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Moths evade bats using acoustic camouflage on their wings

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Well, that serves the bats right for developing sonar: 😉

A University of Bristol team discovered that sound waves from bats that hit the fork-shaped scales found on two species of moth cause them to bend and twist, dissipating the energy. ‘Less sound is reflected back to the bat, and the moth thereby disappears or partially disappears from the bat’s sonar screen,’ explains Marc Holderied, an acoustic biologist at the University of Bristol, UK.

Anthony King, “Moths draped in stealth acoustic cloak evade bat sonar” at Chemistry World

Moth fur works, absorbing 69% of ultrasound energy, much like manufactured sound absorbers. But wings must also fly and that’s trickier:

Wings necessitate a thinner material and different strategy. The scales are less than a millimetre long and only a few hundred micrometres thick and each one resonates at a particular frequency. Added together, tens of thousands of individually tuned scales absorb at least three octaves of sound. ‘An assembly of resonators each absorb at their individual frequency, but they are then arranged in a way that they interact and collectively act as a metamaterial, creating broadband absorption,’ says Holderied.

Anthony King, “Moths draped in stealth acoustic cloak evade bat sonar” at Chemistry World

Paper. (open access)

Here’s how the basic idea of sonar-jamming fur works:

We’ll keep an eye open for vid featuring sonar-jamming wings.

Meanwhile, as before, those who want to attribute these staggeringly complex arms races to natural selection acting on random mutations (Darwinism) are facing a huge probability gap. The processes of nature can’t be both wholly blind and highly intelligent, given time limits.

Amazing. One of Nature's best tricks, which human technology rarely manages to copy, is absorbing force through reactivity instead of resistivity. When the incoming force is discombobulated, the absorber doesn't need as much strength. Simple example: Absorbing wind with leaves vs standing up to wind with a fence. polistra

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