Pretentious Snobby Bastard Fly Fishing!

Fly Fishing BS => The Gravel Bar => Topic started by: The Dude on December 09, 2010, 20:00:01 PM

Title: Post from another board
Post by: The Dude on December 09, 2010, 20:00:01 PM
I saw this post on another board and was interested in seeing the discussion on it.  As it turns out, there wasn't much in the way of discussion generated on that board.  So, after getting permission from the original poster, I'd like to post it here and see what the trout brains on this board had to say about it.  Here is the meat of the post:

"What is the reason for a mayfly nymph metamorphing from the dun into a spinner???

In other words, I understand the need for an emergence from the nymphal stage to the adult stage. The bug is changing from an underwater environment where it needs to have gills, a flat profile, legs that can cling to rocks in current, a head that can burrow and dig and a mouth that can break down detritus and other food sources. And, as an adult, the bug takes to the air and requires wings to fly and mate, an abdomen with tails for procreation and ovipositing of eggs, etc. Mechanically, the bug needs to change forms.

But, what happens between the dun and spinner phase? It seems that the dun stage is superfluous to me. Why not just go right from nymph to spinner?"
Title: Re: Post from another board
Post by: ajhock on December 09, 2010, 20:22:47 PM
"But, what happens between the dun and spinner phase"  The proverbial and literal "shooting of the wad".   
Title: Re: Post from another board
Post by: Trout Maharishi on December 09, 2010, 20:41:32 PM
Sexual maturity :;!
Title: Re: Post from another board
Post by: jwgnc on December 09, 2010, 21:17:27 PM
Duns are cool looking flies, and look like sailboats, so photographers focus on them, and fly fishers have tied loads of them.  If all those flies were wasted, the economy would suffer.

And while the duns are on the water, the males and females check each other out and exchange phone numbers for later.  Kinda like the boaters on Lake Norman.  While the bugs are distracting the vicarious trout, vicarious fly fishers can catch them with almost no skill at all in what is called matching the hatch.  (that's when I do my best) Most fly fishing books are written about the hatch because it makes a better film if your book gets made into a movie.

Also, if there weren't duns we would have to drink beer from what would be the hatch until the spinner fall and by then we'd be drunk and disorderly.

Can you repeat the question?
Title: Re: Post from another board
Post by: trouthemp on December 09, 2010, 21:36:14 PM
I'm sexually aroused......is this normal?
Title: Re: Post from another board
Post by: Trout Maharishi on December 09, 2010, 21:46:28 PM
Quote from: trouthemp on December 09, 2010, 21:36:14 PM
I'm sexually aroused......is this normal?

Not according to your wife ;D
Title: Re: Post from another board
Post by: troutphisher on December 09, 2010, 22:17:54 PM
Le-me guess....."another board".........

This must be from the braniacs on the SELFFF.......
Title: Re: Post from another board
Post by: bugman on December 10, 2010, 08:38:39 AM
I knew it!  This is what happens when you drink beer and hit the ganja.  The result is some weird sensations, like arousal from a discussion of something as simple and pure as the mayfly life cycle.

I also saw this question on another forum.  And I think the gentleman that asked is a good egg; he seems interested in critters and appears inquisitive.

You must admit it is an interesting question.  TM is spot-on; sexual maturity occurs between the dun and spinner.  The "shooting of the wad" happens between spinner and death, if the mayfly is lucky.

You all know that the mayflies are low on the evolutionary scale.  I think fossil records indicate that ancient mayflies had more than 1 dun stage and these ancient duns likely fed, unlike present-day duns that do not feed and have 1 stage.  The consensus is there has not been enough selective evolutionary pressure on the mayflies to eliminate the dun stage.  There is also a theory that flight in mayflies developed before the development of suitable terrestrial reproductive structures.  So, the mayflies learned to fly before they learned how to screw in the terrestrial world, making the dun a valuable stage in exploiting another niche.

Title: Re: Post from another board
Post by: Beetle on December 10, 2010, 08:48:33 AM
Bugman, you mentioned to me one time that the duns grow larger after emerging from the water.   Tails get longer and the body grows by a few segments.   Does this growth affect/effect the secondary molt?   Apologize in advance for the elementary question(s).

