Black widows are one of the most well known spiders in the world. This is largely due to the potency of their venom.
What are black widow spiders?
The term black widow applies to some spider species of the genus Latrodectus. They got their name from the females of these species, who sometimes kill and eat their mates. The males are generally smaller and have significantly less potent venom, so they are helpless against these femme fatales.
Black widow spiders that have the telltale red hourglass on their undersides are identifiable by that one feature. If you see that on a spider, it is an adult female black widow, without question. However, not all black widows have these markings. Many of them are shiny and black, but males are typically not black. Males are grey or brown and may have white or yellow hourglasses.
Black widows have worldwide distribution, except for the continent of Antarctica. In the United States, there are northern, southern and western variants of these spiders.
Black widow behavior, diet and webs
Black widows are web-weaving spiders. They construct webs to catch prey. Like other web-weavers, they will wait for their prey, which is primarily insects, to get caught in their webs. At that time, they bite them, wrap them in silk and wait to dine on them.
Like most spiders, the eating habits of the black widow are quite gruesome. They inject what is essentially digestive juice into their victims so that their insides will become liquid. This is something like digestion, though it happens outside of the black widow. Once the insect is liquified on the inside, the black widow sucks out the liquid.
Black widows build what are known as cobwebs. Therefore, there are no intricately patterned webs like some other spider species create. They layer silk until they have a web strong enough to hold them, potential offspring and dinner. They usually do it in dark, isolated places, such as lawn piles, rotting logs, woodpiles, or under rocks and sheds. When they enter houses, they are most likely to live in a garage or basement.
The bite of the black widow
Black widow spiders are known because of the female's bite. It can produce severe discomfort and even occasionally death for humans. The latrotoxin injected by the females (and by males to a much lesser degree) is a neurotoxin that can produce nausea, vomiting, trembling, aches and difficulty breathing.
Despite their reputation as people-killers, black widows are not big on biting humans and their venom is rarely deadly, though people who are bitten can become very uncomfortable. Black widow spiders like to stay in their webs, wait for food and procreate. When one bites, it is usually because it feels threatened, typically through accidental human contact.
The life cycle of the black widow
Black widow spiders are about 1/2-inch long, not including their legs, which make them about 1.5 inches in diameter. They weigh roughly one gram (0.035 ounce). They are not particularly large as venomous spiders go, but they are notorious.
Black widows only live from one to three years in the wild. A female will lay about 100 to 300 eggs, and most of the offspring will not live. Those that do leave the nest after hatching, already fully independent.