The Nature of Color | µ󾱳

The Buckeye butterfly (Junonia coenia) with a partial Ubx gene knockout. Credit: Aaron Pomerantz

Research from the ǧƵ laboratories of Nipam Patel and Carrie Albertin is featured in the July issue of µ󾱳, the university's monthly science e-newsletter. 

Nature is painted with pigments—molecules that produce color by absorbing certain wavelengths and reflecting others. Chlorophyll is the pigment that makes plants green; melanin is a pigment that gives humans our eye, hair, and skin color. But some colors found in nature—especially  and blues—are a trick of light.

Photo: Wild-type buckeye butterfly (Junonia coenia, left) compared to a mutant with the optix gene deleted (right). Credit: Rachel Thayer, Patel lab
Wild-type buckeye butterfly (Junonia coenia, left) compared to a mutant with the optix gene deleted (right). Credit: Rachel Thayer, Patel lab

Blue jays aren’t blue; they’re brown.  These brilliant blues are examples of  color, created by the microscopic shape of a material that bends and scatters light in a way that amplifies certain visible wavelengths. Imagine a : the film is clear, but you see swirls of color when it floats in sunlight. These nanostructures are what make peacock feathers, beetle carapaces, and butterfly wings so vivid.

Buckeye butterflies are usually brown with small (structural) blue flecks. (So far, only the olivewing butterfly is known to have blue pigment.) Over the course of a year, a butterfly breeder mated buckeyes that had the most blue, and this artificial selection forced a “rapid evolution” and created blue-winged buckeyes. Marine Biological Laboratory scientists took the opportunity to study the evolutionary mechanisms that change the tiny overlapping scales that give butterfly wings their color. 

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