Karen Hopkin: This is Scientific American’s 60-Second Science. I’m Karen Hopkin.
Some things are SO adorable, we say they’re cute as a bug’s ear. Of course, bugs don’t have ears. But a new study shows that orb-weaving spiders can use their webs to detect sounds. The findings are unfurled in the Proceedings of the National Academy of Sciences.
Ron Hoy: Any animal that makes sounds is likely to have an ear.
Hopkin: Ron Hoy studies neurobiology and behavior at Cornell University in Ithaca.
Hoy: …ranging all the way from tiny crickets, and flies that are even smaller than crickets, all the way through to humans of course.
Ron Miles: It’s also pretty interesting that a great many animals don’t have eardrums. But they still hear.
Hopkin: That’s Ron Miles.
Miles: The two Rons, here.
Hopkin: Ron Miles, who’s been collaborating with Ron Hoy for 30 years, is an engineer at Binghamton University…
Miles: …an hour’s drive away from Cornell.
Hopkin: Critters lacking eardrums receive audio input very fine hairs.
Miles: If you look at spiders and insects, they’re covered with hairs.
Hopkin: Because these whispy little filaments can float freely in the breeze, they’re great at sensing the air currents that comprise sound waves.
Miles: Since we knew that so many animals like small insects and spiders have hairs that can sense sound, … we were kind of wondering how would you make something that could sense sound the way that some of these small animals do.
Hopkin: A possibility appeared during an afternoon stroll.
Miles: My graduate student, Jian Zhou, was walking in our campus nature preserve one day and he noticed when the wind blew, if you look at a spider web, it moves with the wind. And he thought maybe a fine spider web or spider silk could act as a sound sensor.
Hopkin: To find out, the researchers coaxed a spider into giving them a bit of silk…
Miles: … and we played sound at a little strand of spider silk and found that when the silk is very thin, it moves with the air in a sound field amazingly well… over a wide range of frequencies, from 1 hz to 50 khz. So we knew then that the spider silk was sort of an ideal, perfect sound sensor.
Hopkin: That was eye-opening for the researchers…but is it ear-tickling for the spiders?
Miles: So we set out to try to figure out if the spiders were actually able to hear sound using their web. And this was a hard question to answer.
Hopkin: For one thing, they had to…