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Friend or Foe?: The truth about the black widow 

Black widow spiders are commonly feared and for a good reason because their venom can quickly put the average person into the hospital.

click to enlarge natural-world_black-widow-1.jpg

Of all the spiders that crawl, creep, fly and jump about in Central Oregon, black widows are the most feared. There are others that can kill you, some quicker than the black widow, like Australia's the funnel-web spider, but throughout the entire world, black widows (latrodectus mactans) get the most press, and they should.

It's the adult female black widows that cause all the problems for man and beast as they pack a very serious venom and are also scary lookin': Black, with a shiny, bulbous abdomen, long legs with (or without) the red hourglass.
Anyone who thinks he or she has been bitten by a black widow should stay calm and seek immediate medical care, especially children and old duffers, like me. Black widow venom is very powerful, but usually not fatal to humans if taken care of quickly. There is a variety of treatments available that will prevent the venom from causing permanent damage and a complete recovery usually takes only about five days.

The male black widow has (as far as I know) no venom, he's an innocuous arachnid that spends his time wandering about looking for a female of his kind, and when he finds her, he probably wishes he hadn't. Female black widows usually devour the male during or after mating, hence her name. (Keep that in mind, guys!)

Believe it or not, the tensile strength of a female black widow's silk is the strongest known substance in nature. It is also the most uniform in size, so much so that it was used for bombsight cross hairs in WWII bombers. And, a scientific spider guy (arachnologist) once stated that it would be possible to replace the steel cables on the Golden Gate Bridge with black widow silken cables the thickness of a pencil.

Black widows use their silk to build a tangled structure that both traps prey and acts like an early warning system; the slightest vibration brings the spider to investigate immediately. If you find yourself crawling around under your house and feel a strong tug and hear crackling, be on the alert because you just stumbled into a black widow's web. The web contains silica and tinkles like breaking glass when broken, and the silken blobs about the size of your fingernail hanging in the complex webbing are eggs sacks.

One of the best things about black widows, as far as human contact goes, is that they're rarely found wandering around the house like common house spiders, or in their webs outside the window like Charlotte. Black widows require dark places and they do not enjoy sunlight. In addition to dark places under your house, they can be found in and under old lumber piles, refuse dumps, badger holes, outhouses and dark places beneath rocks. A beetle, termite, earwig, mouse, cricket or any other pestiferous animal that blunders into a black widow's web is frequently captured and eventually eaten by the spider.

"Eating" is not accomplished in the way you or I may think of it. "Digested" is a better term. Spiders inject enzymes into their victims and then after assimilation is underway they suck out the goodies, usually leaving the exoskeleton behind. And, black widows will take on anything that gets tangled in their web. I've found the corpses of large beetles, mice and small frogs suspended in black widow spider's web under my house.

Years ago, an ambitious female black widow was the focus of a noteworthy adventure at OMSI's Hancock Field Station over near Fossil. One hot afternoon, I noticed a group of students cheering and jeering around an old timber frame. My curiosity got the best of me and when I looked over the children's shoulders I saw a female rufous hummingbird tangled in a black widow's web. (Hummingbirds use spider silk to bind their lichen-and-flower-fuzz nests. Perhaps this female hummer thought one kind of silk was as good as another. Little did she know... )

When the hummingbird beat its wings furiously in an effort to extract itself, the black widow retreated to a dark corner and the children cheered. When the hummer became exhausted and stopped struggling, the spider would advance, and the children jeered. Eventually, the frightened hummingbird managed to untangle itself and escape, the children cheering it on, the spider grumbling.
This reminds me of a Far Side cartoon in which Gary Larson has two female spiders setting up a web at the bottom of a children's slide. One spider is saying to the other: "If we can pull this off, we'll live like kings."

How do you keep black widows out of your home? One way is to make sure that all the gaps and cracks between basement (crawlspace) and above are plugged. Watching and listening for the telltale web of the spider is another. Once discovered, the spider can be captured in a container - along with her white, silken egg sacks - and moved to a more suitable location.

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