Butterflies Switch Up Wing Colors when Adapting to Changes

A butterfly's wings help carry the creature in search of nectar to nearby flowers. Yet did you know that some of these insects' wings change color?

Recent findings published in the journal Proceedings of the National Academy of Sciences found that these creatures actually used structural color changes to influence their evolution.

"What we did was to imagine a new target color for the wings of a butterfly, without any knowledge of whether this color was achievable, and selected for it gradually using populations of live butterflies," said Antónia Monteiro, a former professor of ecology and evolutionary biology at Yale, now at the National University of Singapore, in a news release.

For the study, Monteiro and her team changed the wing color of the butterfly Bicylus anynana from brown to violet using only six generations of selection.

Though little is known about how structural colors in nature evolved, the researchers tried to copy what they found in their laboratory. 

"Today, materials engineers are making complex materials to perform multiple functions. The parameter space for the design of such materials is huge, so it is not easy to search for the optimal design," added Hui Cao, chair of Yale's Department of Applied Physics, who also worked on the study. "This is why we can learn from nature, which has obtained the optimal solutions in many cases via natural evolution over millions of years."

Researchers found that a certain color of the butterfly wing was achieved by changing the relative thickness of the wing scales-specifically for those of the lower lamina. Furthermore, it took less than a year of selective breeding to produce the color change.

A reason why researchers chose Bicyclus anynana over other butterflies, according to researchers, is that it has cousin species that evolved violet colors on their wings twice independently. While recreating this effect in the lab, researchers found that butterfly populations harbor high levels of genetic variation regulating scale thickness that works to react quickly to new conditions.