Stories / Transcript

Analysis: Experiments find gnats respond to the human voice

September 25, 2003 from Day to Day

MIKE SHUSTER, host: In his poem "To Autumn," the great poet John Keats took notice of the gnats. He wrote that, "in a wailful choir, the small gnats mourn." But they also respond to the sound of a human voice, as radio producer Jeff Rice discovered when he visited an entomologist who provided the music.

(Soundbite of humming)

JEFF RICE reporting:

That's Dr. Ian Robertson. He's an entomologist at Boise State University. A little while ago, we went down to the river to hum to gnats.

(Soundbite of humming)

Dr. IAN ROBERTSON (Boise State University): They'll just think I'm crazy.

RICE: He was performing an experiment to study the sexual rituals of these insects.

(Soundbite of humming)

Dr. ROBERTSON: Males gather together in big masses, usually around water. That's near where they emerge. When a female arrives near the swarm, males can hear the wing beat of the female. They're sensitive to that sound she makes.

RICE: We can play the role of the female gnat because...

(Soundbite of humming)

Dr. ROBERTSON: As far as I know, the midges and gnats all have this special organ on the male's antenna. It's known as a Johnston organ. It's an enlargement of one of the antennal segments. And their antennae are very feathery, and that picks up the vibrations, and then it's translated to this organ at the base of the antenna, which then amplifies it.

And essentially they're hearing the vibrations in the air. And you definitely know you're having an effect because as soon as you stop, the ball goes back to its normal orientation, normal movement. And then when you hum again, they speed up and they come towards you. And that's because the males are being fooled into thinking that a female is nearby.

RICE: It's nothing short of beautiful. Clouds of gnats shift direction like flocks of birds, then they become liquid; they move and surge almost like a tide lapping against the shore. It's not long before we are controlling whole fields of them. And it gives me an idea. If this works with a couple of people, think of the possibilities.

(Soundbite of humming)

RICE: So I called up my wife, who has a choir, and asked her to join us by the river.

Hit it.

(Soundbite of choir humming)

RICE: So did we attract any gnats, did you notice?

Unidentified Man: I had one fly up my nose.

(Soundbite of laughter)

RICE: For DAY TO DAY, I'm Jeff Rice.

SHUSTER: This is DAY TO DAY. I'm Mike Shuster.