Moths avoid bats. It’s nothing personal, just an understandable desire not to get devoured. In the perpetual evolutionary arms race between the nocturnal creatures, moths seem to have developed ears for the sole purpose of hearing bats’ echolocation cries—because if you want to avoid becoming someone’s midnight snack, getting wind of their approach is key.
Do you remember that part in Dead Poets Society where Robin Williams asks his students why language was invented? “To communicate,” suggests one. “No!” he replies, “To woo women.” Well, humans aren’t the only mammals that have a way of making everything about sex. Until recently, scientists believed that moths could hear sounds, but not produce them. Turns out, though, that most male moths make sounds when they want to engage in a little nookie. And not just any sounds, either—their calls are distinctly bat-like.
A sensory physiology researcher from the University of Southern Denmark, along with colleagues from the University of Tokyo, has been studying two different species of moths to find out exactly how sound is used for courtship. It’s not quite the same for everyone.
In the Asian corn borer, a moth much prettier than it sounds, males make a call that’s indistinguishable from a bat’s hunting cry. Females instinctively freeze at the sound, making it harder for the bats to find them. But in Asian corn borer society, immobility apparently equals consent, because when a female holds still, that’s when the magic of reproduction can happen.
On the other hand, male Japanese lichen moths also make sounds like bats gone a’hunting. But the females of that species aren’t fooled—they can tell the difference between a bat and a suitor. The sound the males make, then, has evolved into a specific mating call.
“The acoustic communication between bats and moths is a textbook example of the interaction between predator and prey,” says Annemarie Surlykke, the researcher from Denmark. “However, our studies show how such a system can evolve, so also moths use their ability to hear and produce sounds to communicate sexually and that they have developed many different ways of doing it. It is a beautiful example of evolutionary diversity.”
If you were wondering how moths can make sounds like bats without attracting their mortal enemies, the key seems to be volume. Moths essentially whisper their calls while only inches apart, whereas bats are pretty much just screaming through the night sky. Spooky! Since we humans aren’t equipped to hear any of it, you’ll just have to imagine what sweet nothings moths murmur to one another.
Source: Science Daily