Pepperred moths

Arthur V. Chadwick (
Thu, 01 Apr 1999 06:37:58 -0800

Let's see if we can improve the signal-to-noise ratio a little by
crystallizing what it is we are discussing.
I think we would all agree with the following:

1. We do not know where the peppered moths spend their daylight hours, but
we know it is not on the trunks of trees.

2. We do not know what the primary predator of peppered moths is, but since
they fly at night it is most likely something other than birds.

3. We do not know why the moths shifted to darker morphotypes
(simultaneously in U.S. unpolluted areas and Britain polluted areas), but
we know that they did.

4. We do not know what genetics or lack thereof are behind the shift in

5. We do not know why the moths shifted back to the lighter morphotypes,
but we know it is not due to any mechanism we yet understand.

6. We know that the pictures in textbooks were made under circumstances
other than those that would be considered natural, and that their relevance
to the behavior of the peppered moths is thus questionable at best.

Given the above, what can we say about evolution that we have learned from
the peppered moth?