The black widow is one of the most feared of the more than 30,000 known species of spiders because its bite can have very painful local effects on human skin. There are five species of this spider that are common to the United States, but two are much more prevalent -- the southern black widow and the northern black widow. The name of the spider comes from the incorrect belief that the female kills the male after they mate; while this does occur in some cases, it does not happen every time.
The female black spider is about 1/2 inch long and 1 1/2 inches long if the legs are spread. Males are about half this size, with longer legs and smaller abdomens. The abdomen of both sexes is shiny and globular in shape. The northern black widow features a series of red dots on the abdomen with two crosswise bars, while the southern black widow features a red hourglass shape on the abdomen. Babies of the species start out whitish in color and gradually turn black as they mature.
In addition to most of the United States, black widows live in temperate climates around the world, usually between 45 degrees north and south latitude. These spiders tend to live in the shadows -- such as the underside of rocks, plants and ledges. During times of drought or cold weather, they may move into structures such as garages and sheds.
Insects are the primary prey of black widows. These can include a variety of insects, including larger species such as beetles. The black widow's web is more haphazard than other species of spiders, which usually spin a web more circular in nature. After prey is caught, the black widow punctures the body and sucks the liquid contents out. Mud-Dauber wasps are one of the best hunters of black widows.
Effects of Bites
The neurotoxic protein produced by the black widow is one of the most potent venoms in the animal kingdom. Victims usually feel an acute pain where the bite occurred, with the symptoms beginning within 30 minutes of the bite. The area around the bite frequently swells up, and muscle cramps and weakness often occur. The blood pressure and heart rate can elevate, as well. Elderly people and children tend to experience more adverse effects from black widow bites than those of middle age, and life-threatening conditions usually only appear in these most susceptible groups.