September 19, 2010
Cricket Serenade
Tall grass and warm air surrounds the Nesbitt Biology Building at Carleton University in late summer, and is accompanied by the background sound of crickets. Locking her mountain bike at the lab door, Sue Bertram pauses to listen. “That’s a Fall Field Cricket. Sounds about the same as a Spring Field, but I know because of the time of year.”
The assistant science dean and associate science professor has listened closely to crickets for about 20 years. Courtesy of funding from the Canada Foundation for Innovation, she now has a new, electronic way of tracking what the crickets are saying.
A greenhouse-like building just outside Nesbitt holds containers full of crickets. Periodically, Bertram or one of her students will carefully scoop a male cricket out and place him in a small acoustic chamber, hooked up to a computer running special audio software. They can then track the length and the type of call, and begin answering questions about how it changes.
What happens if there is a female nearby? What if the male just won a fight with another cricket—or lost one? “On a larger scale, understanding how often a cricket calls can also give us a key to its longevity,” she says. “The so-called high-effort males may attract more mates, but they also are more prone to parasites that hone in based on the call. Do they clean themselves more frequently to defend against that?”
Tracking calling male crickets can also give a clue as to the factors influencing variation—the impact of diet, fertilizers, parasites, and predators, for example—which can help scientists understand how variation is maintained over time.
“Our electronic receiving system was just hooked up earlier this year, so we’re looking forward to the results it will bring us after a few field seasons,” Bertram says.
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