Fossilised wing structures from China’s Inner Mongolia Autonomous Region reveal that insects were communicating through ultrasonic frequencies 165 million years ago. Researchers used lasers, AI, and computer simulations to reconstruct the prehistoric sounds, proving that ancient insect acoustics evolved long before the emergence of modern bats.
Capital Normal University Research on Ningcheng County Fossils
Prehistoric ecosystems carried an acoustic world far more complex than scientists previously understood. By examining 20 forewing specimens belonging to nine species of male katydids from the Yanliao Biota in Ningcheng County, researchers from Capital Normal University and collaborating teams have pulled back a 165-million-year curtain on Middle Jurassic soundscapes. Research on Jurassic-era fossil katydids from Ningcheng County, North China’s Inner Mongolia Autonomous Region, has provided the first evidence that insects capable of ultrasonic communication existed 165 million years ago, during the Middle Jurassic, a researcher at the Capital Normal University (CNU) told the Global Times on Thursday. The research was conducted by the CNU in collaboration with multiple research teams in China and abroad.
The findings, were published online in the Proceedings of the National Academy of Sciences of the US on Wednesday. The study has provided the first clear evidence that the evolutionary origins of ultrasonic communication in insects predated the emergence of bats, placing them more than 100 million years earlier than the bats of the Eocene epoch. The academic community had long believed that ultrasonic communication in insects evolved as an adaptation to predation by bats. This finding challenges a major idea about ultrasound, meaning bats could not have been the original reason for all insect ultrasonic communication.
Reconstructing Jurassic Sound Through Lasers and Machine Learning
Jiulongshan Formation Wing Specimens and Stridulation Analysis
Scientists have used AI, lasers and fossilised wings to reconstruct the likely sounds of insects that lived 165 million years ago, revealing a surprisingly complex Jurassic soundscape. The research team combined laser measurements, wing morphology analysis, resonance simulations, and machine-learning models to turn static fossils into dynamic acoustic predictions. Machine-learning models analysed wing shapes and helped predict possible call patterns, while scientists combined those predictions with laser measurements and computer simulations of wing vibrations. AI did not “record” a Jurassic sound, but instead helped reconstruct what the sound was most likely to have been.
That sound production relied on stridulation, a process known as rubbing one wing against another. As researchers selected 20 forewing specimens discovered in China’s Jiulongshan Formation in Inner Mongolia and compared them with nearly 100 living insect species, they mapped out the structural physics behind the noise to understand how wing structures are connected to sound production.
Frequency Ranges and the Discovery of Sigmaboilus peregrinus
Dr Jun-Jie Gu and Sichuan Agricultural University Acoustic Analysis
The breakthrough comes from Dr Jun-Jie Gu of Sichuan Agricultural University and his colleagues. The acoustic analysis revealed a distinct split in the calling frequencies of the nine fossil species examined. The calling frequencies of the nine fossil insect species ranged from 5 to 20.5 kilohertz (kHz). Five species produced low-frequency pure tones in the 5-7 kHz range, while the remaining four occupied the medium- to high-frequency range of 8-20.5 kHz.
Most of the ancient ensiferans studied appear to have produced calls around 5 kHz. One particular species, Sigmaboilus peregrinus, may have called above 20 kHz, reaching the ultrasonic range that humans cannot normally hear, confirming that insects capable of true ultrasonic communication already existed during the Middle Jurassic.
“The study allows us to hear insect calls from the Jurassic period across 165 million years, proposes a new theory of two-way acoustic selection between insects and mammals in the Mesozoic Era, and provides a more complete picture of the co-evolution of hearing and sound production in terrestrial animals,” said Ren Dong, co-author of the paper and professor at the CNU.
Broader Implications for Mesozoic Ecosystems
Mesozoic Era Evolutionary Pressures and Mammal Predation
With bat predation ruled out as the initial driver for ultrasonic calls, researchers are looking toward other evolutionary pressures in the Mesozoic era. Researchers believe early mammals, predators and competition between insect species could have influenced how these sounds evolved in Jurassic forests. Scientists also hope to paint a picture of a whole lost world through AI and modelling, potentially offering a new way to hear worlds that are millions of years gone as more fossils have the potential to tell their story.
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