Also- Will has decided that he might try to do Evolution of the Mayfly for his school science project....you will get a call!   'c;
Title: Re: Post from another board
Post by: bugman on December 10, 2010, 09:27:43 AM
John, they really don't grow, they expand.  The tails, that appear atrophied when the dun first hatches, will straighten, and the body will expand shortly after emerging from the water, making the critter appear a bit larger than before.  And the color will change slightly after the hardening of the new and expanded exoskeleton.  This expansion and hardening occurs after every molt.  The simple process of molting is one of the reasons insects are so successful and abundant.

Master Will will get all the help he needs on his science project!  Call anytime.   
Title: Re: Post from another board
Post by: The Dude on December 10, 2010, 10:09:23 AM
Do the wings of the spinner develop inside the body of the dun and unfurl during the final metamorphasis?  As such, can you tell an appreciable difference in the body of a dun when it has freshly emerged from the nymphal stage as compared to when it is just about to metamorph from dun to spinner, by virtue of a bulging wingcase?
Title: Re: Post from another board
Post by: Leedawg on December 10, 2010, 10:23:18 AM
Im no educated man like bugman, but if you hang around the river and watch a major hatch throughout.. It appears to me that most of the bugs land back on the water and then slowly give up. I have seen spinner falls where the bugs are "spent" meaning wings flat out to the sides and flat on the water, when they hit the water. I I have also seen others where the "duns' with upright wings land on the water as sailboats then they slowly kill over and they appear to be somewhat "cripples" during this time. Good question as far as I'm concerned
Title: Re: Post from another board
Post by: bugman on December 10, 2010, 10:27:17 AM
CC - The entire spinner is developing inside the dun exoskeleton.  As I said above, there are very slight changes in the dun from the time of leaving the water till it molts that last time to a spinner.  But there is no "wingcase" in the duns, because the duns have functional wings.
Title: Re: Post from another board
Post by: Leedawg on December 10, 2010, 10:33:31 AM
Bugman. Do you have any theories on why the spinner fall is happening during daylight hours on the SoHo now? In years past it mostly happened after dark. It was pretty perplexing this year a couple times with emergence of fresh duns mixed with spinners? Fun working the problem though!
Title: Re: Post from another board
Post by: bugman on December 10, 2010, 10:51:16 AM
I am sorry Leedawg; I don't have a clue.  I did see more spinner falls this year on the SoHo, BUT I only fished the same short section for most of the year.  Historically, the only time I would see spinners were in the puddles near the river and on the river surface early in the morning.  And they were dead from doing their thing during the night.  This year I saw more towards evening, doing what they do, then ending up on the surface, before total darkness.
Title: Re: Post from another board
Post by: Silver Creek on December 10, 2010, 11:57:45 AM
Quote from: CC Rider on December 09, 2010, 20:00:01 PM
I saw this post on another board and was interested in seeing the discussion on it.  As it turns out, there wasn't much in the way of discussion generated on that board.  So, after getting permission from the original poster, I'd like to post it here and see what the trout brains on this board had to say about it.  Here is the meat of the post:

"What is the reason for a mayfly nymph metamorphing from the dun into a spinner???

In other words, I understand the need for an emergence from the nymphal stage to the adult stage. The bug is changing from an underwater environment where it needs to have gills, a flat profile, legs that can cling to rocks in current, a head that can burrow and dig and a mouth that can break down detritus and other food sources. And, as an adult, the bug takes to the air and requires wings to fly and mate, an abdomen with tails for procreation and ovipositing of eggs, etc. Mechanically, the bug needs to change forms.

But, what happens between the dun and spinner phase? It seems that the dun stage is superfluous to me. Why not just go right from nymph to spinner?"

The "hatch" from nymph to subimago (dun) happens over hours during the day. The change from subimago (dun) to imago (spinner) does allow the species to coordinate the mating flight so that the subimagos that hatched over many hours can now gather to mate over a shorter time. I suspect this increases the probablity of the short lived female imago's eggs being fertilized.

