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silvertip8k 05-18-2013 06:52 AM

need help with some bug terms...and anatomy differences
Hello...I know there are folks here that have a good understanding of this all. I am trying to learn what the actual physical diffecences there are between a "Dun" and a "Spinner" of various may flies.

I understand that the Dun, when it moults becomes a Spinner...I think in most cases. This is where I get confused...the "so called" still born pattern is I would think when a nymph is turning into a dun...and gets stuck...but recently I read about this being between dun & spinner??? when it is moulting its case. probably really does not matter, however in my quest to tie better and more accurately, I wanted to make an addition to the"trilogy" I tied up...and maybe add part 4...but I am not sure if the spinner is sufficiently different...are they the only ones laying eggs? and if so what ddifferences do they display...this is where my own seining and observations run out of relevance, as far as answering this.

I know this is probably old hat to many here...but I have been wandering around this all a long time...and maybe some others could learn least I know I would very much appreciate some advice...

all the best...ted

ghocevar 05-18-2013 07:07 AM

need help with some bug terms...and anatomy differences
I'll try to help out here...I am sure others will have more input for you as well, but from what I have learned is that the Mayfly has 2 adult stages; the Dun (which is after emergence and before mating) and the Spinner (after mating and on it's way out). Dun wings are opaque, while the Spinner wings are transparent.

When you are tying the spinner wings, they are supposed to lay flat on the water

tbum2020 05-18-2013 07:15 AM

Re: need help with some bug terms...and anatomy differences
Spinners are those which have reached full maturity, they will be larger and the only ones who mate and lay eggs. The difference physically is all about size, when a dun molts it's now larger and sheds a smaller exoskeleton revealing a newly developed larger exoskeleton.

Rip Tide 05-18-2013 07:46 AM

Re: need help with some bug terms...and anatomy differences
I think that you're over thinking this ..

If you want to tie up some spinners with egg cases, a little yellow ball of dubbing at the tip of the abdomen will take care of that.

As for "defective" molting duns? You could try a trailing shuck of zelon or antron or even a little wisp of nylon panty hose :rolleyes:. Maybe with one wing up-right and one rolled, stunted or horizontal.
Just having some scissors to cut your normal dun imitation down is probably the best way to go rather than tie up something special

tbum2020 05-18-2013 11:03 AM

Re: need help with some bug terms...and anatomy differences
This page should aid in any confusion, it provides an illustrated example of a Mayfly Dun to Spinner,
Mayfly Dun to Spinner Illustrated

stenacron 05-18-2013 11:27 AM

Re: need help with some bug terms...and anatomy differences
Add another one to your "must have" library Ted... Hatches II by Al Caucci and Bob Nastasi. ;)

The short answer is that freshly-hatched duns (subimago's) have clouded wings and freshly-moulted spinners (imago's) have clear wings... The long answer is that every mayfly species is different and so are their hatching/moulting/mating/egg-laying habits. It can be very confusing and there is no substitute for a good reference book to fall back on. The above title is the most comprehensive that I've seen on mayflies coast-to-coast.

Another thing to do is grab a couple duns as they're hatching and place them in a large jar (mason jars work well). Most species will molt into adult spinners within 24 hours. This way you'll see the color changes in some species between dun and spinner, and also the color/size differences between males and females of the same species (but not all species).

Pay close attention to spinnerfalls... when you see the egg-laiden females yo-yo dancing over the riffles... catch one, tie on a matching imitation, light up your cigar, and head down to the tailout of the next hole and watch for sippers. In my experience these are are sometimes the largest and wisest trout and will be taking spent spinners in the film right before the hole spills over into the next set of riffles.

trout champ 05-18-2013 11:27 AM

Re: need help with some bug terms...and anatomy differences

First of your rods and nets are works of art. I am saving my pennies for a bamboo rod.

Next, check out this link.

I have understood that after emerging, the insect sitting on the water is a dun. They are waiting for heir wings to dry off, or the rest of their shuck to come off, or have some kind of retardation and become cripples.

