Until now, the wing colors of many flies and wasps were dismissed as random iridescence. But they may be as distinctive and marvelous as the much-studied, much-celebrated wings of butterflies and beetles.
“Given favorable light conditions, they display a world of brightly patterned wings that are apparently unnoticed by contemporary biologists,” wrote researchers led by University of Lund entomologists Ekaterina Shevtsova and Christer Hansson in a December 3 Proceedings of the National Academy of Sciences paper.
Wasp and fly wings are made from two compressed layers of transparent chitin, with light bouncing off both layers and mixing to produce color. The same is true of oil slicks and soap bubbles, and scientists considered transparent wing coloration “a soap bubble iridescence effect, with randomly changing colors flashing over the wing surface,” wrote the researchers.
Instead, the researchers found that surface variations in chitin filtered out the iridescence. Remaining colors proved to be stable, and were visible from almost any angle. They differed consistently between species and sex.
Generations of biologists seem to have missed this partly because they didn’t look for it, and partly because the colors are most evident against a dark background. Against a white background, they’re invisible — which is exactly how most entomologists study transparent wings.
read here more