November 16, 2011
Ancient Moths Reveal Wing Colors
New research is allowing scientists to learn what the colors of fossilized moths would have been. Maria McNamara, a paleobiologist and postdoctoral researcher at Yale University was examining fossils from oil shale in Germany when she came across the remains of several moth species, all belonging to a group called lepidopterans, which also includes butterflies.
“Until now, we had no idea what colors ancient moths and butterflies had,” McNamara relates to Stephanie Pappas of MSNBC.
Moths and butterfly wings have what´s known as structural color, rather than pigments. Structural colors are created by nanoscale surface features and can be preserved if fossilization occurs delicately and the intervening conditions leave the fossils relatively undisturbed.
McNamara began her research by studying the colors of ancient beetle fossils, which are common. “There are loads of beetle fossils with some evidence of color, but this had never been found for a lepidopteran at all,” she said.
The research team used an electron microscope to photograph the wing surface of the fossil and based on what´s known from similar structures in living moths and butterflies, the 47-million year old fossil should appear yellow-green rather than slightly yellow-blue, a difference likely caused by subtle structural changes during fossilization, Wired Magazine´s Brandon Keim reports.
Reconstructing the color of the moths may provide paleontologists with clues about the habits of the prehistoric moth, writes Brian Switek for Science Now. The green hue combined with a lack of iridescence on the moth´s wings, McNamara suggests, are features often associated with camouflage among modern insects.
The coloration would have aided the moth in hiding from would-be predators such as bats, in the ancient Messel forest. Additionally acting as a deterrent, “The color would have been very conspicuous when [the moths] were feeding on flowers,” McNamara says, “when it probably would have served as a warning signal” to let predators know that they are toxic and taste awful.
What those colors meant for the insect´s lifestyle is more difficult to discern, Daniel Janzen of the University of Pennsylvania cautions. The bright hues could have been useful for courtship, camouflage, or communication, as seen among living moths.
Janzen notes that the connection between colors and behavior can be applied to the fossil record just as it can to modern moths: “We have no reason to suspect that basic field ecology was different 40-plus million years ago than it is today.”
The study was published in the Nov. 15 issue of PLoS Biology.
Image 2: A research team led by Yale University scientists has reconstructed the colors of a 47 million-year-old day-flying moth based on anatomical details in fossilized scales. Scientists know the actual colors of few ancient creatures. The discovery could help them learn the colors of a wide variety of long-extinct creatures, including birds, fishes and other insects, shedding light on color´s function and evolution.
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