Troutnut.com Fly Fishing for Trout Home
User Password
or register.
Scientific name search:

> > Subsurface mayfly emergence: a conflicting account from one book

TroutnutJuly 3rd, 2006, 3:11 pm
Administrator
Bellevue, WA

Posts: 2541
I'm just reading through Ted Fauceglia's book Mayflies. (The pictures are great, for those who haven't bought it. Anyone who likes this site will like that book.)

One interesting thing I've noticed is Ted's description of the emergence of species like Epeorus pleuralis and Attenella attenuata which are usually said to emerge on the bottom of the stream and float to the surface as duns. Ted writes that they begin to emerge on the bottom but rise to the surface before they've fully left the nymphal shuck, and struggle free during their rise.

This seems less plausible, in addition to contradicting earlier books. I'm wondering if he's basing it on new entomological information, or if it's just a misinterpretation of what past books have said. Does anyone know?
Jason Neuswanger, Ph.D.
Troutnut and salmonid ecologist
TaxonJuly 3rd, 2006, 8:24 pm
Site Editor
Plano, TX

Posts: 1294
Jason-

Hafele/Hughes have the following to say about the subject in their recently (2004) published book, Western Mayfly Hatches:

"Some Epeorus and Ironodes rise to the surface as duns, buoyed up by gases trapped in the folds of the wings. Others rise as nymphs, buoyed to the surface by a bubble of gas that forms under the cuticle. Those that rise as nymphs emerge into the dun stage in the surface film. They are efficient emergers, and very few are crippled in the process."

I realize this doesn't answer your question about emergence behavior of a particular species, Epeorus pleuralis, which we don't have in the West, but am sharing it with you anyway, assuming you may not have ready access to the book.
Roger Rohrbeck
www.FlyfishingEntomology.com
TroutnutJuly 3rd, 2006, 10:11 pm
Administrator
Bellevue, WA

Posts: 2541
Thanks Roger. You guessed correctly -- I don't have that book yet. What they wrote echoes what I've seen in every other book about the eastern hatches.

This book has one strange description for several species: that the emergence takes place neither at the surface nor on the bottom, but during the rise up to the surface.

I'm guessing it's just an error, but since it is the most recent work published on mayflies I thought I'd see if there's more to it.
Jason Neuswanger, Ph.D.
Troutnut and salmonid ecologist
TroutnutJuly 4th, 2006, 8:31 am
Administrator
Bellevue, WA

Posts: 2541
Here's something that might answer the question, from Malcolm & Knopp's Mayflies:

The duns may emerge while the nymphs remain attached to the riverbed (moderate- to fast-water dwelling species such as E. pleuralis) or while rising to the surface film (slow-water-dwelling species).


So maybe the "hatching while rising" thing happens for some species and replaces the behavior of hatching at the surface.
Jason Neuswanger, Ph.D.
Troutnut and salmonid ecologist
TaxonJuly 4th, 2006, 3:36 pm
Site Editor
Plano, TX

Posts: 1294
Jason-

Makes sense to me.
Roger Rohrbeck
www.FlyfishingEntomology.com
GONZOSeptember 12th, 2006, 3:57 pm
Site Editor
"Bear Swamp," PA

Posts: 1681
Just thought I'd chime in on this one, for what it's worth. My impression is that there's a certain amount of flexibility with regard to methods of emergence for many species. While they may have a "preferred" method of emergence, alternatives serve as a kind of adaptive safety valve to insure survival under atypical conditions (floods, drought). Even under relatively "normal" conditions, a few specimens may display less typical methods of emergence. This seems to be rather well-documented for Isonychia and Siphlonurus (terrestrial or aquatic emergence); but many species in such diverse genera as Drunella, Ephemerella, Epeorus, and Maccaffertium also display such flexibility at times. For example, I have watched a march brown nymph (M. vicarium) crawl out on a rock and emerge successfully in typical stonefly fashion! While I'm sure that this behavior is quite unusual for this species (I've never seen it documented), it does serve to demonstrate this flexibility. So, it seems quite plausible that some species of Epeorus might emerge on the bottom, on the surface, or somewhere in between. My only quibble with the Knopp (Mayflies) information on Epeorus emergence is the description of E. vitreus (yellow quill) as a slow water dweller. That does not match my experience with this species.
SofthackleOctober 31st, 2006, 5:30 am
Site Editor
Wellsville, NY

Posts: 540
This is probably a bit off the subject, but I've yet to see any definative proof that "flies rise to the surface on a bubble of air".I do not disagree that flies do fully hatch underwater, and come to the surface, However, I have not seen proof of the air bubble. Jason, if you've got some pictures that illustrate this phenomenon, I'd love to see them.

Mark
"I have the highest respect for the skilled wet-fly fisherman, as he has mastered an art of very great difficulty." Edward R. Hewitt

Flymphs, Soft-hackles and Spiders: http://www.troutnut.com/libstudio/FS&S/index.html

Quick Reply

You have to be logged in to post on the forum. It's this easy:
Username:          Email:

Password:    Confirm Password:

I am at least 13 years old and agree to the rules.

Related Discussions

TitleRepliesLast Reply
Re: Thoughts on this Heptageniid's ID?
In Male Epeorus vitreus Mayfly Dun by Troutnut
1Oct 28, 2008
by GONZO
Re: Today's exam
In General Discussion by Kroil
13Mar 8, 2008
by Ducfat
Re: confusing fish behavior
In General Discussion by Wwelz
2Jun 26, 2008
by Wwelz
Re: Updates on learning the "Gonzo" style nymphs.......
In Fly Tying by Bjanzen
3Nov 19, 2006
by GONZO
Re: It is darker than most
In Male Ephemerella excrucians Mayfly Dun by Brookyman
8Apr 8, 2013
by Brookyman
Re: Name that hatch?
In General Discussion by Rbpcaddis
1Jul 13, 2007
by Taxon
Re: Banksiola
In the Caddisfly Genus Banksiola by Entoman
4Jan 22, 2011
by Entoman
Re: Stonefly, very dark but what else can I find out?
In Isoperla Stonefly Adult by IanB
1May 5, 2009
by GONZO
Re: Western Catskills 2007 - 2012
(1 more)

In the Photography Board by Wbranch
10Jan 9, 2013
by Entoman
Re: Great Autumn Brown Sedges on Potomac River
In the Caddisfly Genus Pycnopsyche by BrettB
3Oct 3, 2008
by GONZO
Most Recent Posts
6wt reel help
In Gear Talk by Swampfox
Re: Boots
In Gear Talk by Martinlf (Wbranch replied)
Re: nm
In Gear Talk by Red_green_h
Re: My (new) place and its environs
In the Photography Board by Jmd123 (Partsman replied)
Re: Holy Waters - over-rated
In General Discussion by Brian314 (Partsman replied)
Re: Cold weather fly fishing
In Beginner Help by Red_green_h
Re: Site updates from September 11, 2019
In Site Updates by Troutnut (Martinlf replied)
Re: Fly fishing Basque Country in Spain
In General Discussion by 87Defender (Wbranch replied)
Re: Spain? Rules, licenses and such?
In General Discussion by Shanti (Martinlf replied)