Thus returning little information to the hungry bat:
Bats hunt at night using echolocation. The technique, which is also known as biological sonar, first evolved around 65 million years ago and enables bats to search for and find prey putting huge predation pressure on nocturnal insects. One defence that many nocturnal insects evolved is the ability to hear the ultrasonic calls of bats, which allows them to actively evade approaching bats.
Many moth species, however, cannot hear. The team of researchers from the University of Bristol wanted to investigate the alternative defences against bats that some species of deaf moths might have evolved.
Using scanning electron microscopy, the team from Bristol’s School of Biological Sciences discovered that the thorax scales of the moths Antherina suraka and Callosamia promethea looked structurally similar to fibres that are used as noise insulation, so wanted to explore whether the thorax scales of moths might be acting in some way to absorb the ultrasonic clicks of bats and dampen the echoes returning to the bat, offering the moths a type of acoustic camouflage.
The team measured that the scales on the body of a moth absorb as much as 85 per cent of the incoming sound energy and that the scales can reduce the distance a bat would be able to detect a moth by almost 25 per cent, potentially offering the moth a significant increase in its survival chances.
Dr. Thomas Neil, Research Associate from Bristol’s School of Biological Sciences and lead author, said: “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.
University of Bristol, “Deaf moths evolved noise-cancelling scales to evade predators” at Phys.org
Schoolbook evolution stories would tell us that the moths evolved that ruse as a random mutation acted on by natural selection—as if it were some kind of a lucky number they might have come up with in 65 million years. Not so fast. It’s a hitherto unknown system that will need a considerably more detailed explanation than that. Evoking “natural selection” as a mantra doesn’t work like it used to, back when we knew so much less.
Hat tip: Philip Cunningham who writes, “Got to love how ‘evolution’ can out-engineer our best engineers time after time. 🙂 ” Presumably, that’s the advantage of mindlessness. It comes up with the sharpest ideas.