Black widow hanging out on my planter
I don't like spiders. I know, deep down, that they are unlikely to hurt me, and that they eat flies and other pesty insects. Even so, I have a visceral reaction when a spider crawls into my vicinity. I'm pretty much OK with spiders that stay outside (although stumbling on a big one, like the one Zuska found on her rain barrel might cause me pause1).
But black widow spiders (Latrodectus hesperus) are another story. They are indeed venomous and their bite is supposed to be quite painful. Just reading about the symptoms makes me cringe:
Severe muscle pain and cramps may develop in the first two hours. Severe cramps are usually first felt in the back, shoulders, abdomen and thighs. Other symptoms include weakness, sweating, headache, anxiety, itching, nausea, vomiting, difficult breathing and increased blood pressure.
But no one in the U.S. has died from a black widow bite in over a decade, so it's not that bad, right?
Fortunately, black widows rarely end up inside the house. Instead they make their webs in dark nooks and crannies, usually only coming out after dark or if they are disturbed. Their amorphous webs - straight from a haunted house - are pretty easy to spot and sweep away. They leave me alone and I pretty much leave them alone.
Brown is apparently the "New Black"
But then one of the local newspapers had to run an article ensured to freak me out a bit: "Brown Widows Now in Inland Area"
Brown widows (Latrodectus geometricus) are cousins to the black widow. They are more drably colored than the black widow, with brown bodies and an orange or yellow hourglass on the abdomen. Brown widows are originally from South Africa, and have been working their way west from Florida for the past 10 years or so. Only recently have they appeared in Inland Southern California.
How do brown widow spiders compare to black widows? According to the article:
- Brown widows are more abundant than black widows. According to Rick Vetter, who studies spiders at UC Riverside, "Where you might find six or seven black widows in a backyard, now you find 100 brown widows."
- Brown widow venom is twice as toxic as black widow venom.
- Brown widows live in more open locations - such as under patio chairs and in chain link fences - than black widows
They sound pretty nasty, right? I'll admit I went out to my patio and made sure there weren't any webs on my plastic patio chairs shortly after reading the article.
But the real story - easy to overlook among all the scary-sounding description2 - is that brown widows are much less likely to bite than black widows, and when they do, they don't inject as much venom. That means that they aren't actually considered to be dangerous.
As the UCR Spider Research site explains:
A South African medical journal reports on the bites of 15 brown widows in humans (Muller 1993) . Only two symptoms of brown widow envenomation were reported in the majority of bite victims: 1) pain while being bitten and 2) a mark where the bite occurred. That's it. Not much more. The bite of the brown widow is about the same as any non-poisonous spider. It hurts and leaves a little mark on the skin. It is no big deal. There are none of the serious, protracted symptoms that one would exhibit when bitten by a black widow.
So the appearance of the brown widow really is good news, at least from the public safety perspective, because they may be displacing the black widow, which is dangerous.
I'll still be happier if I never run in to one.
If you want to help track the spread of the brown widow spider in California, you can mail any brown widows you find outside of San Diego, Orange, or Los Angeles County to Rick Vetter at UC Riverside.
If you are in Los Angeles County, you can also participate in the Los Angeles Spider Survey, sponsored by the Natural History Museum of Los Angeles.
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1. Where "pause" means that I get my husband to move it away from any outdoor equipment I want to use.
2. Especially when the article concludes with advice from an entomologist with the National Pest Management Association who advises (not surprisingly) dusting with pesticides or calling an exterminator. "Kill them all" seems a bit over-the-top advice for non-dangerous spiders.
Top image: By me.
Bottom image: thumbnail of graphic from the Press-Enterprise article "Brown Widows Now in Inland Area". Click the thumbnail to see the full-sized image.
Good article. The only thing I would add is that the black widows bite is actually fairly mild at the time it happens. Some people don't even know they've been bitten. But they sure know it later! http://www.pestcontrolcenter.com/blog
be careful out there
[...] yesterday’s post about black and brown widows made you want to learn more about venomous spiders, you should check out DN Lee’s latest post [...]
The one point you are overlooking here is the bigger concern that this is yet another exotic species that is displacing native ones. No one knows how much damage it could do to beneficial organisms and our ecology in general.
[Edited to remove irrelevant link. You are free to link your name to your web site.]
Probably the reason for this UCR Spider Research is that because brown widow spiders are smaller than the black ones to penetrate the human skin and inject enough venom. But if we're going to look at the actual danger that these brown widows can cause, they're more dangerous than black. Source: brownwidowspider.net