Lifestyle and Lifespan
Black Widow spiders are known for their potent venom, which is 15 times as potent as rattlesnake venom.
As part of the family of comb-footed spiders, they have 6-10 comb-like bristles on the hind tarsi. They use their combs to fling silk strands over any captive that gets caught in the web. The swathed victim is hauled to a rest site on the web, injected with venom and later eaten.
Most common in the South of America. Found among fallen branches, under stones, in outbuildings and under objects such as furniture.
Black Widows primarily eat insects. However they will also eat diplopods, wood lice, chilopods, and other arachnids.
Black Widow Spiders help to control insect populations.
During the day, the female spider hangs upside down in her web, displaying her red hourglass marking as a warning to potential predators. If prey gets caught in her web, she will wrap it in silk, bite it, and drag it to a retreat inside of her nest to consume it. When eating, she will use her cheliceral teeth to mash up her prey. Then she pours digestive enzymes onto it, and sucks up the resulting food. This whole digestion process takes place outside of the spider's body.
When disturbed, black widow spiders will fall out of their web and play dead to avoid predation.
Black Widow Spiders only exhibit social behavior when searching for mates.
During the mating season, a mature male spins a small 'sperm web', or web in which he deposits a small amount of semen. He then covers his pedipalps in sperm, abandons his home, and travels in search for females. Once he finds a female, courtship begins. The male begins by vibrating the threads of the female's web, alerting her to his presence. If she is receptive, mating will take place when the male inserts his papal organs into the spermathecal openings of the female. His sperm is released onto her eggs, which are then laid onto a small web and covered with more silk until they are completely surrounded by a cocoon. This cocoon is then guarded or carried by the female until the eggs hatch and spiderlings emerge. A female black widow spider can store the sperm from one mate and use it throughout her lifetime.
One egg sac can contain anywhere from 20-900 eggs. While the female spider cares for the egg sac during gestation, parents provide no parental care once the eggs have hatched.
The common name, Black Widow Spider, originates from the females' behavior to sometimes eat the male spider after mating.
Their only known predator is the mud-dauber wasp.
McCorkle, Matthew. "Latrodectus mactans." Animal Diversity Web. N.p., n.d. Web. 17 Apr. 2017.
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Preston-Mafham, Rod. 1991. The Book of Spiders. Chartwell Books, Edison, NJ.