Tiny Katydid's Song as Loud as a Power Saw

A small insect called the katydid is capable of making quite a big noise at ultra-high frequencies.

Katydid songs have been recorded at at sound levels around 110 decibels -- comparable to that of a power saw.

The insect's song has been documented in a paper describing how the tiny creatures make such big sound.

Researchers used hyper-sensitive sound recording equipment and high-speed video to record a recently-discovered species of katydid, Arachnoscelis arachnoides, making noise. They found that male katydids sing their song at 74 kilohertz, a high frequency reached by using rapid wing movement and elastic energy.

To make noise, the insect scrapes one of its wings against a row of "teeth" on its other wing. The slow motion of the wings rubbing together is amplified by the scraper and file-teeth encounter.

The katydid research was co-authored by an undergraduate researcher at University of Lincoln, Ben Chivers.

"The file and the scraper are the first step in sound production and my undergraduate research on nearly 50 species of katydids revealed a correlation between the quality of the acoustic signal produced and the structure of the stridulatory file," Chivers said. "Arachnoscelis arachnoides exhibits a file with a tooth distribution consistent with the broadband (low quality) calls associated with singing in the high ultra-sonic range."

Fernando Montealegre-Zapata, who advised Chivers during his research said:

"We have evidence that ultrasonic signaling in A. arachnoides involves sound levels of about 110dB which are considered unusually loud for such a small insect. The mechanism of scraper distortion is therefore a good candidate to be responsible for the high sound intensity observed in the calls: at such ultrasonic frequencies, you need to be loud to be detected by females."

The study is published in the Journal of Bioacoustics.