The dull gray and brown coats of moths may not capture our imaginations as much as their colorful moth cousins, but according to a recent study, it’s more of a lapse in human eyesight than moths. night themselves.
By photographing the wing scales of 82 moths from 26 different species using a camera that captures an extra-wide spectrum of light, the researchers observed the insects in infrared: wavelengths from light too long for humans to see. In infrared, the buff and tan wings we’re used to seeing fluttering around outdoor lights take on vibrant, iridescent colors, the researchers reported. in the Royal Society Interface Journal.
Beyond exposing the beauty of moths, the new data also revealed species-specific structural differences in how insect wings reflect and scatter infrared light. The diversity of these infrared characteristics, which come from microscopic scales that cover the wings of moths— could possibly help scientists identify species of moths using lidar (light detection and ranging), a tool that emits and detects infrared light.
Scientists are already using radar to count moths in the field. But the species details could help scientists track the creatures’ variable nocturnal migrations, which serve as primary food sources for birds and other animals.
Radar entomologist Alistair Drake of the University of New South Wales in Australia notes the potential limitations of lidar for monitoring moths. “The problem with lidar is that it has a very narrow beam,” says Drake, who was not involved in this study. Radar beams used to detect insects can be 60 to 100 feet wide, large enough to capture many individual organisms passing by, while lidar beams only extend a few centimeters, or about the size of a single moth. “So we don’t really know if the vertically pointing lidar beam will produce enough insect crossings to be useful.”
To test the proposed moth-spotting method, the study’s lead author, Meng Li, an optics expert who researches remote insect detection tools at Lund University in Sweden, and her team are evaluating in how well the lidar captures the different moths around their study site. “We’ve been monitoring since April with radar, lidar and trap,” she says. “So if there is a large migration of some butterflies, it will appear in all three.”