Re: Pepperred moths

Kevin O'Brien (
Thu, 1 Apr 1999 17:05:45 -0700

>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.

In fact Majerus establishes through his own research and that of others that
the natural resting site is on branches; perhaps you should read his book.

>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.

Night predators do not hunt by sight, but by sound or feel or smell. As
such, night predation would not be selective for body color. Since the
research reported by Majerus in his book establishes that the predation was
selective for body color, and that it was this selective predation that
accounts for the shift in body color, that would rule out night predators as
having any significant selective affect. Again, perhaps you should read
Majerus's book.

>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.

This is flatly contradicted by the evidence provided by Majerus; again,
perhaps you should read his book.

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

In point of fact we do, but even if this were not the case, we know that the
shift in morphology must be due to a shift in genes, or do you dispute that

>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.

Again, this is contradicted by the evidence given by Majerus; again, perhaps
you should read his book.

>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.

As Majerus himself explains, these photos were meant to educate
non-scientists on the contrast between body color and background color, not
to serve as scientific data on the behavior of the moth itself. Again,
maybe you should read Majerus's book.

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

A better question is, how can you imply to be a better judge of this subject
than Majerus when in fact you are ignorant of much of the key data?

Again, why don't you read Majerus's book and find out what the real
information is, rather than rely on your own ignorance?

Kevin L. O'Brien