Redback spiders, Latrodectus hasselti, are poisonous spiders found throughout Australia. They are in the family Theridiidae, which is found worldwide, and they are closely related to the black widow spider. Female spiders may live for up to three years (they mature at about four months old) but males only live for around six months (maturing at three months).
Most redback spiders can be fairly easily identified by the red stripe or 'hourglass' on their back. However, different types of redback spiders look different. Female spiders have a pea-shaped/sized black or occasionally brownish body with a red stripe on the back and a red or orange spot underneath (as this is on the underside of the abdomen it is usually difficult to see). Male spiders are much smaller than the females and generally have a brown-coloured body with a red or orange stripe on it, and white markings. Juvenile spiders can often be recognised by the extra white markings found on their abdomen.
Redback spiders prefer to make their webs in sheltered, dry sites – this is why they are often found in or near areas where people live. They like to hide among rocks or logs, or inside sheds, woodpiles1, garages and even sometimes toilets! Many Australians love to taunt tourists by warning them to look under the toilet seat for redbacks before they sit down – some people have been bitten by spiders in toilets! Redback spiderwebs are usually above-ground and in a slight funnel shape, with threads leading down to the ground. As most spiders do, redbacks generally feed on small insects and have been known to kill other larger animals that become entangled in their webs, including other spiders. Sometimes they steal food from webs made by other types of spiders. The daddy-long-legs spider eats redback spiders, and white-tailed spiders have also been known to kill redbacks.
Female redbacks make the webs, and males often hang around the edges when they are ready to mate (in summer). Males usually end up being digested and do not survive mating - from a single session, females can store sperm that will last them a couple of years and enable them to lay several batches2 of white egg sacs.
Redback spider bites are toxic and can even kill. However, with anti-venoms available nowadays death is rare (assuming you are aware of the bite and are able to take quick action after the bite). Redbacks do not usually bite unless provoked, therefore it is not recommended that you stick your hand into their nest. Even if you should be bitten, the spider's jaws are not strong enough to ensure that each bite severs the skin and releases venom. Redback spider-bites begin by causing severe pain, sweating, nausea and vomiting and even muscular weakness. Many people whose bites went untreated have claimed that some of these effects continued for months.
The best thing to do after a redback bite is: try to kill3 or preferably capture the spider so it can be positively identified; apply an icepack (to reduce pain) but not a pressure bandage; seek medical attention, preferably by calling an ambulance.