Apparently, pete is right to suggest that some moths were glued to trees. This was, apparently, done to determine the effect the density of moths had on predation.

See: Lots of moth discussion : which took me by surprise.

And, also apparently, the original photographs of moths on bark were staged.

BUT, the final development of Kettlewell's work on the moths (See Discussion of Kettlewell's work. ) used the capture, mark, recapture technique to estinmate populations, and did not depend on any observations, photographed or not, of glued moths.

FURTHERMORE, the observation that with the drop in heavy industries, the light form of the moths showed a resurgence is independent of that work, and serves to confirm the effect of differential predation.

The OU foundation science course included a module on this experiment - I didn't catch any peppered moths with the lamp they issued, so cannot comment directly (I lived in the wrong place). But if the many students involved had shown up any problems, I would think it would have been published by now. There's plenty of discussion about the mothy business by non-creationists out there.

Penny