Fly colours

[Otter]

Welcome Reed,

As much of this hinges on whether a trout can see UV and does indeed use UV in insect prey recognition.
Logic would say NO, if UV detection was an important factor then you would expect scientists to have a clear indication that adult trout has well developed vision in the UV range.

on a non scientific level

For starters your loose conclusion that because insects see UV and may use UV for recognition in their mating rituals this cannot be transposed onto the trout anymore than one could determine that a zebra should be a carnivore because it has teeth.

Also I would suggest that the main reason that insect activity is at night ( at least where i come from) is nought to do with UV but to do with the fact that the wind more often than not eases at dusk - this is of paramount importance to the insects, going about their lifecycle.

As I do not enjoy an indepth knowledge of these matters, I can but look at conclusions based on each ones investigations.

I have to date not seen any real evidence backed by proveable or at least logical results that would persuade me to see UV as a likely enhancement to our flies.

You may be onto something, you may be travelling a cul de sac, I know not - good luck with your investigations.

[Mike Connor]

This obviously generated quite a lot of interest, and lots of people are asking me all sorts of stuff related to it. There is no need to understand any of the complicated examples or studies given in the course of this discussion in order to dress flies or catch fish. Indeed, they are largely irrelevant. If you want to know something about the various examples given then the best way to do it is to research them on the net.

The crux of the matter here is that a scientific theory is an idea that is supported by evidence and is falsifiable* in practical tests. If an idea has no evidence but is consistent with existing theories, it is a hypothesis. If an idea is not consistent with existing theories and has no evidence, it is speculation. All these categories have roles in science, but all scientific ideas must eventually be supported by evidence.

There is no evidence here, or anywhere else, relating to positive effects of UV related factors on artificial flies. Nor are there any related practical tests. It is merely speculation based on a large number of unrelated matters and phenomena. It is interesting but it wont help you dress any better flies or catch any more fish.

* http://en.wikipedia.org/wiki/Falsifiability

TL
MC

[Roadkill]

I would just like to see a single UV photograph of 2 flies of the same color with the same lighting, one tied with UV ice dub and a copy with ordinary ice dub to see the UV effect.

[overmywaders]

Hello Otter,

Scientists have a clear indication that trout have UV vision. Even the single scientist who believes that the UV-specific cones all become blue-specific indicates, as I quoted, that without any UV-specific cones, the trout still have UV vision. That is definitive enough for me; I can only assume the trout agree.

Until fairly recently, we didn't even know that all families of diurnal birds thusfar tested would prove to have UV vision. But such is the case. And humans lacking the yellow pigments in the lens of the eye have UV vision as well. This is not a choice for them, they (aphakic humans) have it, it alters their view of the world. What does this have to do with trout? Simply that, given that trout have no retinal protection from UV, have cones that accept UV (whether UV-specific or not), have imprinted from a fry to discriminate in the UV (UV vision is their first vision) -- trout receive UV information. Now, does it behoove a fish to ignore information regarding a potential threat or a potential meal? That doesn't seem like a desirable evolutionary trait, even were it possible.

It doesn't matter why many mayflies mate at night, suffice that we agree that they do. Since they do, their UV vision has been documented as instrumental in mating. A spinner upon the water long after dusk will be seen, by a trout below, as backlit in the predominantly UV light. The UV signature of the wings of the natural will become accepted as part of the model the trout builds for a safe morsel to eat at that time. Is that a leap? Why would a fish ignore the obvious?

What would be credible proof that dry flies with proper UV markings are more successful than those lacking the markings? That was the question I posed to myself as I was writing the book. My answer was -- at least a few decades of use that showed the success of particular patterns. If these patterns exhibited UV markings consistent with the naturals, that would be cogent.

In order to get an unbiased representation
of artificial flies to test under UV, I used the
suggested dry fly assortment from the LL Bean
Fly-Fishing Handbook by Dave Whitlock
(Winchester Press, Piscataway, NJ, 1984).
Many of these fly patterns date from the 1930s
or earlier; they have stood the test of time.
Pattern lists from any later than the mid-1980s
would usually not include variants, bivisibles,
or spiders—all very effective styles. The late
1980s was also known for the beginning of
the shift to synthetics and away from natural
furs and feathers, introducing the variables of
differing material compounds, manufacturing
techniques, dye lots, etc. Following are
the 22 standard dry fly patterns for trout
recommended by Dave Whitlock. Each fly is
photographed first in VIS with a neutral background
and then in UV without a background.
By removing the background in UV there is no
reflection but that from the fl y itself, making it
easier to identify the true UVR.

taken from "The New Scientific Angling..."

Does that sound like a reasonable approach? If not, why not? All thoroughly documented (as Arlo said "with pictures and arrows, and a paragraph on the back explaining each one"). Since the natural insects - mayflies, caddis, terrestrials - were also shown in the UV, the reader could see for him/her self the similarities in markings - or absence of markings in the case of beetles.

Let me know what you think.
Thanks.

Regards,
Reed

[Mike Connor]

I would just like to see a single UV photograph of 2 flies of the same color with the same lighting, one tied with UV ice dub and a copy with ordinary ice dub to see the UV effect.

Wouldn't do you much good as what you would see is merely a technical representation. You still would not know what the fly looked like in UV light;

http://en.wikipedia.org/wiki/Ultraviolet_photography

TL
MC

[overmywaders]

roadkill,

I have the following two photos of Hareline Ice Dub, but not Ice Dub UV
Visible light


UV


Hareline will be putting notations in their next catalogue regarding the UV reflectance and UV fluorescence of many of their products. I hope that helps you.

