[Chris Blakey]

Chris Blakey asked the Naked Scientists:

I was wondering what cobwebs are made of. I know they have something to do with household dust, but I'm not sure how or why dust particles would form into ropey strands. How does it work?

Thanks so much,
Chris

Cabot, Arkansas, USA

What do you think?

[blakestyger]

Household dust?
Web silk is a protein substance of very high tensile strength. There are different silk glands in the spider's abdomen that produce silk for separate purposes - egg wrapping, prey disablement or web making. Interestingly, spiders cut their webs using digestive juices rather than physically separating it with mouthparts.

[JimBob]

The web silk spiders produce is sticky - the cobwebs you see are the result of spiders abandoning these webs for better pickings somewhere else. The spooky-looking things are the result, as you suggest, of household dust attaching itself to the web after the spider has abandoned the web. There are spiders that build a new web each night to catch prey.