Fossils Replicate Mating Call

Katydids were singing pretty much the same song 55 million years ago that they do today, new fossil evidence suggests.

The katydid fossils, discovered in Denmark, represent the oldest known evidence of insects communicating by making distinct noises.

Scientists from the University of Gottingen in Germany drew their conclusions from 20,000 bushcricket, or katydid, specimens preserved in solidified ocean sediment. The fossils are described in Thursday's issue of the journal Nature.

Many of the fossils contain finely detailed impressions of the insects' wings and forelegs. They show that the prehistoric katydids were calling out to potential mates back then much as they do today -- by scraping their wings together.

From the fossils, the researchers were able to recreate the creature's tune, producing a rare sample of what earth probably sounded like long, long ago. That song will be used in exhibits in Danish museums.

"When you listen to living bushcrickets today, some of them are making two songs. They are modulating them and making pauses. We guess that these ancient bushcrickets were singing only one main tone without pauses," said Jes Rust, a professor of zoology and paleontology at Gottingen.

David Grimaldi, curator of entomology at the American Museum of Natural History in New York, said the fossils push evidence of insect communication 15 million years further into the past. Similar organs are seen in crickets trapped in 40 million-year-old amber, he said.

While the northern tip of Denmark's Jutland peninsula, where the fossils were found, is chilly and windswept today, the region was a subtropical jungle when the insects were alive.