(David Hershey) wrote in
om:

Sean Houtman wrote:

There isn't any real evolutionary
pressure for a tree to be pretty in the fall, it is just
something that some of them do.


There are two major hypotheses to explain colorful fall leaves.
One is that red anthocyanins act as a sunscreen and act as
antioxidants. The other is that colorful leaves repel insects.


The Warm Hues of Fall Foliage Competing theories try to explain
the season's spectacular show of color, but most come up short:
http://www.sciam.com/article.cfm?art...F26-7ABD-1D94-
92758
09EC5880105

A Puzzle for the Autumnal Equinox:
http://www.corante.com/loom/archives/015786.html

Why Leaves Turn Color in the Fall:
http://www.the-scientist.com/yr2001/...p8_011210.html




Yes, I have no arguement with the usefulness of the pigments in the
leaves. If there was no advantage given, the plants would not expend
so much energy making the pigments. It is just that the pigments are
not there to make the leaves pretty in the fall, and the effect of
nice colors just before the leaves drop does not improve the chances
that the tree will reproduce.

Sean