SPIDERS IN GENERAL
Spiders belong to the order Arachnida, along with scorpions, harvestmen, mites and a number of other less well known animals.
Spiders differ from insects in lacking wings, and in having two body sections, instead of three, and four pairs of legs, instead of three. Most spiders have eight eyes, although some have less. Although some adult spiders are only 0.5mm long, the giant theraphosid spiders of South America can have a leg spread of 28cm and weigh 120 grams.
Australia has a large and varied spider fauna, with many species yet to be identified and named. The spiders described here can be found in and around around houses in the ACT and eastern NSW. The accurate identification of spiders requires specialized knowledge and equipment and this booklet is meant only as a general guide.
All spiders have a pair of fangs or chelicerae near the mouth that in most families are connected to venom glands.
The fangs are used to inject venom and digestive juices into prey. The prey’s tissues are dissolved in this way and the resulting ‘soup’ is sucked into the spider’s tiny mouth.
The spider’s abdomen is mostly filled with a network of tubes in which food is stored and digested. The elasticity of the abdomen means that large amounts of food can be eaten and stored at a time, allowing spiders to withstand long periods of starvation.
Silk plays an important role in all aspects of a spider’s life and it is produced from special glands at the tip of the abdomen. While some spiders use silk mainly for protecting their eggs and for orientating, others also build elaborate snares and webs in which to capture prey. Only a few species of spiders are capable of delivering a bite which seriously effects humans. The vast majority are harmless and play a vital role in keeping insect numbers in check. If you take time to observe spiders in your house or garden you will discover them to be interesting and fascinating animals.