Israeli study on how damselflies get their vivid colors could help replace toxic dyes

Scientists at Ben-Gurion University of the Negev in southern Israel have cracked the code of how damselflies produce their striking colors, in a discovery that could help accelerate the replacement of toxic synthetic pigments across industries ranging from cosmetics to textiles.

Damselflies, often colored in metallic turquoise, blue, green, or red, resemble miniature helicopters that whizz over bodies of water during the warmer months.

Their colors are achieved through photonic glasses — tiny spheres packed together randomly to scatter light.

To counter the washed-out effect that can result from slight variations in sphere size, the damselfly has evolved two corrective mechanisms, according to an article published at the end of last month in the Proceedings of the National Academy of Sciences (PNAS).

In the first, the density of the spheres drops as they get larger, ensuring that each sphere reflects the exact same shade of color.

In the second, the spheres are loaded with a yellow pigment. This acts like a filter, absorbing unwanted light while making the main color appear much deeper and more saturated.

“Nature has found an elegant way to produce perfect colors using imperfect parts,” said PhD student Tali Lemcoff, who studied the blue-tailed damselfly (Ischnura elegans).

She added, “These strategies could show us how to build high-quality optical materials using sustainable, organic ingredients instead of the synthetic chemicals we rely on today.”

Lemcoff told The Times of Israel that it was reasonable to assume the findings applied to other damselfly species as well, given that they also have similar light-reflecting structures.

The interdisciplinary team, led by BGU’s Professor Benjamin Palmer and  Lemcoff, included researchers from the Weizmann Institute of Science in central Israel, Lund University in Sweden, Aalto University in Finland and the UK’s Bristol University.