These Spiders Use Their Webs Like Huge Silky Ears

Karen Hopkin is a scientist. My name is Karen Hopkin.

Some things are so cute that we think they are bugs ears. bugs don't have ears A new study shows that orb-weaving spiders can detect sound. The findings are published in the national academy of sciences

Any animal is likely to have an ear.

Ron Hoy is a researcher at Cornell University.

All the way from tiny crickets to flies that are even smaller than crickets.

There are a lot of animals that don't have eardrums. They still listen.

Ron Miles is that person.

There are two Rons here.

Ron Miles has been working with Ron Hoy for thirty years.

An hour's drive from Cornell.

Hopkin said that animals without ears receive audio input.

Spiders and insects have hairs on their bodies.

The air currents that comprise sound waves can be detected by the whispy little filaments.

Since we knew that so many animals like small insects and spiders have hairs that can sense sound, we were wondering how to make something that could sense sound like that.

During an afternoon stroll, there was a chance.

If you look at a spider web in the wind, it moves with the wind. He thought a spider web or spider silk could be a sound sensor.

The researchers tried to get a spider to give them some silk.

When we played sound at a small strand of spider silk, it moved with the air in a sound field over a wide range of frequencies... The spider silk was a great sound sensor.

Is it ear-tickling for the spider?

We wanted to see if the spiders could hear sound using their web. This was not easy to answer.

They had to find a way to get the entire web into the soundproof chamber.

Spiderwebs are very delicate. It is not possible to find a spider web in the woods and take it to your house. Things are attached to it. It's difficult to get it intact.

The spider in Charlotte's Web is made by the orb-weavers.

Hoy: We are talking about a really great web. If you walk through any of the fields in upstate New York, you will either see or avoid the wheel-shaped web. It can be as large as a meter.

The two students came up with a way to make custom-made webs.

They made a small wooden frame and put it on the windows of our building.

Hopkin said the lights in the building attracted bugs.

The frames were used by the spiders to build their webs. My students would hijack the spiders in the morning and put the frame in the chamber intact.

How can you tell if a web works as a hearing aid for arachnids? It is possible to keep an eye on the spider.

The recordings from the nervous system sensory system were made by my lab and they showed that you get an acoustic response from the nerves to sound.

The spider's actions were more revealing.

You could get a strong response from the spider if it was loud. It's hunkering down. It's indicative of an alarm response.

When it's serenaded with sounds that are 10 decibels or 100 times softer...

Without changing its body posture or making any other movements, it could raise its front two legs off the web.

Hoy says that leg lift.

It is a spider's way of seeing what is coming. We don't know what that means. The spider might just be reacting to the fact that they need more information. The demonstration was needed to showspiders can hear sound

This approach to acoustics could change the way microphones are made and the way they are used.

Karen Hopkin is for Scientific American's 60 second science.

This is a transcript of the show.