If they are lucky enough to make it without being eaten, they turn into duns to mate. I have been taught that they go through a color change and their wings turn white or clear. They fly off into the air to do their thing. The females return to the water to lay eggs and then die. The males die after mating and create the spinner fall.

I will use tricos as my example. For a trico dun I would tie three microfibbet split tails, black dubbed body with light or dark dun colored hackle. For a cripple I use white Widows Web with a black body and light or dark dun colored hackle. All tied in sizes 20-26.

For spinners I tie females a glossy dark green with three microfibbet tails and white hackle. I sometimes put a small (very small) dubbing ball on the back end as an eggs sack. Usually light yellow or cream colored. For spinner males I use three microfibbet tails, black body, and white fluro fibre wings tied straight out from the body so they lay flat on the waters surface.

Hope my examples help

silvertip8k 05-18-2013 03:09 PM

Re: need help with some bug terms...and anatomy differences
this joint is faster than the drive thru lane at micky dees!

rather than PM ing everyone I will just say thanks to all...a good spirit in this area for sure! I think the best insight I have from this so far is to tie an adult like the one in the pic...but lay its wings out flat?? does that sound like a good destination for that pattern?

the trout nut site pics are incredible by the way...something that can really get the creative juices flowing...

some properly trimmed flanks feathers could make a good copy I think...this is something I think can be done pretty easily...maybe segment the tail/abdomen section a bit with a light colored thread...and make the sprigs more prominent. I know some species have two and others three...(do they count good?? the bugs that is??)

I appreciate the response from all...and tolerating the ...well lets just say the lack of bugology...I did get the dun /spinner thing right at least...LOL...

also thanks for the remarks about my stuff...

I would love to see some ties by anyone else who has taken on this project too...nothing like copying some greatest hits from others to make a new pattern a success!

I think the outstretched wings done right would lay on the water perfect...if I use a hackle and clip off the bottom(at 4 o'clock to 8 o'clock) it will almost have to sit in the right position...and boy what a shadow or projection that will make...I am using this pic of a simpler pattern for an example of what it could look like...just add the bigger wings laid out flat w/ the proper shape......

all the best...t

greg_h 08-01-2013 06:16 PM

Re: need help with some bug terms...and anatomy differences

Originally Posted by silvertip8k (Post 557044)
I understand that the Dun, when it moults becomes a Spinner..but recently I read about this being between dun & spinner??? when it is moulting its case.

When the nymph emerges the fly on the water is a dun, with dull patterned wings (often 'dun' coloured, yellowish or mottled). This bug then flies to the surrounding brush to rest for about 24 hours to molt into a 'spinner' which has clear wings - and often a rust body, or at least a body with some rust colour.
If a dun was trapped (crippled) when molting to a spinner it would never make it to the river - so imitation is pointless.
After mating the males die quickly and fall to the water, and the females die once they lay their eggs into the water. In both cased the spinners lay flat on the water with wing outstretched. Since the wings are clear, the best imitation is to use white hackle (cut top and bottom) or some organza or Z-lon spread out to the side (and not too much of it). A parachute fly is also an OK substitute. The bodies are thinner than before mating, and as mentioned above are often rust or dull burgundy.
Spinners fly upstream to mate and lay eggs. A few years ago on the Farmington in Conn. I fished the emergers of the day in the afternoon in the mittle of the pool, and then it went quiet. About 1/2 later the rises were all at the head of the pool. It took a few minutes to realize the rises were to the spinners washing down from upstream.

kglissmeyer1 08-01-2013 07:20 PM

Re: need help with some bug terms...and anatomy differences
Good answers from all. While I'm not an expert, I too had this question many years ago and did my research to figure it out.

As has been said, when a nymph either rises to the surface film to emerge through the film or crawl out to shoreline vegetation to emerge the same thing happens as they split their exoskeleton and crawl out through the top of it.

