Fans of prehistoric sketches can now color in their favorite ancient bugs with less guesswork. Modern insects from beetles to butterflies are famous for their metallic hues. These intricate and often iridescent color patterns stem from tiny structural tweaks along the critter's outer exoskeletons, such as alternating layers of ultra-thin tissue that bounce light in different directions. Many fossil beetles are similarly colorful, but scientists weren't sure how the fossilization process may have changed their tints. To get at this color conundrum, researchers examined the nanostructures of old bugs, dating from about 15 million to 50 million years ago, under the microscope. Sure enough, many of the beetles had different colors than their exoskeleton structure seemed to indicate, the group reports online this week in the Proceedings of the Royal Society B. They conclude that molecular changes during fossilization likely pushed the beetles' coloring toward the red end of the color spectrum, turning a normally yellow beetle more orange, for example.
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