February 7, 2012
Researchers Recreate Fossil Cricket Love Song
An international team of scientists took it upon themselves to recreate the love song of an extinct cricket that lived more than 160 million years ago during the Jurassic Period.
The song was reconstructed using microscopic wing features on a fossilized bush cricket (Archaboilus musicus) found in northeast China. The call of the Jurassic cricket was simple, pure and capable of traveling long distances in the night, scientists noted.
The reproduced sounds are actually the mating call of the “primitive” insect, whose modern descendants are also known as katydids. The “exceptionally” well-preserved fossilized remains were discovered by Chinese scientists from Capital Normal University in Beijing.
Jun-Jie Gu and Professor Dong Ren, yearning to know how their fossil would have sounded when alive, contacted Dr. Fernando Montealegre-Zapata and Professor Daniel Robert of Bristol University in the UK, both experts in the biomechanics of singing and hearing in insects. The group also teamed up with Dr. Michael Engel of the University of Kansas, USA, a leading expert on insect evolution.
The Chinese team provided an exceptionally detailed bush cricket fossil with well-preserved wings, measuring three-quarters of an inch long, allowing scientists to recreate for the first time the features that would have produced sound when rubbed together.
The researchers said the resulting sounds are “possibly the most ancient known musical song documented to date.” They said the call should be imagined against a busy backdrop of waterfalls, wind, the sound of water coursing through streams and other amphibious creatures and insects serenading their mates.
The researchers, publishing their study in the US journal Proceedings of the National Academy of Sciences, examined the anatomical construction of the fossil´s song apparatus, and compared it to 59 living species of katydids. They concluded that the 165-million-year-old cricket must have produced musical songs, broadcasting pure, single frequencies.
Montealegre-Zapata, using biomechanical principles he discovered years ago, established that this extinct cricket sang a tone pitched at 6.4kHz and each tone lasted roughly 16 milliseconds. This information gave the scientists enough data to acoustically reconstruct the song itself.
“This discovery indicates that pure tone communication was already exploited by animals in the middle Jurassic, some 165 million years ago. For Archaboilus, as for living bush cricket species, singing constitutes a key component of mate attraction,” said Robert. “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.”
“Using a low-pitched song, A. musicus was acoustically adapted to long-distance communication in a lightly cluttered environment, such as a Jurassic forest,” added Montealegre-Zapata. “Today, all species of katydids that use musical calls are nocturnal so musical calls in the Jurassic were also most likely an adaptation to nocturnal life.”
“Being nocturnal, Archaboilus musicus probably escaped from diurnal predators like Archaeopteryx, but it cannot be ruled out that Jurassic insectivorous mammals like Morganucodon and Dryolestes also listened to the calls of Archaboilus and preyed on them,” he said.
“This Jurassic bush cricket 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. It also suggests the evolutionary mechanisms that drove modern bush crickets 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,” said the researchers.
On the Net:
- Bristol University
- Capital Normal University
- University of Kansas
- Proceedings of the National Academy of Sciences