This stage is the dun or "subimago" and the adults are dull and muted in colors (usually) and the wings are opaque with many being a dun color. These adults are not sexually mature and require a further moult in order to be able to mate and lay eggs to continue the survival of the species. Many good patterns for duns utilize an attached "shuck" representing the exoskeleton as it slides down the abdomen of the adult dun. I usually fish an emergence with an emerger pattern with a shuck, and a trailing nymph in a pattern of whatever is emerging at the time.

The moult occurs when the dun (subimago) flies stream-side and affixes itself onto something solid such as a branch, boulder or even the side of a building (I've had them moult on my waders). The sexually adept adult or spinner crawls from the split exoskeleton exactly as the dun emerged from the nymphal exoskeleton or "shuck". This stage is known as the "imago". The spinners are usually more defined in color and have transparent wings. Some species such as the callibaetis mayflies have spots on their wings in both the dun and spinner stages. I have never noticed that the spinner or imago stage is any larger than the dun stage. In fact it appears that the male spinners of Pale morning Duns (PMD's) out west are usually imitated best with a size 18 rusty spinner pattern, while the females are represented best in a size 16 pale olive spinner pattern. As duns or subimago they were both the pale olive or yellow that earned these mayflies the common name of Pale Morning Dun, and they are usually a size 16 for most if not all emerging duns. I'm sure regionally that this could be different.

The spinner (imago) then takes to the air for mating and egg-laying. The spinners usually move upstream as they dance up and down in the air, where they seek a mate. After mating in the air the males fall to the water as "spent" spinners, while the females drop to the water, deposit their eggs through the surface film and then also spread their wings in a spent manner and die. Most "spinner falls" seem to occur in the later evening or early morning hours. PMD's usually in the evening and Tricos in the early morning hours. For me and my tired eyes it is usually requisite that I trail my spinner imitation from a more visible dry fly - I usually use a Parasol Emerger in a pattern of whatever insect is prevalent on the water at the time.

Several years ago, while fishing Idaho's Teton River just west of the town of Driggs, I found myself in the middle of a blanket caddis emergence. Caddis were in the air and moving upstream so thick that it was impossible to breath without swallowing several. Even breathing through your nose had some disastrous results! I immediately attached a caddis pattern in matching size and color and went fishless for about half an hour while good fish were rising all around me. I took a closer look and realized that there were both male (rusty) and female (olive) PMD spinner mayflies on the water and they were what the fish were taking, despite the mass emergence of a much larger prey. The rusty spinners were size 18 and the olive spinners were 16's. I tried both sizes and found the fish were keying on the size 18 rusty spinners. In the midst of a blanket caddisfly emergence, with an amazing spinner fall in progress, the fish were targeting the smallest bugs on the water. What a blast I had when I figured it out. Oh, I forgot to say that the dozen fish I brought to hand with another dozen lost and at least that many misses, they were all whitefish feeding on the surface - not one trout in the bunch!

While the adult stages of mayflies is very short, it appears their only purpose is to emerge, moult, mate, lay eggs and die (oh, yes, AND to provide food for those fish we so truly love to catch!). Mayflies have no mouth-parts so they are unable to eat or drink in their adult stages.

Lastly, sometimes the dun or subimago gets stuck in the exoskeleton and becomes what we anglers call a cripple. There are many good patterns to imitate crippled mayflies.

Yesterday, while fishing one of my favorite local stillwaters, I experienced off-the-hook action on spinner callibaetis mayflies (more commonly known as speckled spinners) as large cruising trout fed upon the numerous victims floating spent on the water. This occurred in late morning into early afternoon.

It was unnerving to watch as 20-plus inch trout did a head-dorsal-tail rise to hungrily slurp in the hapless mayflies littering the surface of the water. It was also quite entertaining to watch as porpoising trout appeared all over the lake gorging themselves. The trick was to have the exact imitation in size and color and to time your casts to land ahead of the cruising fish. Sometimes it worked and you were rewarded with a battle royal, while others were a swing and a miss. A lot of action for about two hours straight. Some misses were so dramatic I was sure I'd have a heart attack right there!

I hope this adds to the confusion (or not) and is based solely upon my experience as an angler and fly tyer.


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