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