Image: B.-K. Hsiung et al./Nat. Commun./CC BY 4.0

What Australian peacock spiders lack in size, they make up for in dazzling courtship displays, featuring funky dance moves and an array of bold colors.

Although barely longer than 5 millimeters in length, males are easily able to capture the attention of suitable females with eye-catching mating rituals that involve hopping around and shaking their brightly colored abdomens. But two species, Maratus robinsoni and Maratus chrysomelas, are even more remarkable — they produce fascinating iridescent displays using all the colors of the rainbow.

The key is in the scales that can reflect the full visual spectrum, according to new research published in the journal Nature Communications.

An adult male Maratus robinsoni. The colors on its abdomen look different based on the viewing angle. Image: Dr. Jürgen C. Otto/ Nature Communications

According to a press release, researchers utilized light and electron microscopy, hyperspectral imaging, imaging scatterometry and optical modeling to assemble 3D models that provided insight into how the scales worked.

It turns out the rainbow color is produced by scales shaped like airplane wings that break down visible light down into its integral colors and reflect it off ridges that separate out the hues. This research is not just interesting — it could also be useful in the field of optical technology. The scales could inspire new designs for high-resolution spectrometers and allow scientists and engineers new methods for creating iridescent colors in the modern world.

“As an engineer, what I found fascinating about these spider structural colors is how these long-evolved, complex structures can still outperform human engineering,” stated co-author Radwanul Hasan Siddique. “I wonder how the spiders assemble these fancy structural patterns in the first place.”