One hundred and sixty-five million years ago, China’s forests were filled with the baritone serenades of male katydids. By analyzing the fossilized wings of an extinct species named Archaboilus musicus, researchers have reconstructed its acoustic signals. Their findings appear here in The Proceedings of the National Academy of Sciences. (Jun-Jie Gu, of Capital Normal University in Beijing, and Fernando Montealegre Zapata, of University of Bristol, led the research team.)
According to the article, most (though not all) katydid species alive today have asymmetrical forewings. Males in search of females produce noisy calls across a range of frequencies by scraping a toothed vein, called the stridulatory file, on the left wing across another vein (the plectrum) on the right wing.
A. musicus, in contrast, had large symmetrical forewings (each with a stridulatory file) that worked together to produce pure-tone “musical” songs at a low frequencies that could be heard over a long distance close to the ground. Like extant katydids which make pure-tone music, A. musicus probably did its serenading at night, the article states.
“In the darkness of the Jurassic forest, A. musicus surely experienced the dilemma of singing loud and clear, while simultaneously attempting to avoid nocturnal predators,” the researchers add. “We cannot rule out the possibility that Jurassic mammals (e.g. Morganucodon and Dryolestes) might have been predators of these insects, as they were able to hear sounds in the range of frequencies used by A. musicus.”
In a commentary for PNAS, University of Bonn paleontologist Jes Rust praised the research for showing “the great potential of paleoacoustic studies.” According to Rust, “Their results considerably enrich our imagination of Jurassic ecosystems, which is usually dominated by the popular dinosaurs. However, whereas these roaring pop stars have left the stage, the background vocals of insect ‘choristers’ are still there.”