Moth Wings Are Beautiful in Infrared Light

Moth Wings Are Beautiful in Infrared Light

Drab brown moths’ infrared glittering could be key to tracking different species through the night

Each moth’s left half is shown in true color, and the right shows an enhanced view based on infrared wavelengths. Credit: From “Potential for Identification of Wild Night-Flying Moths by Remote Infrared Microscopy,” by Meng Li et al., in Journal of the Royal Society Interface, Vol. 19, No. 191; June 22, 2022

Moths’ dull gray and brown colors may not grab our imaginations as much like their colorful butterfly cousins, but a recent study shows that this is more a result of humans’ poor eyesight than moths themselves.

By photographing the wing scales of 82 moths from 26 different species using a camera that captures an extra wide spectrum of light, researchers viewed the insects in the infrared: wavelengths of light too long for humans to see. In infrared, the buff and beige wings we are used to seeing flutter around outdoor lights take on vibrant, iridescent colors, the researchers reported in the Journal of the Royal Society Interface.

The new data revealed species-specific structural differences in the way that moth wings scatter and reflect infrared light. The diversity of these infrared features–which come from microscopic scales that cover moth wings–could eventually help scientists identify moth species using lidar (light detection and ranging), a tool that emits and senses infrared light.

Scientists use radar to identify moths in the field. Scientists could use species details to track the moths’ nocturnal migration patterns, which are important food sources for birds and other wildlife.

Radar Alistair Drake, an Australian entomologist, notes the potential limitations of lidar in moth monitoring. Drake, who was not part of this study, said that lidar has a narrow beam. The radar beams used to detect insects can be 60 to 100 feet across, big enough to capture lots of individual organisms flying past, whereas lidar beams span only a few inches–about the size of a single hawk moth. “So, we don’t know if the vertical-pointing lidar beam will produce enough insect crossings .

To test the proposed moth-spotting technique, Meng Li (study lead author and optics expert at Lund University in Sweden) and her team are evaluating the effectiveness of lidar in capturing the various moths that live around their study site. She says, “We have been monitoring since April using radar, lidar and traps.” “So if there’s a large migration of certain moths it will appear in all three .”

This article was originally published with the title “From Drab to Fab” in Scientific American 327, 4, 16-17 (October 2022)

doi: 10. 1038/scientificamerican1022-16a


    Daniel Lingenhohl is editor in chief of the magazines Spektrum der Wissenschaft and Gehirn&Geist. Follow him on Twitter @lingenhoehl

      Sasha Warren was a 2022 AAAS Mass Media Fellow at Scientific American. They are currently working o

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