How the Praying Mantis Hears
The mantis is the only animal known to listen to its world through one ear; what it often hears is bats zeroing in to eat it
Not So Deaf After all
Scientists long thought that praying mantises were deaf, but now biologists know that the insects have a single ear that enables them to pick up sounds far beyond the range of human hearing.
When sitting still to wait for prey, mantises often mimic leaves or twigs. According to University of Maryland neuroscientist David Yager, mantises on the move also can do an excellent imitation of a fighter jet. When a flying mantis is trying to escape from a hungry bat, one of its primary nighttime enemies, it can suddenly pull up in midair, turn to the side and drop into a power dive similar to that of a military pilot avoiding an adversary.
"It's not just a fall," Yager says. "They go faster as they go down." Sometimes a bat can follow; other times, it has to give up pursuit. When a bat stays on a mantis’ tail, the insect may hit the ground as a last resort. Being small and agile, it survives the crash. Without the ability to hear the bats, no mantis would stand a chance.
Why Is the Mantis Praying?
There are some 2,300 mantis species worldwide, including about 20 in the United States. Most are so-called "sit and wait" predators that feed on moths, crickets and other insects, keeping their front legs flexed so that they look like they are praying. In fact, they are poised for a sudden, blurring extension to catch food species that pass by. Some bigger mantis species can snag even a small lizard or hummingbird.
How Mantises Hear
Mantids detect attacking bats by picking up the mammals' high-frequency or ultrasonic chirps, so clearly the insects aren't deaf, even though they seem earless. Yager found their secret while a graduate student in the late 1980s, when he discovered that most praying mantis species have single ears deep in the centers of their thoraxes, or chest segments. "The ear doesn’t look like any other ear," says Yager, who is studying the auditory systems of insects. "They're the only animals known to have just one ear."
Adapted from "The Better to Hear You With" by Doreen Cubie, National Wildlife , December/January 2010.