Animals

New Form of Color Discovered on Peacock Spider

The spider has white, cream and red pigments, but its dazzling blue is where the new type of color was found.

<em>Jürgen Otto</em><br>

Male peacock spiders display a form of "structural" color that's never been documented before, according a new paper published in the Journal of the Royal Society Interface.

Structural color itself is well known and has been documented in many species, from peacocks to beetles. It's much less common than pigment coloration, where natural substances give color to plants and animals.

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Lead author Doekele Stavenga, a professor of computational physics at the University of Groningen, told Discovery News, "The red and yellow colors are due to pigmented scales. We found that the blue color is caused by special, structural-colored scales."

Photo: Closeup of the male peacock spider's head and eyes. Credit: Jürgen Otto

Stavenga and colleagues Jürgen Otto and Bodo Wilts used scanning electron microscopy and other techniques to study the spider's colors in depth. They discovered that the blue is not only a structural color, but that it's a type that's never been described before.

"The special photonic invention of the Maratus splendens scales is the insertion of two layers of extremely fine threads or filaments that subtly tune the refractive index profile of the multilayers, thus creating the distinct, blue color," Stavenga explained.

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The male peacock spiders use the patterns and colors on their bodies for visual communication, including wooing attentive females.

You can see them in action in this video, shot by Otto:

The mating display does look like dancing, as editor Dario Trovato noticed: