Listen to the Newly-Decoded Song of a 165 Million Year Old Cricket

Back in the Jurassic period, around 165 million years ago, ancient insects were some of the first animals to produce sounds by stridulation, or the rubbing of body parts together like a modern cricket. Paleontologists know this to be the case thanks to the preservation of stridulation structures in the fossil record. But what hasn’t been known was what they actually sounded like.

That’s changed thanks to an international group of paleontologists, who reconstructed a mid-Jurassic bushcricket’s song by comparing the song-producing structures of a well-preserved fossil to living species. Okay, so the single-tone notes aren’t exactly an opus. But 165 million years ago, they still served their purpose: attracting mates.

"This discovery indicates that pure tone communication was already exploited by animals in the middle Jurassic, some 165 million years ago," researcher Daniel Robert, of the University of Bristol, said. "Singing loud and clear advertises the presence, location and quality of the singer, a message that females choose to respond to – or not. Using a single tone, the male’s call carries further and better, and therefore is likely to serenade more females. However, it also makes the male more conspicuous to predators if they have also evolved ears to eavesdrop on these mating calls."

A group of Chinese paleontologists, including lead author Jun-Jie Gu of Capital Normal University in Beijing, were first to find the fossil of a new bushcricket species, which has since been named Archaboilus musicus. They contacted Robert and Dr. Fernando Montealegre-Zapata, both experts on the biomechanics of insect singing at Bristol, and Dr. Michael Engel of the University of Kansas, who’s background is in insect evolution. The whole team published a paper in PNAS today that suggests that the Jurassic environment was a noisy one.

Montealegre-Zapata was the one to decode the actual tones produced by A. musicus’ wings, which were extremely well-defined in the Chinese fossil. Based off of calculations he’d previously made regarding the production of sound by stridulation, Montealegre-Zapata stated that the cricket produced a 6.4kHz tone that lasted 16 milliseconds. That information was enough to reconstruct the song, which is likely the oldest known vocalization of this type.

“This Jurassic bushcricket thus sheds light on the potential auditory capacity of other animals, and helps us learn a little more about the ambiance of a world long gone," Montealegre-Zapata said. "It also suggests the evolutionary mechanisms that drove modern bushcrickets to develop ultrasonic signals for sexual pairing and for avoiding an increasingly relevant echolocating predator, but that only happened 100 million years later, possibly with the appearance of bats.”

That might be one reason why the song seems so simple today: A. musicus hadn’t been pressured, by either predation or sexual selection, to develop anything more complex. In that sense, that this cricket’s song may be a very early form of insect vocalization, it’s a truly fascinating discovery.