Butterfly Changes from Drab Brown to Brilliant Blue After Scientists Influence Its Evolution

Butterflies are known for their colorful wings, cast in shades that range from indigo to crimson. Now, scientists are using these brilliant hues to their advantage. They've managed to change the color of butterfly wings by influencing the insect's 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 Antonia Monteiro, one of the researchers, in a news release.

In this case, the researchers chose the butterfly Bicyclus anynana, an insect which normally has brown wings. They chose this particular species because it has cousin species that have evolved violet colors in their wings twice independently. Intrigued by this, the researchers wanted to see if they could cause the butterfly to swap drab browns for brilliant blues.

"We just thought if natural selection has been able to modify wing colors in members of this genus of butterfly, perhaps so can we," said Monteiro.

In this case, the researchers used six generations of butterflies in an attempt to change the color of the wings. In the end, they succeeded. The insect swapped out brown for violet. This, in particular, was achieved by changing the relative thickness of the wing scales-specifically, those of the lower lamina. In all, it took less than a year.

"Today, materials engineers are making complex materials to perform multiple functions," said Hui Cao, one of the researchers involved with the study. "The parameter space for the design of such materials is huge, so it is not easy to search for the optimal design. This is why we can learn from nature, which has obtained the optimal solutions in many cases via natural evolution over millions of years."

The findings reveal that natural selection algorithms can select for multiple characteristics simultaneously. More specifically, this work reveals how researchers can select a particular outcome and then use evolutionary principles in order to achieve that outcome.

The findings are published in the Proceedings of the National Academy of Sciences.