The Nature of Color | µChicago

Research from the MBL laboratories of Nipam Patel and Carrie Albertin is featured in the July issue of µChicago, the university's monthly science e-newsletter. Sign up here to subscribe.

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 vibrant greens and blues—are a trick of light.

Blue jays aren’t blue; they’re brown. Blue morpho butterflies aren’t blue either. These brilliant blues are examples of structural color, created by the microscopic shape of a material that bends and scatters light in a way that amplifies certain visible wavelengths. Imagine a soap bubble: 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. 

Source: The University of Chicago