What makes their colors pop — almost glow — is the contrast with the tiny spider’s super-black velvet patches, according to a recent paper in the Proceedings of the Royal Society B by Dakota McCoy, a Ph.D. student in the Graduate School of Arts and Sciences and a researcher in the lab of George Putnam Professor of Biology David A. Haig. McCoy’s research is the first to suggest that the highly absorbent, anti-reflective black surface is characterized by an array of bumps known as “microlenses,” reminiscent of those found in man-made anti-reflective materials.
“The microlens arrays on the spiders, which have evolved in a peculiar shape optimized for anti-reflection, are very similar to man-made surfaces. Perhaps their particular size and shape could help us design better solar-capture devices,” she said.
The research follows on McCoy’s 2018 discovery that the same muted deep black — which reflects only half a percentage point of light — makes nearby colors on the feathers of the male birds of paradise seem ultra-bright.
McCoy hopes understanding the light-absorbing abilities of these flashy spiders will lead to new applications. Engineered microlenses could eventually, for example, help prevent glare on eyeglasses or enhance the absorbency and efficiency of solar energy cells. McCoy, who is now looking to team up with an engineer to create a prototype, envisions a polymer microlens film that could be laid over lenses or solar cells.
The deep black on male peacock spiders eliminates nearly all white highlights, spots of light that appear on shiny surfaces and serve as visual reference points to help us calibrate color perception, making bordering colors appear luminous.
