Peppered moths do not normally rest on tree trunks. In decades of field
work, only one peppered moth was found resting on a tree trunk in the
wild. Kettlewell released his moths near the ground in the morning, which
would have caused the moths to land on the trunks unnaturally. Pictures
showing moths on trunks were staged. This invalidates the research that
was based on the assumption that they normally rested on trunks.
Peppered moths do not rest exclusively on tree trunks, but they do rest
there. Of the forty-seven moths one researcher found in the wild,
twelve were on trunks and twenty were on trunk/branch joints. (The
other fifteen were on branches). The numbers and proportion on trunks
near light traps were even higher (Majerus 1998, 123). Wells's claim
that the moths do not naturally land on trunks is simply a falsehood.
Branches provide a background similar to trunks.
Photos showing moths on trunks were staged but only for purposes of
illustration. The photographs depict what is found in the wild,
whether trunk or branch. Furthermore, the photos played no part in the
scientific research or its conclusions.
References:
Majerus, Michael E. N., 1998. Melanism: Evolution in action, Oxford
University Press.