Deaf Moths Use “Acoustic Camouflage” to Evade Echolocation

According to new research, the fuzz you see on the chest of moths is specifically designed to muffle sound and protect them from bats.

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Nov 6 2018, 7:30pm

Many moths are deaf, which is dangerous considering the fact that their main predators are bats, which use echolocation to hunt. If a moth doesn’t know how much noise it’s making and at a given, how should can it know it’s at risk?

According to researchers from Bristol University in the United Kingdom, who published their findings in the Journal of the Acoustical Society of America (ASA) this month, there’s a simple explanation: deaf moths often grow fur designed to muffle the sounds they make.

Nocturnal moths are often hunted down by bats which use echolocation, or the process of using sound to map and navigate the area around you. This means that if the bats can’t hear a moth, it has a better chance at survival.

Certain nocturnal, deaf moths, like the Madagascan Bullseye moth, have taken advantage of this circumstance by developing fur on their thoraxes, a chest-like space on certain species that’s between the neck and abdomen. Compared to other insects, such as butterflies, moths have fur with far superior sound-muffling capabilities.

"The thorax fur of the moths was able to absorb up to 85 percent of the impinging sound energy,” lead researcher Tom Neil said in a press release. “The maximum absorption we found in butterflies was just 20 percent."

There are certain species of moths that have ultra-sensitive hearing, with tiny eardrums, that allow them to detect extremely subtle movements of bats. However, that’s on the extreme end of the spectrum, and most moths are living in a world without noise, fighting to survive.