Ultraviolet pigment gives butterflies ability to identify own species

Washington, Feb 17 (ANI): In a new research, scientists have found that butterflies that have a duplicate gene allowing them to see ultraviolet colors also have UV-yellow pigment on their wings, which enables them to identify their own species.

The finding, by biologists at the University of California, Irvine (UCI), holds true in at least nine Heliconius species.

The UV-yellow pigment may help the butterflies survive by facilitating the search for appropriate mates, which leaves more time for reproducing, eating and thriving.

"They're not wasting their time chasing after the wrong mate," said Adriana Briscoe, associate professor of ecology and evolutionary biology at UCI and lead author of the study.

The scientists believe that butterflies developed a copy of their UV-vision gene and began displaying UV-yellow pigment 12 million to 25 million years ago.

Of the 14,000 butterfly species in the world, only the Heliconius living in the forests of Mexico and Central and South America are known to have the duplicate gene.

After researchers discovered the copied gene, "we wanted to find out why it might be advantageous," Briscoe said.

They examined thousands of wing-color patches and found that butterflies with just one UV-vision gene had yellow wing pigment that was not UV.

However, the pigment was UV in butterflies with both genes.

Early naturalists hypothesized that wing-color mimicry - causing butterflies to resemble bad-tasting relatives - emerged as a defense mechanism to confuse predators such as birds.

This created a problem, though. Butterflies that evolved to look alike had a hard time identifying the right species with which to mate.

Having both genes allows molecules to form in the eyes that are more sensitive to UV light.

"We think that by switching to a new way of making yellow, the mimetic butterfly species were better able to tell each other apart," Briscoe said.

"We now have strong reason to believe that we'll find other examples in which vision and wing colors are linked," said Briscoe. (ANI)