecycle to imitate, is when the nymph is still just beneath the surface, and is just beginning to break out of its nymphal shuck, as once it has escaped, under customary circumstances, they take wing rather quickly.
Roger Rohrbeck
www.FlyfishingEntomology.com
OldredbarnNovember 25th, 2009, 6:07 am
Novi, MI

Posts: 2591
Roger,

Now wait just a moment! You are a scientific type of guy and the empirical evidence isn't in yet. Besides....What an I going to do with all these size 18's I've already tied up? I'll have to get back to you after opening day 2010...

Sometimes you scientific types are a little slow to catch the punch line, but if you put on you funny hat and read my post again slowly you may see my feeble attempt at pokking fun at a sport (our sport) that actually discusses these sorts of things along with cripples, stillborns, and "migrations" of emerging bugs...

How about the semantic argument, I think it might be, of when a "migration" is or isn't a migration...? "Is it further father, or father further? Are you following me? Stop or I'll call the police!"
As Groucho use to say! You have to admit Rog, we anglers are an odd lot!

This lack of humor, or over seriousness, about our obsession may have led to what I thought was my funniest post being ignored. Maybe it just wasn't funny, but the one where I jokingly created a new species E. caverna after seeing a mayfly stuck on the end of a cave dwelling slug's sticky, spiderlike trap, surprised me...Not one response! I saw the event on a NatGeo special about life deep inside caves...Oh well! Don't quit my day job I guess.

Just this morning as I was driving in to work there was a science report on NPR about how ants find their way to and from food in the Sahara Desert...I was laughing so hard I almost put the Saab in the ditch. Turns out they count their steps!

They separated three goups of ants, only a wacky entomologist would try this one, they super glued little hairs on to the legs of one group of ants...They cut off to the knees the legs of another group, and the control group they left alone.

When the ants went home the group with the longer legs actually overshot the nest, the shorter legged ones undershot the nest and the control group got home just fine. The guy from Ulm (Deutschland...birthplace of Herr Professor Doktor Einstein)who was conducting the experiment concludes the little critters can count their steps. Funny no?!

Anyway Roger, if our concept of fishing "Immatures" (I better trade mark this) ever actually takes off, and in the next decade the dough starts to flow my way after the book deals etc, I'll say thanks to you in the foreword...Ok?

Take Care!

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
TaxonNovember 25th, 2009, 8:54 am
Site Editor
Plano, TX

Posts: 1294
Spence, Spence, Spence. My goodness, how can you fault me for having a flagging sense of humor. Trust me on this. There is a there, there. As to scientific perspective, I confess to being a pauper; just trying to hold the fort 'til Gonzo re-emerges following ski season.

As to your surplus of #18's, I do have several suggestions. You could probably dump some by joining one of those fly exchanges. But if that's not appealing, just send some my way, and I'll help you amass empirical evidence.

Best regards,
Roger Rohrbeck
www.FlyfishingEntomology.com
OldredbarnNovember 27th, 2009, 7:35 am
Novi, MI

Posts: 2591
Roger,

I stand corrected! There is some humor there...

I love to watch the show, "The Big Bang Theory", and they have the stereotyped science personality down...Maybe I have just been watching it too much.

I have a couple old friends from my high school days that when you look in the old yearbooks there is always a picture of the both of them standing with the chemistry teacher...A Mr. Lupo. There is also the one young woman in the school in the photo that probably went off to work for NASA or the NSA after she graduated.

Both my friends went off to the UP and Michigan Tech after they graduated in 1971. One eventualy graduated with honors and the other one ended up dropping out twice from Tech and once from Western Michigan U...

When the ne'er-do-well headed back up the second time my other friend kept me posted as to how the other one was doing...The letters started out with a positive tone at first and then the ones started to arrive that our friend was reading sci-fi novels again...I knew it was soon to be over again and like clockwork there would be a knock on my parent's door and there he stood....

I guess Rog that I'm just poking fun at the nerd in all us angler/junior entomologists out there...

I'll keep you posted re the "science" of immature-nymph fishing. It's funny how much hooey has been sold to us as "science"...Freud tried to explain that his method of psychoanalysis was more "scientific" as those charlatans that had gone before him...Marx called his brand of socialism, "scientific socialism"...Hmmmm.

Take Care!

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
OldredbarnNovember 30th, 2009, 10:49 am
Novi, MI

Posts: 2591
Roger,

"I'll keep you posted re the "science" of immature-nymph fishing."

A little addendum to our conversation about fishing and tying flies for "immature nymph fishing"...I am reading Eric Leiser's, "Stoneflies for the Angler" and there is a wonderful section about "behavioral drift". Others have written about this like LaFontaine in his caddis book. In Leiser's book he quotes quite a few studies that have been done in relation to behavioral drift and stoneflies...

I guess there may be some "science" to our madness after all, eh? A skilled nymph angler should clean up in that first couple hours after sunset when all these critters are floating downstream...During this time I am usually fixated on the dry fly action that also seems to be good during the same time as this drift is taking place.

Us Michigan anglers are quite attune to fishing after the sun goes down...All the big drakes and of course the Hex all tend to be after the sun goes down activity, not to mention the tendency of the various spinners who tend to fall during the "bewitching hour".

With the stoneflies it appears that they can live as a nymph for 2-3 years. So there must be various sizes available at different times of the season. Leiser mentions a study of the a baetis species that is multi-brooded and when the second eggs hatch the older, larger nymphs are the ones that seem to move.

There are also studies that show that the fish can become selective when there are different bugs available in the drift. They tend to chase after the larger bugs and will switch if a larger bug is present.

On a different topic...Leiser has a couple neat stories in there about the voraciousness of the stonefly nymphs that dine on other bugs instead of detritus. One was of a guy that used live nymphs to fish with and related a story about nymphs that would drag split-shot along on the bottom of the stream...They were this strong.

He told another one about a stonefly nymph attacking alevins and killing them...Pretty damn aggressive little buggers...

Anyway!

Take Care!

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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