Redback Spider (Latrodectus hasselti): is a spider that is familiar to most Australians. It is thought to be the same species as the Kapito of New Zealand and the Black Widow of North America. The female has a body length of 1.4 centimetres while the male is much smaller with a 3-millimetre body. Redbacks have shiny pea-shaped black or dark brown bodies. There is a distinctive bright red or orange patch on the top and bottom of the abdomen. The female has a dangerous bite. The males are too small to cause any damage.
Weight for weight, the Redback is considered to be Australia’s most poisonous spider. An antivenin was developed in 1956. Although many people are bitten annually there have been no fatalities since 1956. Redbacks are usually timid and most bites are due to accidental contact.
Redbacks have an interesting history in Australia. They were not described, in this country, until 1870. They do not feature in Aboriginal legends, are abundant around human habitation and are rarely found in the bush. If they are native and were present at the time of European settlement then why did it take so long to find one? Redbacks were probably introduced and hitched a ride to Australia in cargo brought in by sailing ship form foreign shores.
A few years ago a couple of specimens were found in Japan. This caused a national panic akin to the arrival of an earthquake.
Over the past few years we have had a close and almost intimate relationship with Redbacks. Since using sheets of roofing iron, in the garden, (see organic herbicide) the number of Redbacks that we encounter has increased considerably. They set-up residence on the under surface of the iron in the corrugations. Although the iron becomes extremely hot in summer the spiders do not seem to mind the high temperatures. They are sluggish and very timid so the Redbacks pose no threat to our safety. The record for the number of spiders under one sheet of roofing iron stands at twelve.
Redback Spiders spin a rather rudimentary web but still manage to catch a wide range of insects. We have observed that beetles are very susceptible to entanglement by Redbacks.
Some of this information was gleaned from the Green Guide: Spiders of Australia by Terence Lindsay and published by New Holland Publishers.