Tarantula tint inspires new ways of making colors

Abstract

Creatures of the night that stalk their prey underground are rarely clad in bright colors. But a surprising number of tarantulas—ground-dwelling, nocturnal predators—carry hairs that are a vivid shade of blue. Last year, researchers found that this hue was surprisingly common; it actually had evolved multiple times in different lineages and converged on remarkably similar shades of blue across 40 of 53 tarantula groups (1). Several types of tarantulas, including this green bottle blue tarantula, have evolved to display a vivid shade of blue that results not from pigments, but from a phenomenon known as structural color. Image courtesy of Shutterstock/Cathy Keifer. Like many shades of blues in the natural world, tarantulas’ tints are not formed by colored pigments. Instead, they’re a result of nanostructure patterns that interfere with specific wavelengths of light, a phenomenon known as structural color. Unlike pigments, which are colored because excited electrons absorb certain wavelengths of light and emit others, structural colors are purely physical arrangements, often created by colorless materials. Figuring out the precise patterns that create tarantulas’ brilliant hues may not only offer up insights into animal adaptations, but could point to means for creating colors from new, less toxic materials: for example, longer lasting, brighter paints. One of the keys to such advances could be a tool most wouldn’t consider for the study of animal hair: 3D printing. The nanostructures in tarantulas take myriad shapes: some are smooth cylinders, …