Moths have evolved thick ‘stealth coats’ to stop hungry bats from hearing them fly, claims scientist
Moths have evolved thick ‘stealth coats’ to stop hungry bats from hearing them fly, one scientist has claimed.
Moths are a mainstay food source for bats which use biological sonar to hunt their prey, according to Daily Mail.
While some moths have evolved ears that detect the ultrasonic calls of bats, many types of moths remain deaf.
Thomas Neil from Bristol University found the insects have developed what he calls a ‘stealth coating’ that serves as an acoustic cover.
Dr Neil says moths have evolved passive defences over millions of years to resist their primary predators.
His research has focused on how fur on a moth’s thorax and wing joints reduces how audible they are to bats.
‘Thoracic fur provides substantial acoustic stealth at all ecologically relevant ultrasonic frequencies,’ said Dr Neil.
‘The thorax moth fur acts as a lightweight porous sound absorber, facilitating acoustic camouflage and offering a significant survival advantage.’
Removing the fur from the moth’s thorax increased its detection risk by as much as 38 per cent.
Dr Neil used acoustic tomography to quantify the echo strength of two deaf moth species that are subject to bat predation and two butterfly species that are not.
In comparing the effects of removing thorax fur from insects that serve as food for bats to those that don’t, Dr Neil’s research team found that thoracic fur determines acoustic camouflage of moths but not butterflies.
‘We found that the fur on moths was both thicker and denser than that of the butterflies, and these parameters seem to be linked with the absorptive performance of their respective furs,’ Dr Neil said.
‘The thorax fur of the moths was able to absorb up to 85 per cent of the impinging sound energy.
‘The maximum absorption we found in butterflies was just 20 per cent.’
Dr Neil’s research could contribute to the development of biomimetic materials for ultrathin sound absorbers and other noise-control devices.
N.H.Kh