<i><a href="//commons.wikimedia.org/wiki/Biston_betularia" title="Biston betularia">Biston betularia</a></i> caterpillars on <a href="https://en.wikipedia.org/wiki/birch" class="extiw" title="w:birch">birch</a> (left) and <a href="https://en.wikipedia.org/wiki/willow" class="extiw" title="w:willow">willow</a> (right).
Noor MAF, Parnell RS, Grant BS
CC BY 2.5
A Reversible Color Polyphenism in American Peppered Moth (Biston betularia cognataria) Caterpillars. PLoS ONE 3(9): e3142. <a href="//doi.org/10.1371/journal.pone.0003142" class="extiw" title="doi:10.1371/journal.pone.0003142">doi:10.1371/journal.pone.0003142</a>