Scientists recreate sounds of Jurassic katydid relatives from fossil wings

Researchers analyzed fossilized wings from nine species of Jurassic katydid relatives found in Inner Mongolia, dating back 165 million years. By measuring the microscopic ridges that produce sound and using computer models, they reconstructed the likely calls of these ancient insects. The study, published in PNAS, offers a glimpse into the acoustic environment of a Middle Jurassic forest.

The fossil wings preserve microscopic tooth-like ridges that functioned as sound-producing structures. When a scraper on the opposite wing rubbed across these ridges, the spacing and the vibrating wing area determined the resulting pitch. Researchers measured these features across all 20 specimens and combined the data with modern insect comparisons and evolutionary relationships to model each species' call.

Most reconstructed calls were pure tones near 5 kilohertz, comparable to living crickets. However, Sigmaboilus peregrinus produced ultrasonic signals above 20 kilohertz, well before bats existed. This finding challenges the long-held assumption that bat predation drove the evolution of ultrasonic communication in katydids, suggesting instead that early mammals or other hearing-sensitive predators may have influenced this acoustic adaptation.