It is known that in Australia lives more of the deadly snakes, spiders and other animals, such us crocodiles, White Sharks, The Inland Taipna snake, or the Blue-ringed Octopus.

Today we are going to focus in The Redback Spider.

The Redback Spider (Latrodectus hasseltii) is a species of venomous spider indigenous to Australia. It is a member of the cosmopolitan genus Latrodectus, the Widow Spiders.
The adult female is easily recognised by her spherical black body with a prominent red stripe on the upper side of her abdomen and an hourglass-shaped red/orange streak on the underside. Mainly nocturnal, the female redback lives in an untidy web in a warm sheltered location, commonly near or inside human residences where they can find an adequate food supply and warm places. Redback Spiders are less common in winter months.

The redback is one of the few spider species that can be seriously harmful to humans, and its preferred habitat has led it to being responsible for the large majority of serious spider bites in Australia. Predominantly neurotoxic to vertebrates, the venom gives rise to the syndrome of latrodectism in humans; this starts with pain around the bite site, which typically becomes severe and progresses up the bitten limb and persists for over 24 hours. Sweating in localised patches of skin occasionally occurs and is highly indicative of latrodectism. Generalised symptoms of nausea, vomiting, headache, and agitation may also occur and indicate severe poisoning. An antivenom has been available since 1956, and there have been no deaths directly due to redback bites since its introduction.

It preys on insects, spiders and small vertebrates that become ensnared in its web. It kills its prey by injecting a complex venom through its two fangs when it bites, before wrapping them in silk and sucking out the liquefied insides. Male spiders and spiderlings often live on the periphery of the female spiders’ web and steal leftovers. Other species of spider and parasitoid wasps prey on this species. The redback is one of few arachnids which usually display sexual cannibalism while mating. The sperm is then stored in the spermathecae, organs of the female reproductive tract, and can be used up to two years later to fertilise several clutches of eggs. Each clutch averages 250 eggs and is housed in a round white silken egg sac.

Distribution and Habitat

The redback spider is probably native to Australia; however, it has been suggested that it may have been spread to Australia by human activities The species was known by 1850 in South Australia, only 14 years after European settlement there, but had not been reported in early spider collections in other colonies.

The redback spider is probably native to Australia; however, it has been suggested that it may have been spread to Australia by human activities The species was known by 1850 in South Australia, only 14 years after European settlement there, but had not been reported in early spider collections in other colonies.
The redback spider is commonly found in close proximity to hum

an residences. Webs are usually built in dry, dark, sheltered sites, such as among rocks, in logs, tree hollows, shrubs, old tyres, sheds, outhouses, empty tins and boxes, children’s toys or under rubbish or litter. Letterboxes and the undersurface of toilet seats are common sites.

redback spider map

A distribution map of the records of redback spider specimens reported to the Atlas of Living Australia

Danger to humans and first aid

Redback bites occur frequently, particularly over the summer months. More than 250 cases receive antivenom each year, with several milder envenomations probably going unreported. Only the female bite is dangerous. They can cause serious illness and have caused deaths. However, since Redback Spiders rarely leave their webs, humans are not likely to be bitten unless a body part such as a hand is put directly into the web, and because of their small jaws many bites are ineffective. The venom acts directly on the nerves, resulting in release and subsequent depletion of neurotransmitters.

Common early symptoms are pain (which can become severe), sweating (always including local sweating at bite site), muscular weakness, nausea and vomiting. Antivenom is available. No deaths have occurred since its introduction.

Apply an ice pack to the bitten area to relieve pain. Do not apply a pressure bandage (venom movement is slow and pressure worsens pain). Collect the spider for positive identification. Seek medical attention.