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Well, let’s say you’re a tiny insect, crawling along a plant, looking for a mate. You can’t see them, they can’t see you, but you want to let your potential mate know that you’re nearby – so what do you do? Well, if you’re a thornbug, you can send this signal. I’m Jim Metzner, and this is the Pulse of the Planet.
ambience: Male thornbug advertisement signals/ female thornbug duet
Rex Cocroft is an assistant professor of biology at the University of Missouri. With the help of a sensitive microphone, he’s been able to listen in on the signals that thornbugs make before they mate. These sounds can’t be heard in the air; they’re vibrations transmitted through the plant itself.
“What we are hearing right now is a male thornbug, calling in response to the signal of a receptive female. So, the loud frequency down sweep that you’re hearing is the male’s advertisement signal. That is, the signal he tries to illicit a response from a female and then what you’re hearing after that is a low, rattley female call. So when males are searching for mates, they’ll fly to plant and give one of these wonderful calls and if there is a receptive female on the plant, then she may produce a call of her own, right after the male’s signal. And then when he hears that, his behavior changes completely. Instead of then flying off to the next plant, he will stick like glue to the plant he is on and start calling much more frequently. And then the female answers, essentially each of his calls. And he then begins trying to locate the female. He’ll get closer, then he’ll stop . . . he’ll call again, he’ll get another call from her, and eventually gets closer and closer. He’ll get right up to the female and at that point, typically they’ll mate.”
Pulse of the Planet is presented by the National Science Foundation. I’m Jim Metzner.
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