As anyone with a dog whistle knows, the range of human hearing is hardly anything to get excited about. But when it comes to picking up extremely high frequencies, there’s one particular creature that even dogs can’t compete with.
The animal is the greater wax moth, Galleria mellonella. And get this — it can hear frequencies as high as 300 kHz!
For contrast, humans max out at 20 kHz, and dogs at 40 kHz. The harbour porpoise can hear frequencies up to 110 kHz, while bottlenose dolphins can pick up sounds as high as 150 kHz (which they use for echolocation). Even other moths, like some located in North America, can “only” hear up to 150 kHz.
Oh, and there is another animal to consider: The bat. Their echolocation calls can reach upwards of 212 kHz.
And indeed, it’s because of bats that the greater wax moth can hear so well. These two species are currently engaged in an auditory arms race — and the moth is winning. These moths can tell when they’ve been hit by an echolocation pulse, and they make evasive maneuvers when it happens. This has resulted in increasingly stronger hearing over time; it’s classic Darwinianism at work.
But here’s where Darwin gets a bit unorthodox. As new research from Hannah Moir and colleagues at the University of Strathclyde in Glasgow has shown, Galleria mellonella seems to have evolved a pre-adaptation in response to the bat’s hunting technique.
Which doesn’t make a lot of sense given what we know of selectional processes. But Moir has two theories.
First, it’s possible that bats are producing frequencies that are higher than can be recorded. Microphones tend to flake out when sounds exceed 150 kHz, and bat calls are hard to capture.
Second, the adaptation could be an accident. But that seems unlikely given that evolution doesn’t tend to reinforce “accidental” traits over time when there's a total lack of selective pressures to uphold those genetic characteristics.
Regardless, bats have some evolving to do.
Read the entire study at Biology Letters: “Extremely high frequency sensitivity in a ‘simple’ ear.”
Image: Luis Carlos Torres/Shutterstock. Moth image via.