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Black widow spiders are known for their potent venom, which is up to 15 times stronger than a rattlesnake's, but bites are rarely fatal to humans. These spiders prefer dark, dry places like wood piles, barns and basements, and are generally not aggressive unless disturbed. Female black widows are distinguished by their shiny black bodies and red hourglass markings, and they are more likely to bite than males. David Nelsen, an associate professor of biology at Southern Adventist University in Collegedale, Tennessee remembers sprawling on his belly under the slide at the elementary school playground, in search of the tangled web of the Latrodectus hesperus, aka the western black widow spider. He'd know it when he saw it, the sticky silk threads spun in messy snarls characteristic of such wondrous creatures. If he nudged the web with his long forceps in just the right place, he could catch the spider before it escaped and tuck it into one of his plastic bags where dozens of other black widows lay in wait.
It didn't matter that one bite from the shiny black spider could send his muscles into painful spasms within minutes; That even if he went to the emergency room writhing in pain, doctors likely wouldn't have the antivenom to treat him; That he'd have to wait out the burning, throbbing, and involuntary muscle contractions for hours or possibly days until his symptoms eventually subsided. They played a starring role in his doctoral research, and he wanted to understand them better. So how did the black widow spider get its name, and why do people find them so scary? Nelsen chose the black widow for his research because "they're mysterious and dangerous," he says. Indeed, the black widow is one of the deadliest spiders in the world, according to Encyclopedia Britannica. About 2,600 black widow bites are reported to the U.S. National Poison Data System each year. But its name comes not so much from the spider's ability to kill humans, but from a cannibalistic behavior noticed in the species during copulation.
An entomologist collected samples of male and female black widows and stored them in the same container. When he came back to check on the spiders, he discovered that the female widows had eaten the males. This so-called "spider cannibalism" is not that rare in the spider world in general, Nelsen says. It usually involves the female eating the male before, during or after copulation. But it is rarely seen in black widows that inhabit North America. Black widow males, in nature, tend to escape quickly after copulating - a luxury they weren't afforded caged together with females in a laboratory setting. Also, research shows that male black widows can sense chemicals in the female's web that indicate whether the she has recently eaten. They know to avoid hungry females, just in case. They hide during the day in tiny crevasses or rodent holes, and creep out onto their webs during the night. When they do, they usually hang upside down waiting for a fly or grasshopper to get trapped in the sticky threads of their web.
When an insect gets caught, the widow quickly runs over and wraps it in silk. At mealtime, the spider digs its fangs into its prey, injecting the insect with digestive juices until it liquifies, and then the widow sucks up the resulting bug juice. Female black widow spiders are about 1.5 inches (3.8 centimeters) in length, with long legs. Males are about half that size. Female black widow spiders have a shiny black body, with the well-known hourglass shape on their abdomens, in red, red-orange or yellow. Males are lighter in color with red or pink spots. But color variations and markings vary depending on the species. Black widow spiders are generally not aggressive. In fact, they will only bite a person if they're touched, trapped or sat upon. There are 32 species of spiders in the Latrodectus genus, many of which are considered true widows. You can find black widows in every continent of the world except Antarctica.
The western black widow (Latrodectus hesperus), southern black widow (Latrodectus mactans), and the northern black widow (Latrodectus variolus) are found mainly in the southern and western regions of the United States. They're shy, even. If you find one, there's no point in grabbing bug spray or swatting it dead. They won't come after you. In fact, they don't want to be around you as much as you don't want to be around them. Leave them be. Black widows play an important role in our ecosystem, feasting on many insect species, especially small, annoying insects like mosquitoes and flies. Bites usually occur by accident, for instance, when you stick your hand in a gardening glove and startle one hiding there. Females are much more likely than males to envenomate (inject venom into) humans. The venom is pretty potent - up to 15 times stronger than a rattlesnake's, according to National Geographic.
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