Q How is spider silk made?

— Marie Thompson, Madison, Wis.

A PJ Liesch, director of the University of Wisconsin-Madison's Insect Diagnostic Lab:

Spiders have silk-producing glands in their bodies, specifically in their abdomen.

In these glands, they have the chemical components already put together to produce silk, but it’s in a liquid form.

When spiders want to produce a strand of solid silk, they have to pull this strand of silk out of their bodies.

Some spiders have special combs on their legs to help pull out the silk. In other cases, they might attach it to a substrate or surface and start walking to pull it out.

If you’ve ever noticed a spider dangling from a ceiling, it uses the silk as kind of a safety line. If it were to fall off of a surface, the silk is already there to catch it.

All spiders have silk-producing glands, but there are about six or seven different types of silk and different glands responsible for each one. Not all spiders have all these different types of glands, but in general, all spiders produce silk.

Spider silk is a very thin, narrow fiber. It’s extremely strong and also very elastic.

It’s very resilient, and it can stretch in the wind or due to mechanical stresses. When engineers look at that, they see an ideal fiber that you could potentially weave together to make extremely strong fabrics that are also elastic and lightweight.

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Blue Sky Science is a collaboration of the Wisconsin State Journal and the Morgridge Institute for Research.