Spiders

Spiders were among the earliest animals to live on land - 380 million years ago, more than 150 million years before the dinosaurs.  They live in almost every habitat on earth. The only places where there are no spiders are the Polar Regions, the highest mountains and the oceans. As of 2008, at least 43,678 species of spiders have been identified worldwide.

It is estimated that 10,000 species of spiders are found in Australia.  Only a few species, including the Redback Spider and some funnel-web and mouse spider species, can inflict bites that are potentially fatal to humans. Most spiders only bite humans in self-defense. Antivenom for two of our more dangerous spiders, the funnel-web and the redback has been available since the 1950s and 1981, respectively.

Two important facts. Even though spiders tend to incite fear and even provoke phobias for some:

1.   Spider venom contains a cocktail of chemicals, primarily designed for small prey, not humans

2.   Spiders are less life threatening than snakes, sharks, bees and car crashes

Spiders are an important and fascinating part of our natural environment. Their webs are wonders of natural architecture.  They have major ecological and agricultural roles as killers of insects. Both their venom and silk are being used in medical research (stroke treatment), pest control (insect specific pesticides) and fibre technology (transgenic biosilk production) from the silk produced from their glands in their abdomen.

Interestingly, spider silk provides a combination of lightness, strength and elasticity that is superior to that of synthetic materials, and spider silk genes have been inserted into mammals and plants to see if these can be used as silk factories.

Some of the smallest spiders in the world are never seen by most humans because they only have pinhead-sized bodies. Small spiders are usually found in damp, cool habitats like forest leaf litter and moss because their small bodies can lose water rapidly in dryer conditions. The largest spiders in the world include the South American Goliath Tarantula, some so big their legs can span a dinner plate. Such spiders may take decades to reach such a size. However, spider size is limited, partly because their respiratory physiology becomes less efficient at very large sizes. Although most spiders live for at most two years, tarantulas and other mygalomorph spiders can live up to 25 years in captivity.

Natural spider management can include:

§  Sealing cracks, holes and openings in structures

§  Inspect plants, firewood, containers and other goods before bringing them inside

§  Vacuuming spiders and their webs from the interior and exterior of structures

§  Keep stored goods like bins, ladders and shelters well away from structure exteriors.

§  Use non insect attracting lights.

§  Vegetation and leaf litter well away from structure exteriors.