In a first, butterfly wing colours changed in lab

In groundbreaking work, scientists have changed the colour of butterfly wings - the first such structural change in an animal by influencing evolution.

"What we did was to imagine a new target colour for the wings of a butterfly, without any knowledge of whether this colour was achievable, and selected for it gradually using populations of live butterflies," said Antonia Monteiro from National University of Singapore.

The discovery may have implications for physicists and engineers trying to use evolutionary principles in the design of new materials and devices.

The researchers changed the wing colour of the butterfly Bicyclus anynana from brown to violet for which they needed only six generations of selection.

The desired colour for the butterfly wings was achieved by changing the relative thickness of the wing scales - specifically, those of the lower lamina.

It took less than a year of selective breeding to produce the colour change from brown to violet.

One reason Bicyclus anynana was chosen for the experiment, Monteiro said, was because it has cousin species that have evolved violet colours on their wings twice independently.

Little is known about how structural colours in nature evolved, although researchers have studied such mechanisms extensively in recent years.

Most attempts at biomimicry involve finding a desirable outcome in nature and simply trying to copy it in the laboratory.

The study appears this week in the journal Proceedings of the National Academy of Sciences.