It's known as the cocktail-party problem: in the cacophony of sound made by insects in a spring meadow, how does one species recognize its own song?

Insects such as the tree cricket solve this problem by singing and listening at a single unique pitch.

But if that's the case, U of T Scarborough researchers wondered what happens when the temperature changes, because that affects the frequency of the tree cricket's song. The higher the temperature, the higher the pitch.


A male tree cricket (right) sings with his wings up, as a female standing next to him. Credit: Ken Sproule

Natasha Mhatre, a postdoctoral fellow in the lab of Biological Sciences Prof. Andrew Mason, says it's all in their ears.

"When the temperature goes up, the males' wings move faster, so the frequency goes higher," says Mhatre. "The females also need to tune their ears so they can listen to that frequency."

As temperature changes, tree cricket ears adjust at a cellular and therefore mechanical level to match the changing frequency of the song. Mhatre conducted the study with Mason and Gerald Pollack, a McGill University emeritus professor who also works in the Mason lab.

To show this, they used laser Doppler vibrometry, which observes the vibration of any structure, even microscopic cricket ears. They also recorded the reactions of nerve cells to different song frequencies.

The study has been published in the journal Biology Letters.

source: University of Toronto