Roger Thomas, The Ballarat Courier's Nature Notes columnist, has covered an extraordinary range of flora and fauna in his writings over the years. In this occasional online series, we dig through the archives of a different subject or creature. Here, we uncover Roger's writings on one of the more notorious but commonplace of Australia's arachnids, the red-backed spider.
WHEN DO THEY THRIVE MOST?
The red-backed spider is a summer-lover. Its insect prey is more abundant in summer and it is able to remain drier when conditions are drier.
WHEN DO THEY BREED?
Red-backed spiders seem to breed almost year-round, but autumn may be the peak time for production of their woolly, spherical, buff-coloured egg sacs. I noticed some of these in a shed last week [from archived article, 2013]. They were in the typical untidy web in a metal object close to the ground. A plump female spider guarded them.
WHERE DO THEY LIVE? (BEWARE THE SHED)
The red-backed spider is widespread across the country, particularly in drier regions.
Sheds are great places for red-backs. They like the dry conditions and the relative seclusion. Outdoor furniture and under the rims and bases of garbage bins and big plant pots are other places to be wary of them. They prefer being almost at ground level. In natural conditions they live under and among rocks and logs.
The male also has a shorter lifespan, often being either eaten by the female while mating or dying soon afterwards
- Roger Thomas
Most local redback sightings are made in dry, dark, non-natural situations such as around yards, heaps of rubbish, old tires, inside sheds, under outside furniture and in plant pots and other empty containers. The overhanging rim around the top of the common "wheelie bin" seems an ideal spot, but I have not heard of any redbacks being found there.
Most of its activity is nocturnal.
WHAT DO THEY LOOK LIKE?
The female spider (pictured) is black with a distinctive contrasting orange-red stripe along the back of her spherical abdomen. The male is paler and without the red back mark.
[The female] abdomen is about the size of a pea (up to about 10 millimetres), but the male is much smaller and his abdomen is elongated (3 - 4 millimetres) rather than spherical.
The male also has a shorter lifespan, often being either eaten by the female while mating or dying soon afterwards.
WHAT DO THEY EAT?
Their prey is mostly ground dwelling insects. These are often common in sheds too. In a previous article we mentioned a red-backed spider entangling a skink in its web and killing it. That was in Ballarat East.
Now we have a report, with photos as proof, of a female redback with a 70cm snake in its web. This was from New South Wales, not from the Ballarat district.
The fangs of the male are small - too small to be a serious worry to humans
HOW LIKELY ARE THEY TO ATTACK?
The redback is not an aggressive spider. She seldom moves far from her web. She usually bites only when provoked or accidentally touched.
The male may wander, but he is not regarded as dangerous. The fangs of the male are small - too small to be a serious worry to humans.
HOW DEADLY ARE THEY?
Antivenom is available for red-backed spider bites. Anyone bitten should visit a doctor. Deaths are rare, but the very painful bite can be dangerous, especially for children and the elderly.
