From MSNBC:
Spider silk could stop a Boeing 747 in flight, is stronger than bullet-proof Kevlar and more elastic than nylon, biologists say. “All spiders spin at least one kind of silk and some spiders can produce seven different types,” said Cheryl Hayashi, a University of California-Riverside biologist.
Most spider silks vary in their strength and elasticity. “Dragline silk is the strongest silk because it supports the weight of the spider,” said Hayashi’s colleague Randy Lewis at the University of Wyoming. This silk attaches the arachnid to the web and provides support like a rapeller’s rope as the spider drops below the web to avoid prey.
Most people thinking of spider silk envision an insect-catching orb web, a wagon-wheel shaped net with its spokes made from strong silk. The center of the wheel, the capture spiral, is made from flagelliform silk that is covered with sticky adhesive droplets. Once dinner is caught, spiders use achniform silk to wrap and immobilize their prey, Hayashi said.
“Spiders are incredibly fascinating in the way they make and are able to manipulate their silks,” she said. “They can even recycle their silk by eating it — it’s a good source of protein.”
More here.