Life - Jurassic katydid sings out after 165 million years

Most sounds vanish forever after a few seconds, but not the calls of a Jurassic katydid. After examining the sound-making structures on its exceptionally preserved fossil wings, biologists have recreated its musical calls.

Katydids, or bush crickets, make sounds by rubbing the edge of one wing against a series of teeth on the other. The shape of the teeth determine whether the calls are complex sounds containing many frequencies, or pure tones.

The newly discovered fossil katydid (Archabollus musicus) has wing structures that show it "sang" a pure tone at 6.4 kilohertz, within the human audible range, says Fernando Montealegre-Zapata at the University of Bristol, UK.

Sounds at that frequency can travel long distances – useful for night-time communications. Nocturnal mammals cannot easily work out the source of pure tones, which would have helped the katydids escape these predators, says Montealegre-Zapata.

Jurassic forests were probably noisy places at night – there is evolutionary evidence that frogs were croaking by this time, and fossils suggest some Jurassic dinosaurs were nocturnal.

Journal reference: Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.1118372109

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