Newly Discovered Insect 'Sings' with Highest Ultrasonic Calls in the Animal Kingdom

Deep within the rainforests of South America there live three species of insect with the highest ultrasonic calling songs ever recorded in the animal kingdom. Recently discovered, these species are shedding light on the amazing abilities of insects.

Katydids, also known as bushcrickets, are insects that are known for their ability to use acoustic communication. Male insects produce sound by rubbing their wings together in order to attract females for mating. Yet the ones recently found in the rainforests of South America, which have a new genus by the name of Supersonus, take this acoustic communication to a new extreme. They can produce the highest ultrasonic calling songs known in nature, with males reaching 150 kHz. To put that in perspective, most calling frequencies used by katydids range between 5 kHz and 30 kHz, and normal human hearing range ends at around 20 kHz.

"To call distant females, male katydids produce songs by 'stridulations' where one wing (the scraper) rubs against a row of 'teeth' on the other wing," said Fernando Montealegre-Z, one of the researchers, in a news release. "The scraper is next to a vibrating drum that acts like a speaker. The forewings and drums are unusually reduced in size in the Supersonus species, yet they still manage to be highly ultrasonic and very loud."

In fact, these new species have lost the ability of flight due to their reduced wing size. This could be the reason why they evolved the ability to use ultrasonic frequencies-as a way to avoid being detected by predators while still being able to communicate with one another. Most bats detect their prey's movements using echolocation, but can also eavesdrop and detect the calls of katydids and frogs. That's why most rainforest katydids reduce the time they spend singing. Yet by singing at extreme ultrasonic frequencies, these insects can make it harder for bats to detect them.

"These insects can produce, and hear, loud ultrasonic calls in air," said James Windmill, one of the researchers, in a news release. "Understanding how nature's systems do this can give us inspiration for our engineered ultrasonics."

The findings are published in the journal PLOS One.