Ultrasonic bat defenses are widespread in moths
Using artificial intelligence, researchers have discovered what is likely the largest animal mimicry complex on Earth, changing the way we see, or rather hear, the night sky. (Chandan Singh, CC BY 2.0)
While a clear night sky might seem quiet and peaceful to us, empty of everything but stars, this nocturnal world is filled with a high-pitched cacophony of sound just beyond our ability to hear. Bats pierce the shadows with ultrasonic pulses that enable them to construct an auditory map of their surroundings, which is bad news for moths, one of their favorite foods.
Not all moths are defenseless prey, however. Some emit ultrasonic signals of their own that startle bats into breaking off pursuit. Many moths that contain bitter toxins avoid capture altogether by producing distinct ultrasounds that alert bats to their foul taste. Others conceal themselves in a shroud of sonar-jamming static that makes them hard to find with bat echolocation.
While effective, these types of auditory defense mechanisms in moths are considered relatively rare, known only in tiger moths, hawk moths and a single species of geometrid moth. But a new study published in the journal PNAS shows that ultrasound-producing moths are far more widespread than previously thought, adding three newly discovered sound-producing organs, eight new subfamilies and potentially thousands of species to the roster.
“It’s not just tiger moths and hawk moths that are doing this. There are tons of moths that create ultrasonic sounds, and we hardly know anything about them,” said senior author Akito Kawahara, a curator at the Florida Museum of Natural History’s McGuire Center for Lepidoptera & Biodiversity.