A new study shows that scientific research on moth camouflage does not require evolutionary theory.
Evolutionary biologists from Seoul, South Korea filmed moths resting on tree trunks. According to PhysOrg, they were trying to understand how moths in the wild orient themselves on the bark for greatest camouflage. That’s a very different question than the ones asked by Kettlewell, Majerus and other past researchers who were looking for natural selection of peppered moths. In those old studies, camouflage was a happenstance, not a behavior within the moth. The opening paragraph referred to the old ideas as if preparing to dismiss them:
Moths are iconic examples of camouflage. Their wing coloration and patterns are shaped by natural selection to match the patterns of natural substrates, such as a tree bark or leaves, on which the moths rest. But, according to recent findings, the match in the appearance was not all in their invisibility… Despite a long history of research on these iconic insects, whether moths behave in a way to increase their invisibility has not been determined.
In other words, Kettlewell and Majerus didn’t take into account the moths’ behavior. They treated moths as passive creatures that would alight on tree trunks at random. They placed the selective power in the environment, with lower contrast producing greater camouflage, leaving the high-contrast moths vulnerable to birds.
The South Korean researchers found, instead, that moth behavior plays a vital role in the camouflage. They “found out that moths are walking on the tree bark until they settle down for resting; the insects seem to actively search for a place and a body position that makes them practically invisible.” A video clip embedded in the article shows the moths doing this….
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