Red back spiders (Lactrodectus hasselti) are closely related to the black widow spider, in North America. Redbacks, just as their North American cousins, possess potent neurotoxic venom. The Australian museum estimates that there are six hundred yearly bites that cause symptomatic episodes. Although, deaths have been recorded with the bite of the redback, none have occurred recently due to the availability of an antidote. Redback spiders range from Australia to New Zealand, New Caledonia, India through Indonesia and the Philippines. It, along with thefunnel web spider, are considered to be among Australia’s most venomous spiders.
Morphology and habitat
Redback spiders are relatively small spiders. The females can be one centimeter long with slender legs. Like the black widow spider, they have a red hourglass shape on their abdomen. In addition they possess a red or orange stripe on their upper abdomen. Males are much smaller and have less distinctive markings.
Redbacks will live anywhere that provides warmth for breeding, adequate food and a secure shelter. They too like undisturbed areas, yet prefer being close to populated areas. They make dense, strong funnel-like webs and feast mainly on insects. They have also been known to consume other spiders, crickets and small lizards.
Mating
A common misconception is that female widow spiders consume the male after mating. This is usually not true. Most males that are eaten are mistaken as prey. The male redback, on the other hand, usually will not survive the mating process. During mating the male, to occupy the female’s attention, will offer himself up during the mating process. As the sperm is being place in by the male’s palps, he places his abdomen by her mouth. She, during this process, will start secreting digestive enzymes into his abdomen. If not too weak, he will withdraw and return for a second mating. During this time, the female continues to digest the male abdomen. Needless to say, the male usually dies at this point. This behavior seems specific to the redback widow spider. The female, can preserve the sperm for up to two years if needed, and can produce numerous egg sacs containing several hundred spiders each. The sacs are secured to the web and the spiderlings emerge within a few weeks.
Bites
The redback spider generally doesn’t leave or wander away from the web. Most bites occur when the victim inadvertently places their hand onto the web. The fangs of the female have the potential to penetrate human skin, and when it does can cause toxic neurological reactions. Due to the small fang length, many bites aren’t sufficiently deep to cause problems. The males are even smaller, and generally are much less dangerous. If bitten, prompt first aid and a trip to the doctor is advised. A cold pack should be placed on the bite area and the spider should be collected for identification. Due to the availability of antivenom, no new recorded deaths have occurred.
Redback spiders are dangerous creatures. If in an area inhabited by them, use precautions. Remove clutter, use insecticides if needed and wear long sleeves shirts during cleanup near debris piles. If bitten, seek medical attention promptly to prevent complications.
References
Simon-Brunet, S. 1994. The Silken Web: a natural history of Australian Spiders. Reed Books
Pyers, G. 1999. Australian Animals: Spiders. Heinemann Library
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