Spiders are not insects. They belong to the Arachnid family. There are more than 30,000 species of spiders.
They have two main body parts: The cephalothorax, which is a fused head and thorax, and an abdomen. They have eight legs and up to eight eyes, but they have very poor eyesight and some are actually blind. A spider has no backbone but it has an exoskeleton made of a tough material called cuticle.
Spiders have no wings or antennae.
They have tiny, sensitive hairs and claws on each leg. The hairs help them feel when an insect has been caught in the web, and the claws can help them cut the web when necessary.
A spider is born knowing how to make a web. At the tip of its abdomen on the underside, there are three pairs of glandular tubes called spinnerets, although some spiders may have more or less. The spinnerets produce liquid silk, which hardens as soon as it comes into contact with the air.
The spider can make different types of silken thread by using different spinnerets : Dry or sticky, thin or thick, smooth or rough.
Sticky silk is used for trapping prey, the non-sticky silk makes pathways for the spider to walk on, and a third type is used to make a cocoon to hold the mother's eggs.
The first piece of silk from a spinneret will attach itself to an object which serves as an anchor. The spider will then strengthen and enlarge the web following an intricate pattern it knows by instinct.
The webs may look delicate and flimsy, but they are strong, flexible and able to take a great deal of stress. The threads in a spider web are five times stronger than an equal amount of steel.
Still, the webs are not long-lasting. They may be damaged by captive insects, severe weather, or some will just dry out in a day or two. When these events occur, the spider wastes nothing. It will roll up the old web and eat it, providing material for a new creation.
A spider can build a beautiful, intricate web in just an hour.
TYPES OF WEBS
Among the more common types are:
* Orb webs: They are shaped like a wheel. The threads which go from the center to the supports are called radial lines; those going around and around the web are known as orb lines.
* Sheet webs: Large, flat webs you might see draped over a bush, or a tree branch.
* Funnel webs: These are almost cone-shaped. The spider can hide inside and wait for its prey. When the bug gets stuck on the sticky threads, the spider comes out for lunch.
* Tube webs: May run along the ground or up tree trunks.
Spider webs are amazing creations. As one Ethiopian proverb observes: "When spider webs unite, they can tie up a lion."
Some spider webs are so strong that native peoples twist them together to make fishing nets. Others use the webs like Band Aids since they are thought to have antiseptic properties.