Regards,
Reed

P.S. - I find it interesting that the gray and the light blue are much brighter in the UV than the pink. You never know...

[Mike Connor]

Hello Otter,

Scientists have a clear indication that trout have UV vision. Even the single scientist who believes that the UV-specific cones all become blue-specific indicates, as I quoted, that without any UV-specific cones, the trout still have UV vision. That is definitive enough for me; I can only assume the trout agree.

Until fairly recently, we didn't even know that all families of diurnal birds thusfar tested would prove to have UV vision. But such is the case. And humans lacking the yellow pigments in the lens of the eye have UV vision as well. This is not a choice for them, they (aphakic humans) have it, it alters their view of the world. What does this have to do with trout? Simply that, given that trout have no retinal protection from UV, have cones that accept UV (whether UV-specific or not), have imprinted from a fry to discriminate in the UV (UV vision is their first vision) -- trout receive UV information. Now, does it behoove a fish to ignore information regarding a potential threat or a potential meal? That doesn't seem like a desirable evolutionary trait, even were it possible.

It doesn't matter why many mayflies mate at night, suffice that we agree that they do. Since they do, their UV vision has been documented as instrumental in mating. A spinner upon the water long after dusk will be seen, by a trout below, as backlit in the predominantly UV light. The UV signature of the wings of the natural will become accepted as part of the model the trout builds for a safe morsel to eat at that time. Is that a leap? Why would a fish ignore the obvious?

What would be credible proof that dry flies with proper UV markings are more successful than those lacking the markings? That was the question I posed to myself as I was writing the book. My answer was -- at least a few decades of use that showed the success of particular patterns. If these patterns exhibited UV markings consistent with the naturals, that would be cogent.

In order to get an unbiased representation
of artificial flies to test under UV, I used the
suggested dry fly assortment from the LL Bean
Fly-Fishing Handbook by Dave Whitlock
(Winchester Press, Piscataway, NJ, 1984).
Many of these fly patterns date from the 1930s
or earlier; they have stood the test of time.
Pattern lists from any later than the mid-1980s
would usually not include variants, bivisibles,
or spiders—all very effective styles. The late
1980s was also known for the beginning of
the shift to synthetics and away from natural
furs and feathers, introducing the variables of
differing material compounds, manufacturing
techniques, dye lots, etc. Following are
the 22 standard dry fly patterns for trout
recommended by Dave Whitlock. Each fly is
photographed first in VIS with a neutral background
and then in UV without a background.
By removing the background in UV there is no
reflection but that from the fl y itself, making it
easier to identify the true UVR.

taken from "The New Scientific Angling..."

Does that sound like a reasonable approach? If not, why not? All thoroughly documented (as Arlo said "with pictures and arrows, and a paragraph on the back explaining each one"). Since the natural insects - mayflies, caddis, terrestrials - were also shown in the UV, the reader could see for him/her self the similarities in markings - or absence of markings in the case of beetles.

Let me know what you think.
Thanks.

Regards,
Reed

Just more speculation. Without evidence that these things are connected, you are just wasting your time.

The only credible proof would be if a fly designed according to your specifications caught better than some other fly in the same circumstances.

Everything else is irrelevant.

TL
MC

[overmywaders]

Mike,

You said:

The only credible proof would be if a fly designed according to your specifications caught better than some other fly in the same circumstances.

I refer you to the words of the sage:

This is another point which is relevant to this discussion. Assuming that these UV factors play a part in the design, selection, and use of artificial flies. It can not be a major or essential part, or all the flies which have been designed and work extremely well to date, without these factors being known, either work independently of these theories, are coincidentally in accord with these theories, or the theories are wrong or irrelevant.

Well, Mike, if we look at the fact that the 22 fly patterns were all those deemed most effective by a very knowledgeable fisherman/author in 1984, had many years/decades of use, and are "coincidentally in accord with these theories"; then I guess the significant criteria are satisfied. Unless you disagree with the quote from the sage above, of course.

[overmywaders]

Anyway, it appears that we have exhausted the discussion of UV vision in trout. Rather, I enjoy discussing this fascinating subject, but I am exhausted.
I hope you all have a great season, it is 70+ degrees outside in NH; Spring approaches.

All the best,
Reed

[Mike Connor]

Mike,

You said:

The only credible proof would be if a fly designed according to your specifications caught better than some other fly in the same circumstances.

I refer you to the words of the sage:

This is another point which is relevant to this discussion. Assuming that these UV factors play a part in the design, selection, and use of artificial flies. It can not be a major or essential part, or all the flies which have been designed and work extremely well to date, without these factors being known, either work independently of these theories, are coincidentally in accord with these theories, or the theories are wrong or irrelevant.

Well, Mike, if we look at the fact that the 22 fly patterns were all those deemed most effective by a very knowledgeable fisherman/author in 1984, had many years/decades of use, and are "coincidentally in accord with these theories"; then I guess the significant criteria are satisfied. Unless you disagree with the quote from the sage above, of course.

I have said all I am going to say on the matter. If you refuse to accept recognised scientific procedure, or even basic logic and common sense, there is very little point in discussing anything at all with you. The more words you waste on wriggling and trying to confuse the issue the more ludicrous it appears.

I don't care who deems what, or how you attempt to tangle the matter up with more irrelevancies, simply because you are either unable or unwilling to accept the simple truth, that is your problem not mine.

You are the one propounding this speculation. If you want to turn it into a workable theory then you need proof. You have none.

That's all there is to it.

Either come up with some proof or stop misleading people.

TL
MC