Transcript:

Tiger Moths - Jamming SonarHere's a program from our archives.ambience: Tiger mothWhen a Tiger moth hears a bat in the vicinity, it produces this sound. Scientists think that it may be a kind of insect battle cry to help ward off the predator bat. I'm Jim Metzner, and this is the Pulse of the Planet.This high frequency call has been slowed down thirty times so that we can hear it.Conner: Well moths have two lines of defenses. The first is that they have wonderful ears. They can hear the bats coming.Bill Conner is a Professor of Biology at Wakeforest University in North Carolina.Conner: They go through a series of evasive maneuvers: loops, spirals and power dives designed to evade the bat. But some moths do more than just evade bats. Some moths talk back to bats. They produce high frequency clicks in response to the echolocation cries of bats. And there are two theories about what these high frequency clicks are for. One is that they are jamming the echolocation sonar of the bat. In this case the clicks would be perceived as multiple echoes which would give the bat multiple acoustic images. It wouldn't be able to tell which one is in fact the moth so it would veer away.The sound might also be a message to the bats that they'd do well to find dinner elsewhere. Tiger moths feed on toxic plants which give them an unpleasant taste.Conner: This works the same way that the bright coloration works in these moths. And they can produce the high frequency sounds, the bats can hear them and then learn that these insects are in fact poisonous and thereafter avoid them.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.