Sherry Bee, age 12, of Vancouver, B.C., for the question:
What material does a spider use to make her web?
The gossamer threads of a spider web are made of fine strong silk. If we could gather enough of it, we could weave it into delicate cloth. But this we cannot do for a very good reason. Spiders are fierce, bloodthirsty little creatures to whom canniballsm is not a crime. When several spiders are kept in one box, they are quite likely to dine on each other, A hundred silkworms can share a box and dine happily on mulberry leaves. Later, the threads are gathered from their silken cocoons. To gather spider silk, we would have to provide a separate home for each little spinner. What's more, spiders live on meat and the whole project would be uneconomical.
Nevertheless, a small amount of spider silk is gathered and put to good use. It is used to make the fine cross lines in certain microscopes telescopes and gun sights. This silk is elastic and strong enough to bear the weight of a fat spider, She uses it as a tight rope' a bridge aril as a rope on which she dangles in the air. Woven in a web, the silk of course, becomes a snare strong enough to hold a struggling fly,
The silk material is made inside the spider's abdomen. It is manufactured by special glands and while it is inside the spider's tummy it is in liquid form. This supply of liquid silk is connected to a number of fine tubes. At the tail end of the spider's body are her spinnerets, little buttons which act as faucets to let out the liquid silk. Each spinneret is fed by a large number of tubes from the liquid silk which is constantly being made by the silk glands.
When the spider starts to spin, she first pushes her spinnerets against some solid object. This forces out a little of the liquid silk which hardens into a gossamer thread on contact with the air.
The spider then walks away from the thread, paying out the line with one of her back feet as she goes.
Sometimes she climbs up high and waits for the thread to stick to a twig. Then the little spinner takes a flying leap. She may go straight down or she may wait for the breeze to blow her to a twig across the way. In any case, as she falls she pulls out her thread from her spinnerets. Sometimes the wind may blow hard enough to force the silk from her spinnerets. But the spider can never squirt out the liquid silk. It must be pulled out as she walks away or takes a flying leap or is pressed out by the wind.
As a rule, the spider has six spinnerets. But the silken thread comes in different qualities depending upon where it is needed. The spider can press all six spinnerets together to make a tough cable of silk or she can separate them to make a broad ribbon of silk. For the cross supports of her orb web she may use several threads of her strongest cable, The spiral threads of the orb web are of finer silk. She also uses the fine silk to line her nest and to make the cocoon which cradles her eggs,