Butterflies in Panama Use Special Ears to Escape Bats

Recently discovered butterflies in Panama have ears on their wings that allow them to hear the ultrasonic noises emitted by bats to help the mammals locate their prey, according to Canadian researchers. When exposed to ultrasonic sounds similar to those emitted by bats, the butterflies exhibit bat-evasive behavior, the team reports in today’s Nature.

The newly discovered butterflies are night fliers--as were ancient butterflies--and apparently have developed the ultrasonic ears as a defensive weapon. Modern species have shifted to daytime activity primarily as a response to the nighttime predation of bats.

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--Compiled by Times medical writer Thomas H. Maugh II