Multiple Independent Animal Types Use Structural Color

The phenomenon is found in butterflies, fish, birds, and snakes, and scientists are rushing to imitate their secrets.

At The Conversation, Colin Hall and Eric Charrault describe the gold rush for structural color. These are colors made not with pigments, but with nanometer-scale structures that play tricks with light, intensifying some wavelengths and diminishing others. Coming up with a way to make Vantablack, a structural color that absorbs 99.6% of the light hitting it, was a feat of engineering:

To put this in perspective, if you think of a forest of trees about a metre in diameter, then these trees would scale to be around one kilometre high. Light falling on this very tall forest of tubes bounces around and is almost perfectly absorbed.

The article on cutting-edge attempts to create new colors with structure includes photographs and descriptions of very diverse animals that use this technique:

• Butterflies, that create iridescent colors on their scales. (see 6/15/10)
• A snake that has some of the blackest scales found in nature.
• Sardines with silvery sides.

Live Science shares another secret: “Butterfly Wing Optics Help to Cheaply Create Bright, Realistic Holograms.” The blurry holograms seen at concerts, in movies and on credit cards could much more colorful and clear, David Roos reports, by mimicking the nanostructures on butterfly wing scales.

We know from previous reports on structural colors or “photonic crystals” that birds, spiders, beetles and mammals also use them (6/05/08). These diverse animals could not have gotten their secrets by descent from a common ancestor because many intermediate animals in the evolutionary scheme do not have them. The only other way for evolution to handle this would be for the common ancestor to have the secret, but most animals down the line lost it. That would also create a challenge: how did the common ancestor come up with a trick like that? There’s only one cause that we know of that can share technology across multiple, independent platforms. That cause is – you guessed it – intelligent design.