Moths increase their chance of avoiding hungry bats by mimicking the sounds of a bad-tasting cousin, according to a study published this week.

Researchers at Wake Forest University in North Carolina published a study in the May 29 issue of the Proceedings of the National Academy of Sciences showing definitive proof of how animal species use acoustic mimicry as a defensive strategy.

In response to the sonar bats use to locate prey, tiger moths make ultrasonic clicks using a set of paired structures called tymbals. Many species of this moth use the clicking sound to warn the bats of their bad taste, but the researchers found other species have learned to closely mimic those high-frequency sounds.

"We found that the bats do not eat the good-tasting moths that make the similar sounds," said doctoral student Jesse Barber, who has worked on this research for four years.

Barber and professor of biology William Conner trained free-flying bats to hunt moths in view of two high-speed infrared cameras to record the interactions between predator and prey.

All of the bats quickly learned to avoid the bad-tasting moths after they were first offered them, learning to associate the noise they made with their taste. They also avoided normally appetizing moths that were able to reproduce similar sounds. The bats ate other moths of similar size that did not emit the sounds.

The bat reactions are similar to the way birds avoid butterflies that resemble the unpleasant tasting monarch, and researchers say acoustic mimicry has been anecdotally observed in animals such as snakes, owls and bees.