Mayflies are lest robust than stoneflies and caddis and die shortly after emerging. Therfore, coordinating mating by the subimago to imago phase is a survival advantage.

http://insects.tamu.edu/fieldguide/aimg3.html (http://insects.tamu.edu/fieldguide/aimg3.html)

"Adult mayflies are very short lived, surviving only one or two nights. During that time the adults mate in swarms in the air."

http://www.delawareriverguide.net/insects/caddisflycyc.html (http://www.delawareriverguide.net/insects/caddisflycyc.html)

"Unlike Mayflies after ovipositing adult Caddisflies don't die right away, but fly off to live for a varying length of time."

http://en.wikipedia.org/wiki/Plecoptera (http://en.wikipedia.org/wiki/Plecoptera)

"The adults generally only survive for a few weeks, and emerge only during specific times of the year"

Caddis and stoneflies have mass hatches in which the adults emerge over a shorter time. Mayfly hatches last weeks and sometimes even longer than a month. For the "Salmon fly" stone fly hatch on the Madison, the hatch in a given area last only a day or so, hence the fly fishers travel with the hatch up river.


http://en.wikipedia.org/wiki/Caddisfly (http://en.wikipedia.org/wiki/Caddisfly)

" In common with many aquatic insect species, many caddisfly adults emerge synchronously en masse. Such emergence patterns ensure that most caddisflies will encounter a member of the opposite sex in a timely fashion."
Title: Re: Post from another board
Post by: Leedawg on December 10, 2010, 13:11:48 PM
We haunted the exact same section of river you did this year and this is the first year I have ever seen emergers, duns, and spinners on the water in the afternoon. Fun fishin!
Title: Re: Post from another board
Post by: The Dude on December 10, 2010, 14:32:43 PM
Quote from: bugman on December 10, 2010, 10:27:17 AM
CC - The entire spinner is developing inside the dun exoskeleton.  As I said above, there are very slight changes in the dun from the time of leaving the water till it molts that last time to a spinner.  But there is no "wingcase" in the duns, because the duns have functional wings.

Thank you for the response, but I have a couple of other questions to help me clarify.  The spinner wings do not develop sheathed within the dun wings, right?  In other words, the spinner wings develop inside of the main body exoskeleton and not inside of the dun wings.  Not that it really matters, but I also wonder the same for legs.  Are the dun legs essentially hollow and the legs of the spinner fit inside them like a foot inside of a sock?  Or, are the legs developing separately, all squished up inside the torso and then finally stretch out once emerged?  That is why I was wondering about a possible wingcase-like bulge in a late term dun.  It's like within the normal torso section of the bug there is a new torso, plus a clump of new legs, plus a clump of new wings all bunched in there. 

The next logical question is, how much of the spinner actually develops post-dun emergence.  If a mayfly were to emerge from the nymph and only survive a day or two as a dun, then developing an entire new body inside of the dun exoskeleton represents an MAJOR growth in a really short time (I'd think you could almost watch the spinner grow inside and visibly see appendages growing.)  Or, does the spinner develop inside of the dun inside of the nymph (with the exception of the genitals)?  Theoretically, if one were to catch a nymph just prior to emergence, and you could somehow peel away layers of skin like an onion, would you be able to peel off the nymph shuck to expose the dun and then peel off the dun shuck to expose the spinner (sans genitals)?  If so, then I do agree that the dun stage is kind of unnecessary.  Maybe the genitals need to develop safely tucked in under the dun shuck, but if I was a mayfly, I'd rather skip dun and let my junx grow commando style. 

Okay, last question on this subject before I beat it into the ground completely:  If the dun stage is used as an opportunity to line up the proverbial piece of ass so that the bugs can immediately get down to business once they molt into sexually active adults, mating takes place in air, and the bugs essentially have nothing to do but die after they do their thing, then why does nature even bother expending the energy to grow legs for the spinner?  It seems like they don't really have a use for them?
Title: Re: Post from another board
Post by: bugman on December 10, 2010, 16:08:26 PM
CC – Here are a couple of links that, I think, will answer your questions much, much better than I can.  The Edmunds and McCafferty article is a classic. 

http://www.famu.org/mayfly/pubs/pub_e/pubedmundsg1988p509.pdf (http://www.famu.org/mayfly/pubs/pub_e/pubedmundsg1988p509.pdf)

http://people.uleth.ca/~dan.johnson/subimago.htm (http://people.uleth.ca/~dan.johnson/subimago.htm)


I think your question about the usefulness of legs is even addressed in the first article.

Your questions are all interesting. 

Another tidbit, related to the legs on spinners – those of you that have seen the famous White Fly (Ephoron leukon) hatch, perhaps have seen the nonfunctional legs on the females.  I've only seen the hatch once and that was years ago in PA – loved the hatch and fishing but didn't enjoy fighting for a spot to cast. 

Title: Re: Post from another board
Post by: Leedawg on December 14, 2010, 13:27:25 PM
Wow. Thanks for the info overload Bugman. Great articles! Thanks!!