In this composite image of a moth and a butterfly the coloured sides show the target species while the grey scale is the resultant tomographic image. This allows researchers to measure how much sound is being reflected from certain body parts.

Deaf moths versus predator bats

Some species of deaf moths have evolved a clever defensive strategy to reduce the risk of being eaten by bats, a British study has found.

Unlike other nocturnal insects, they are unable to hear the ultrasonic calls of bats, which use echolocation to detect potential prey.

Instead, they have “noise-cancelling scales” that can absorb up to 85% of the incoming energy, reducing by almost 25% the distance at which a bat would be able to find them, reports a team from the University of Bristol.

Thomas Neil and colleagues used scanning electron microscopy to study the moths Antherina suraka and Callosamia promethea and discovered that their thorax scales look structurally similar to fibres used for noise insulation.

“We were amazed to see that these extraordinary insects were able to achieve the same levels of sound absorption as commercially available technical sound absorbers, whilst at the same time being much thinner and lighter,” says Neil.

“We are now looking at ways in which we can use these biological systems to inspire new solutions to sound insulating technology and analyse the scaling on a moth’s wing to explore whether they too have sound absorbing properties.”

The findings are published in the journal Royal Society Interface.