Chris Slade wrote:

>Colour  variation usually does not show a significant
>correlation with either of  the two referential dimensions
>[neither latitude nor  time]
>How about altitude?

Color. I had an article about honey bee coloration in the American Bee
Journal last June. Color in bees does not seem to correlate to
anything. There are black, yellow, and striped bees in the tropics.

If you study evolution you will see that the main thing is change.
Variation is the engine of change. Some changes are beneficial and are
retained and enhanced over time. Some changes are harmful and those
traits or lineages drop out over time. However, some changes have
*neutral* value. The variation in the shapes of tree leaves is an
example of this.

In the article they state:
> The characters of wing venation, on the other hand, can be interpreted by neutral (nonadaptive) evolution, in which the magnitude of divergence is proportional to time of divergence.

Wing veins in bee species are very similar but can be used to identify
different species and even the so-called races. This is due to what is
called genetic drift. Over time the pattern just changes and can be
used to calculate how long ago the type were separated.

Color may be another neutral trait. I simply can't see ho wit would
have much adaptive value. The size of bees, on the other hand, seems
to correlate to winter temperature. One can easily see how a slightly
bigger bee might evolve due to better heat retention in winter.

-- 
Peter L. Borst

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