Just what Use are Spiders?
Spiders are extremely important to agriculture and horticulture. They are predators and their main prey are insects, many of which eat our crops and pester our livestock. In Britain alone, it has been estimated that spiders eat more than the weight of the human population in insects each year! As natural pest controllers they are second to none.
Spider silk is incredibly strong and light and has found and continues to find many uses. The webs of the tropical orb-web spider Nephila have been used to make fishing nets in Africa and the Solomon Islands. If you have ever walked into a Nephila web in an African forest you would realise just how strong it is. By looping a springy mangrove bough to form a hoop and then striking a Nephila web a simple fishing net can be made that is quite strong enough to catch a half kilo fish. The silken strands were used to make fishing lines in Australia. In the New Hebrides, nets of spider silk were made to carry tobacco, arrow points and the dried poison for the points. Rain hats were even made of webs by some New Guinean tribes.
Makers of optical measuring instruments used (and occasionally still use) cross-hairs made of the silken strands of Araneus diadematus, Argiope aurantia, Zygiella atrica and other spiders. Telescopic gun sites employed threads of the Black Widow, Latrodectus, for sighting.
Spider silk has even been spun into fabric, but this was found not to be economic as the quantity of spider cocoons that were needed to make the silk was excessive. An alternative method of obtaining the silk involved 'milking' Nephila by hand and even semi-automatically, but this again was abandoned for practical reasons. However the silk produced was shown to be ideal for many applications.
Spider silk can now be made by inserting the gene for its production into animal cells. When inserted in goats for example, the silk could be extracted from the goat's milk. This technology is continuing to be developed and once perfected it only remains to be seen what other uses this incredible substance can be put to.