Tail end of the Pmd hatch

....got a few new photos, from Saturday, of the tail end
of the Pmd hatch on the spring creeks near Livingston, MT.
One of the things I noticed was how remarkably yellow these
little mayflies look at a distance, and how much greener
and grayer they look close up.

http://montana-riverboats.com/Pages/.../RealBugs.html

pittendrigh wrote:
...got a few new photos, from Saturday, of the tail end
of the Pmd hatch on the spring creeks near Livingston, MT.
One of the things I noticed was how remarkably yellow these
little mayflies look at a distance, and how much greener
and grayer they look close up.

http://montana-riverboats.com/Pages/.../RealBugs.html

Awhile ago the question of color of flies came up in ROFF. Some people
(including me) thought that fish would likely see colors very
differently from people. Others (rdean, for example) thought that there
would be a one-to-one relationship between the colors fish see and the
colors fish see, so it wouldn't matter.

There was an interesting article in Scientific American a couple of
months ago that's relevant.

Humans have three types of "cones," the color-sensitive receptors in the
retina. More "primitive" vertebrate species (reptiles, birds, and
presumably fish) have four types of cones, with their sensitivity
extending well into the UV (ultraviolet) part of the spectrum.

Most mammals have only two types of cones. Mammals hypothetically lost
part of their variety of cone receptors during a long period of
evolution when they were primarily nocturnal, when color perception was
unimportant, and when sensitivity to brightness was of paramount importance.

Primates (including humans) apparently re-evolved a third type of cone
(toward the blue end of the spectrum), probably because they had to
distinguish between different types of ripe fruit.

Nevertheless, human color perception is presumptively impoverished
compared to the color perception of birds, reptiles, and fish.

--
Cut "to the chase" for my email address.

rw wrote:

Awhile ago the question of color of flies came up in ROFF. Some people
(including me) thought that fish would likely see colors very
differently from people. Others (rdean, for example) thought that there
would be a one-to-one relationship between the colors fish see and the
colors fish (we?) see, so it wouldn't matter.


Most mammals have only two types of cones

what about Cone Heads?

..........basically I agree. Color is an interesting subject.
Perhaps they see it differently, but if rdean is right,
it doesn't matter. Either way
there is no way to know, except by hunch and by
trial and error. Raptors can see ultra violet reflected by gopher
urine.
So our perception of gopher **** is not one to one with
raptors.

I just thought it was interesting. Pmds do indeed look
very yellow from a distance. And they look gray-olive
up close. Does it matter to the fly tyer?

**** I dunno.

pittendrigh wrote:

.........basically I agree. Color is an interesting subject.
Perhaps they see it differently, but if rdean is right,

That would be a first.

--
Cut "to the chase" for my email address.

rw wrote in news:44c55670$0$24181
:


Primates (including humans) apparently re-evolved a third type of cone
(toward the blue end of the spectrum), probably because they had to
distinguish between different types of ripe fruit.



Some primates have interesting dimorphisms. In the squirrel monkey, for
example, all of one sex are trichromats, and something like 70% of the
other sex are bichromats.

--
Scott
Reverse name to reply

pittendrigh wrote:
.........basically I agree.

rw wrote:
That would be a first.


I think I agree with most (certainly not all) of what
you say, at least for on-topic stuff.
But it occured to me I am more likely to respond
when I do disagree.

Maybe everybody does that. Maybe that's why usenet
tends to be so contentious.

On 7/24/06 7:30 PM, in article
, "rw"
wrote:

pittendrigh wrote:
...got a few new photos, from Saturday, of the tail end
of the Pmd hatch on the spring creeks near Livingston, MT.
One of the things I noticed was how remarkably yellow these
little mayflies look at a distance, and how much greener
and grayer they look close up.

http://montana-riverboats.com/Pages/...iers/Sandy_Pit
tendrigh/Mayflies/PaleMorningDuns/RealBugs/RealBugs.html

Awhile ago the question of color of flies came up in ROFF. Some people
(including me) thought that fish would likely see colors very
differently from people. Others (rdean, for example) thought that there
would be a one-to-one relationship between the colors fish see and the
colors fish see, so it wouldn't matter.

There was an interesting article in Scientific American a couple of
months ago that's relevant.

Humans have three types of "cones," the color-sensitive receptors in the
retina. More "primitive" vertebrate species (reptiles, birds, and
presumably fish) have four types of cones, with their sensitivity
extending well into the UV (ultraviolet) part of the spectrum.

Most mammals have only two types of cones. Mammals hypothetically lost
part of their variety of cone receptors during a long period of
evolution when they were primarily nocturnal, when color perception was
unimportant, and when sensitivity to brightness was of paramount importance.

Primates (including humans) apparently re-evolved a third type of cone
(toward the blue end of the spectrum), probably because they had to
distinguish between different types of ripe fruit.

