JoAnne Skelly: Black widow spiders

I’m fairly tolerant of most insects and spiders. I try to move them outside if I find them in the house rather than kill them. However, I do kill black widow spiders. It seems as if this was a banner year for black widows. I never used to find them in the house, only in the detached garage. Lately, I have found quite a few indoors.

These shiny black female spiders with the colored (yellowish to red) hourglass mark on their abdomens usually only have a venomous bite when their lives are in danger. Then, they are said to have venom 15 times more potent than rattlesnake venom. Pain in the arms, legs, chest, back and abdomen can be felt within minutes of a bite.

Otherwise, a black widow bite is usually non-venomous. According to the American Association of Poison Control Symptoms Centers, there were 1,866 black widow bites in 2013, but only 14 bites resulted in severe symptoms and there were no deaths. I’m not interested in finding out how my body reacts if I’m bitten, whether I have extreme muscle aches or cramping, difficulty breathing, nausea or vomiting or whether I’m one of those who have no serious damage. Bites can be fatal in some instances to small children, the elderly, people allergic to the venom or the infirm. I suspect pets would suffer if they were bitten or if they ate a female black widow.

I do feel badly about killing this excellent insect predator. It isn’t aggressive; it’s actually quite shy. It bites only in self-defense or when disturbed, for example if you stick your hand on one while you are grabbing a piece of firewood and disturb its nest. Supposedly, it only bites when pinched along the length of its body. A simple poke generally sends it scurrying away.

If you see a really messy web mass — beware — that’s probably a widow’s web. Avoid woodpiles, rubble piles, under stones, rodent burrows, sheds and garages. They live inside in undisturbed cluttered areas such as basements and crawl spaces.

If you receive a bite, clean the bite area with soap and water. Apply ice to slow the absorption of venom, elevate and immobilize the extremity. Even if most bites are not severe, to be on the safe side, seek immediate emergency medical attention, especially if you have a heart condition. Pain and symptoms generally go away in two to five days.

JoAnne Skelly is Associate Professor & Extension Educator, Emerita at University of Nevada Cooperative Extension. She can be reached at


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