Airdate: Jul 29, 1998
Scientist: Mark Hostetler
WINDSHIELD INSECTS-Moths and the Moon
The truth about why moths are attracted to light bulbs.
Moonlight - and Your Carambience: CricketsHere's a program from our archives.This week we've been hearing about one of the more unfortunate interactions between man and insect- those splats you find on your car windshield after a drive through the country. But the insects you'll run into after an evening drive are not the same as the ones you'll encounter during the day. And the reason why may surprise you. I'm Jim Metzner, and this is the Pulse of the Planet.Mark Hostetler is the author of a guide which identifies insects from the splat patterns they make on your windshield. He tells us that for some nighttime insects, the headlights of your car are an irresistible optical illusion.Hostetler: Driving at night, you tend to run into certain species that are attracted to the headlights on our cars. And the most notorious one is the moth. You know people always ask 'why do moths fly around my light bulb on the porch?' And the explanation is: moths use the moon for navigation, when they're flying across the landscape. So they fly at a constant angle to moonlight, and the moonlight tends to come in parallel, because the moon is so far away. However, if you bring in something that looks like moonlight, like light bulbs, light coming from light bulbs, right down to them, they actually think they went past the moon, so they circle back, and then they circle again and then pretty soon they just keep going round in circles, and they go right around what they think is the moon, so they're very confused. It's one of those things that for millions of years the moon's been the only bright object in the sky until humans came around and invented light bulbs, electricity.For transcripts of this and other programs in our series, please visit our web site at www.pulseplanet.com.We've been listening to a program from our archives. If you want to hear more, check out our podcast. I'm Jim Metzner and this is the Pulse of the Planet.