New fossil analyses of large insects known as Kalligrammatid lacewings that lived in Eurasia during the mid-Mesozoic Era some 125 to 165 million years ago have revealed that these are surprisingly similar to modern butterflies.
Kalligrammatid lacewings likely served as important pollinators during mid-Mesozoic times, using mouthparts that were strikingly similar to the elongated, tubular structures that modern butterflies have to sip nectar-like fluids from flowering plants, the researchers said.
What is more, their wings bore eyespot patterns that closely resemble those found on some butterflies today, which may have helped to distract or deter potential predators, said the study published in the journal Proceedings of the Royal Society B.
In modern butterflies with eyespots, the dark center of the mark is formed by a concentration of the pigment melanin.
A sensitive chemical analysis indicated that the Kalligrammatids, too, had melanin at the center of their eyespots.
"That, in turn, suggests that the two groups of insects share a genetic programme for eyespot production," said lead researcher Conrad Labandeira from Smithsonian Institution National Museum of Natural History in Washington, D.C.
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Paleobiologists have known for more than 100 years that Kalligrammatid lacewings lived in Eurasia during the Mesozoic.
But the insects have remained largely enigmatic until recent discoveries of well-preserved fossils from two sites in northeastern China.
"Various features of the mouthparts all indicate that these things were sucking fluids from the reproductive structures of gymnosperm plants," Labandeira said.
Although the lacewings' mouthparts were strikingly similar to those of modern butterflies, there were no nectar-producing flowers in these Mesozoic forests.
Paleobotanist David Dilcher of Indiana University, a member of the research team, said that like many Mesozoic insects, Kalligrammatids would have fed on sugary pollen drops produced by seed plants, transferring pollen between male and female plant parts as they did so.
A now-extinct group of plants called bennettitaleans, whose deep, tubular reproductive structures may have been accessed by kalligrammatid proboscises, likely was the primary food source for the lacewings, the study said.