Black widow spiders are notorious for their strong venom and horrible mating habits, where the females sometimes kill and eat the males after reproduction.
There are 31 species of these spiders, all belonging to the genus (group of species) Latrodectus, as data from the Integrated Taxonomic Information System (ITIS) show.
Black widows are found in temperate zones around the world, including parts of the United States, Europe, Asia, South America, Australia and Africa.
They lead a solitary life until the mating season comes and it is time to mate with a member of the opposite sex.
The spiders are named after the preference of the females to kill their males after mating. The females often eat the males after killing them, although scientists speculate that this act provides them with a source of protein.
In the wild, black widows can live up to three years, although males tend to live a much shorter life due to this bizarre mating behavior.
Adult female black widows measure about half a centimeter in length and are usually more than twice as large as the males of their species, although they can sometimes be up to 20 times larger. This is according to a report entitled “Black Widow Spider Toxicity”, published this year by scientists at Brooklyn Hospital Center and St. Luke’s University Health Network.
Females are easily recognized by their shiny black bodies and the characteristic hourglass-shaped markings on the underside of their abdomen, which can range from yellow-orange to red, according to the Occupational Safety and Health Administration (OSHA) of the U.S. Department of Labor.
Men may be gray or black in color and may have red or pink patches on the top of the abdomen.
Only female spiders pose a risk to humans, with a venom that is believed to be about 15 times more potent than that of a rattlesnake. In fact, black widows are considered the most poisonous spiders in North America.
However, despite widespread belief, bites from Black Widows are rarely fatal. In the United States, approximately 2,600 bites of Black Widows on humans are reported each year, with only 1.4 percent of these cases showing severe symptoms, according to data from the Black Widow Spider Toxicity Report.
Although rarely fatal, a bite from these spiders can still be a painful experience. The venom can cause severe muscle pain, nausea, excessive sweating, high blood pressure, fever and mild paralysis of the diaphragm, which can make breathing difficult.
The pain caused by the bite can last between eight and 12 hours, while some symptoms can last for several days – although most people make a full recovery.
The people most at risk from a black widow’s bite are young children, the elderly or people who are very ill. The spiders are not aggressive and only bite when they feel threatened, e.g. when someone accidentally sits on them.
Black widows eat a variety of insects, which they catch with their webs. Once an animal is caught in the web, the spiders cover it with silk and inject it with digestive enzymes that liquefy its body. This allows the black widow to easily absorb the resulting juices, National Geographic reported.
According to OSHA, black widows are commonly found outdoors in wood piles, rubble heaps, under rocks, in hollow stumps, rodent dens, sheds and garages; and indoors in attics, basements and behind the backs of furniture.