Nevertheless, human color perception is presumptively impoverished
compared to the color perception of birds, reptiles, and fish.

Dr. Seidman, paging Dr. Seidman. Dr. Seidman to the ROFF(T) operating
theater please.

:-)

Bill

pittendrigh wrote:
pittendrigh wrote:

.........basically I agree.


rw wrote:
That would be a first.



I think I agree with most (certainly not all) of what
you say, at least for on-topic stuff.
But it occured to me I am more likely to respond
when I do disagree.

Maybe everybody does that. Maybe that's why usenet
tends to be so contentious.

You evidently misunderstood me -- probably my fault. The text I quoted
was: " .........basically I agree. Color is an interesting subject.
Perhaps they see it differently, but if rdean is right,"

Rdean being right is what would be a first.

--
Cut "to the chase" for my email address.

"pittendrigh" wrote in message
ups.com...

rw wrote:

Awhile ago the question of color of flies came up in ROFF. Some people
(including me) thought that fish would likely see colors very
differently from people. Others (rdean, for example) thought that there
would be a one-to-one relationship between the colors fish see and the
colors fish (we?) see, so it wouldn't matter.


Most mammals have only two types of cones

what about Cone Heads?

.........basically I agree. Color is an interesting subject.
Perhaps they see it differently, but if rdean is right,
it doesn't matter.

It will come as no surprise to those who have studied the matter of color
perception in depth (nor to those familiar with the corpus of his work) that
dicklet IS right. The confusion over color vision goes way back to
prehistoric times when the cave painters at Lascaux (and sundry other
archeological sites) first perpetrated the hoax that color exists (in some
objective sense) in the real world. No one has yet determined how they
managed this trick with the limited technology of the time and given the
presumably primitive state of scientific knowledge available to them, but
the subsequent photographic evidence is indisputable. Prior to the seminal
work of Niepce, Daguerre, Talbot and other photographic pioneers in the
early nineteenth century, the fraud was universally accepted.....largely as
a result of the huge volume of deceitful work done by painters, glazers,
dyers, etc. Even such supposedly objective and honest luminaries as the
proto-scientists of The Enlightenment were in on the gag.....see Sir Isaac
Newton's "Opticks" for an illuminating example. It was only in light of the
startling discoveries concerning the chemical characteristics of various
silver salts (as well as numerous other light sensitive chemicals.....see:
http://www.edinphoto.org.uk/1_P/1_ph...es_table_1.htm
for an extensive inventory) that it became possible to demonstrate that the
world is actually monochromatic. Unfortunately, the debate continues to
rage to this day because, in the first place, no one could prove beyond
dispute whether the world is sepia, violet, grayscale, or any of several
other (and mostly lesser) contenders and, in the second, because of the
iniquitous influence of such charlatans and mountebanks as George Eastman
and his ilk. Then too, the insidious and ubiquitous advent of so-called
"Technicolor" inundated the masses with a never ending stream of transparent
propaganda which was later (and continues to be) augmented by the pernicious
influence of Ted Turner and the evil geniuses at Adobe. Somewhat ironically
(and fortunately....for those of us with a keen interest in epistomology and
ontology, anyway), the strategy of the latter has backfired on them as they
inadvertantly wrote into their software a capacity to return doctored images
to their true black and white.......um.......color.

Either way
there is no way to know, except by hunch and by
trial and error.

Well, there's also science......and thinking......and stuff.

Raptors can see ultra violet reflected by gopher
urine.

I have it from an unimpeachable authority that there's no way to know that
except by hunch and trail and error.

So our perception of gopher **** is not one to one with
raptors.


Well, maybe not to you, but I certainly can't tell them apart.

I just thought it was interesting.

Nope......not in the least.

Pmds do indeed look
very yellow from a distance. And they look gray-olive
up close.

A number 10 welding filter will fix that.

Does it matter to the fly tyer?

****, I dunno.

**** I dunno.

And yet, basically, you agree.

Wolfgang
no animals, words, images.....or anything else for that matter..... were
photoshopped in the production of this message.

Scott Seidman wrote:
rw wrote in news:44c55670$0$24181
:


Primates (including humans) apparently re-evolved a third type of cone
(toward the blue end of the spectrum), probably because they had to
distinguish between different types of ripe fruit.




Some primates have interesting dimorphisms. In the squirrel monkey, for
example, all of one sex are trichromats, and something like 70% of the
other sex are bichromats.

Interesting.

Red-green color blindness is far more common in men than in women.
That's because the genes for the red and green cones are located on the
X chromosome, of which women have two and men have one. A woman can have
one defective X chromosome and still have normal color vision, because
the other chromosome will make up for it.

--
Cut "to the chase" for my email address.