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Most of us think that spiders use silk
only to spin a web.
Actually, no other animal uses silk in as
many ways as spiders do. They make it into houses, life lines,
diving bells, cocoons, "aero planes", lassos, spring traps and
the web we all know.
Spiders are not insects, but belong to a
species called "arachnid" . Unlike insects, they have eight
legs, eight eyes in most cases, no wings, and only two parts to
their bodies.
Spiders are found in practically every
kind of climate. They can run on the ground, climb plants, run
on water, and even live in water.
The spider manufactures its silk in
certain glands found in the abdomen, or belly. At the tip of the
abdomen there are spinning organs which contain many tiny holes.
The silk is forced through these tiny holes. When the silk comes
out it is a liquid. As soon as it comes into contact with the
air, it becomes solid.
The spider makes many different kinds of
silk. It makes a sticky kind that is used for the web, because
this catches insects. For the spokes of the web it makes a
stronger silk, which is not sticky. And it makes a still
different kind of silk for the cocoon.
Even the webs that spiders spin are of
many different kinds.
The wheel-like web is the one we see most
often. There are also "sheet" webs, which are flat and shaped
like funnels or domes. And the trap-door spiders make a burrow
out of their web with a lid like opening at the top to catch and
hold their prey. Other spiders build a bell-shaped home of silk
which is entirely under water! |
