Trevor Weatherhead said:

> Looking back in the archives, I have been looking for examples
> where beekeepers have been using colours on their hives to help
> with queen returns.  There are many useful hits in the archives
> but is there anyone who is now using colours for this purposes.

> Can they list what colours they are using.

I only use them on new splits, I do not use them on every hive.
Perhaps if I convert to pallets someday, I will use them everywhere.

I don't think that it matters what specific colors one uses.
What matters is to choose different colors that are "far apart
from each other" in the color spectrum to maximize the ability
to differentiate between multiple entrance choices in the same
(lets guess and say "15-degree" as an estimate) "field of view".

The color ranges that bees are known to see run from orange up
to the ultraviolet wavelengths.  Bees see red as "black", so one
could use either red or black as "black" for bees.

The exact color range of bee vision ranges from somewhere between
300 and 400 nanometers wavelength to somewhere slightly above 600
nanometers.  (The published literature gives different numbers,
and I don't know which is exactly correct.) In terms of colors,
this means:

Wavelength      Aprox Color     Bee     Human
(nm)            Range           Sees?   Sees?
-----------     -----------     -----   -----
300             Ultraviolet     Yes     No
400             Purples Yes     Yes
                Blues           Yes     Yes
                Blue-green      Yes     Yes
500             Green           Yes     Yes
                Yellow  Yes     Yes
600             Orange  Yes     Yes
700             Red             No      Yes
800             Infrared        No      No

So, orange and blue are "further apart" than green and yellow.
I would not expect as much success from a green/yellow choice
as I would from a orange/blue choice.

I have seen various marker set-ups, but I think that most
(including all the university research set-ups I have seen)
attempts at this are not thought out very clearly in terms of
making unique "markers" for bees.

All of what I have seen have used consistent shapes.  For example,
at EAS 2002, those who attended the "apiary workshops" could see
that Cornell uses sets of 4 square tiles, with each square tile
painted a different color.  The 4 tiles are themselves arranged
into a larger square.

What's wrong with this approach?  Get a magnifying glass, and look
closely at your TV or computer screen.  You see "pixels".  You see
individual red, green, and blue dots.  If you look at the screen
without the magnifying glass, you see the net effect, which looks
like colors "between" the reds, blues, and greens.  The pixels are
smaller than your eye can resolve, so your eyes get fooled and see
"purple" rather than "red next to blue".

So what do these Cornell square "targets" look like to a bee on
final approach, heading for a cluster of 4 to 6 hives?  Well, what
do they look like to you at 50, 100, 150, and 200 feet?  Given that
each square is no more than a 2 or 3 inches across, I'd conclude that
they are useless (and perhaps confusing) at somewhere between 50
and 100 feet.  At a flight speed of 6 to 9 miles an hour, the typical
bee is moving at 8 to 13 feet per second.  So if they can only
resolve the "target" at 50 feet, this gives them only 3 to 6 seconds
to see the target, make a decision, and change course.  All while
making a landing amongst hundreds of other flying bees.

We know that the resolution of bee vision is lousy as compared to
humans, so a bee attending Cornell has to get close to a hive to
be able to resolve the different color patches as individual colors.
How close to they have to get before they can resolve the individual
colors? I dunno, but bees have far fewer "sensors" in their eyes
than humans, and a bee's eye covers a much larger area of the sky
than a human eye.  If you can't make out the difference, a bee surely
can't.

I'd suggest that different shapes AND colors would make recognition
easier for the bees.

Good examples of what I would use are triangles, stars, and various
"gunsight cross-hair" patterns, in colors that contrast well with
the hive bodies or the "background" portion of the marker.

My reasoning for suggesting that patterns are as important as
color is as follows:

Bees can see all the same colors that humans can, except reds.
They see "red" as "black", assuming that neither object fluoresces
under UV light.

The light sensors in the eyes of insects are called "ommatidia" by
entomologists.  A honeybee eye has 4500 of them, all pointing outward
at unique angles to collect light from different directions. A mere 4500
photoreceptors makes for a very low resolution "camera".  A human eye
has 1.5 million photoreceptors, and even cheap digital cameras have
2 or 3 million.

Each bee photoreceptor is made up of nine individual elements. Two detect
green, two detect blue, and two detect ultraviolet. The other two are
(somehow) able to detect green when pointing down, and ultraviolet when
pointing up. (Don't ask me how.)

There are lots of photos of flowers that have been taken under UV light
in an attempt to show the "hidden patterns" that point bees to nectar and
pollen.  All of them can be described as "starbursts" of various types
with darker centers.

Bees clearly have the ability to distinguish patterns, since they will fly
directly between flowers in which they are interested. (And please - before
yet another chowder and marching society forms, let me add that anyone who
wants to look can see bees moving directly from flower to flower against
the breeze, so this is not "odor" at work here.  This is vision.)

So, consider painting triangles, squares, circles, and stars, all with
radiating arms like a child's drawing of the sun, on a contrasting
background.  This is sure to reduce drifting, as bees are accustomed to
such "radiating" patterns.

I use plastic lids from 2-lb coffee cans, since they are free,
indestructible, large enough to make a decent visual target at
a hundred feet, hold paint well, and are easy to thumb-tack
to a hive body.


Two other somewhat obscure aspects of bee vision would allow one to
come up with some very sophisticated bee markers.  (I don't know why
anyone would do this, but I often get the impression that "someone,
somewhere" is doing just about anything that can be done to bees,
just to see what happens.)

A bee's UV-detecting ability can detect the direction of the polarization
of UV light. This allows them to know the sun's position even when the sky
is partly overcast.  When even only a tiny portion of sky is visible, bees
can look at the clear portion, and figure out where the sun is.  Light is
scattered by the atmosphere.  Scattering polarizes, and the polarization
is maximum when the scattering is at 90 degrees.  As the angle to the sun
gets closer to being directly toward or directly away from the sun, the
polarization approaches zero.  If you want to see this effect, Ray-Bans
and other decent sunglasses are polarizing filters. Rotate your sunglasses
slowly, and notice that the direction of polarization is indicated by the
position of the lens that dims your view of the sky the most.

Bees also can resolve rapidly-moving objects (like other bees) that humans
cannot. Bees are said to be able to see motion at 100 Hz (cycles per second).
Humans can only see things moving slower than 20 Hz.  That's why they never
have mid-air collisions in front of the hive.  This ability to see a rapidly
moving object apparently is not very good at a distance, as I have found
dead bees when cleaning the grille screens of my cars.

        jim