Red-back spiders do NOT always have a “red” marking. Males are black and can be quite small. The larger, venomous female is black and has the characteristic red stripe on top of her abdomen. It’s her warning sign.
Female adults get to about 10mm; males much smaller at 3-4mm.
Female is highly venomous; males don’t bite.
Yes, but a messy web, down low or tucked in warm, sheltered locations.
Commonly found in and around people’s houses; makes home in dry, dark places like rubbish piles, letter boxes, under disused furniture, door or window frames, under the lip of bin lids or wooden steps and yes, even toilet seats.
As the female rarely leaves her web, humans are not likely to be bitten unless some part of the body (e.g. the hand) is put into the web.
Redbacks have caused human deaths, but not since anti-venoms were made available in 1981. Only a small amount of venom is required to make a person seriously ill as it attacks the nervous system. If you are bitten, you will notice a sharp, pin-prickling sensation commences within five minutes around the site, slowly becoming hot and increasingly painful, often with localised sweating. Reactions can also involve headaches, nausea, vomiting, abdominal pain, fever, hypertension and in severe cases, paralysis. Pain around the bite area can be excruciating, so if bitten or even suspected, seek medical attention as immediately as possible.