Evidence of this ability was first uncovered in 2009, by a group led by Aaron Corcoran, a wildlife biologist who was then a PhD student at Wake Forest University. “It started with a question has been out there for a while, since the 1960s—why do some moths produce clicking sounds when bats attack them?” Corcoran explains.
Scientists knew that most species of tiger moths that emitted ultrasonic clicking sounds did so to signal their toxicity to bats—similar to how, for example, poison dart frogs are brightly colored so that predators can easily associate their striking hues with toxic substances and learn to look elsewhere for food. This particular species, though, emitted about ten times as much sound as most moths, indicating that it might be serving a different purpose entirely.
To learn more, he and colleagues collected trigona moths, put them in a mesh cage, attached them to ultra-thin filaments to keep track of their survival, and introduced brown bats. “If the sounds are for warning purposes, it’s well-documented that the bats have to learn to associate the clicks with toxic prey over time,” he says. “So if that were the case, at first, they’d ignore the clicks and capture the moth, but eventually they’d learn that it’s toxic, and avoid it.”