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Hossein Rajaei

Earliest evidence of butterflies poses an intriguing mystery

Picture a butterfly. Is it on a flower sucking up sweet nectar with its tonguelike proboscis? Well, hold that thought. Thanks to the earliest butterfly fossils yet discovered, researchers now estimate proboscis-sporting butterflies were around well before flowering plants. After digging the delicate relics out of rocks in northern Germany, researchers examined the scales that cover butterfly and moth wings, bodies, and legs (pictured) under a powerful microscope. Some scales were solid and decorated with a herringbone pattern. That indicated its owner had jaws to chew food because most butterfly families with solid scales have mandibles. But other scales researchers inspected were hollow with markings that distinctly resemble those of a living class of the insects that uses its proboscis to eat. Ancient phytoplankton and pollen grains nestled in the sediment date the early butterfly fossils to roughly 200 million years ago, researchers report today in Science Advances, whereas flowering plants began growing across the landscape only about 140 million to 160 million years ago. So, what good was a proboscis if not for slurping up flowers’ sugary goodness? Instead of nectar, researchers suggest the appendage likely helped the winged insects avoid becoming dehydrated in the hot and arid climate of the time by getting sustenance from another source: sweet secretions beaded up into droplets on seed-bearing—as opposed to flowering—plants.