May 16, 2007

Creepy Crawler Carnival #3: Black Widow!

Few creatures conjure up more irrational fear in people all over the world than spiders. And few spiders are more feared (particularly in the United States) than the ominously named subject of this entry into our Creepy Crawler Carnival.

Creepy Crawler Carnival #3

Black Widow
Latrodectus hesperus

For the sake of relatives that will be visiting us soon, I won't mention where I found this spider. Suffice to say, she was not inside the house. I was actually wondering how long it would be before I saw my first Black Widow. Sonja first spotted it last night, but just stood back and pointed at it. It was pretty dark outside, and by the light of our headlamp I wasn't quite sure what kind it was until I got pretty close. Then I saw the red hourglass on her abdomen.

I readily admit that my first reaction when I saw that was to flinch. My heart started racing and that irrational, primal fear started to emerge. I knew we would eventually find some of these around our house, but I was surprised how creeped out I was by it. All I could think of as I fell asleep that night was the fact that there was a "deadly spider" living outside our home. But I know better. I'm a biologist, for crying out loud. I know that the chances of getting bit by one are almost nonexistant...unless I go out and start poking it. I am concerned about our pets getting bitten, though. Particularly Annie, due to her small size and the fact that she likes to play with crawlie things. I think it was just because it was the first one I had ever seen. Cuz tonight, as I was taking these pictures, I was much more fascinated by her than repulsed. As you can see, she really is a stunningly beautiful creature (only the females of the genus look like this...the males are less than half this size).

So, black widow spiders (this one is a western black widow) are surprisingly common throughout the United States, and even into Canada. The genus (Latrodectus) is found worldwide, with all species possessing a powerful neurotoxin (the same type of venom found in cobras and coral snakes). Despite the potency of this venom, bites from these spiders rarely result in death, due primarily to the tiny fangs (less than 1mm long) and the miniscule amount of venom injected. The bite of a black widow results in the clinical syndrome known as latrodectism (named for the genus of which these spiders belong). As the name "neurotoxin" implies, it affects the nervous system, causing convulsions and intense pain. You can compare this to hemotoxin, such as that possessed by rattlesnakes and other pit vipers, that affects the blood.

Black widows tend to prefer living in the clutter that people often surround themselves with and as a result, out of all the venomous spiders in the world, more people are bitten by them than any of the more dangerous species. However, according to Wikipedia (and if it's on Wiki, it's gotta be true), there have only been 63 confirmed deaths from black widow bites in the U.S. between 1950 and 1989. That's well under 1% of reported bite victims.

I also thought this was interesting (taken from Wiki's black widow spider page):

Improvements in plumbing have greatly reduced the incidence of bites and fatalities in areas where outdoor privies have been replaced by flush toilets. Nearly ninety percent of the black widow bites reported in the medical literature of the first 4 decades of [the twentieth] century were inflicted on the male genitalia by spiders lurking underneath the seats of outdoor toilets.
Good thing there are no black widows living in Fairbanks, eh?

Black widows are surprisingly shy. When I tried taking a second picture of her she quickly disappeared under the eave, only emerging again after this moth flew into her messy web.

I really like this picture, since you can see her very characteristic body shape. I got to watch her wrap up this moth for a couple minutes, until she decided she wanted a bit more privacy and carried it back under the eave.

Finally, I thought I'd add a photo of our thermometer that Sonja took on Sunday. Since we moved here, we've broken 100 degrees three times, all within the last week. This is pretty unusual for early May, though. Normal highs this time of year are about 10 degrees cooler. It shouldn't be getting that hot until later in June and July. Even so, the temps really aren't as bad as I thought...unless you're stupid enough to stand out in the sun. Then it sucks. But as soon as you find some shade it's surprisingly comfortable.


Daniel said...
This comment has been removed by a blog administrator.
Sarah Renslow said...

I dont really trust winkapidea! Did you know that any one in the world can add things to it. Well that is what my Reading teacher said that is alsomy computer teacher! You know Im not that freecked out at looking at this pictures any more! You know how you said they are in Canada well are they in Minnesota? My mom saw a hairy quarter size spider with long legs and white spots do you know what that could be.? Im glad I did not see it!!! Have fun in those temps I would be out there tanning riight now. So ummmmmmm bye

Patrick Belardo said...

What is that Daniel guy talking about?

Cool pics... my dad found one in our backyard shed when I was a toddler, but I've never really seen one myself. But, spider + genitalia = my worst nightmare.

Shouldn't you buy a thermometer with a higher upper range? :)

P. Ollig said...

So, Daniel, or should I say Spammer? Yeah, buh-bye. *deleted*

Sarah, glad to hear you're not getting as creeped out by these anymore. Seriously, even black widows shouldn't be that scary. They're so shy that you really need to harass them before they'll bite you. And, with wikipedia, while it's true that anyone can add stuff to it, if you look closely you can see lists of citations added to the bottom of some of the more reputable entries. That's a sign that the person who wrote it may actually know what they're talking about.

And, Patrick, I knew some people would, erm, enjoy(?) that story. I've lived a lot of places where black widows can be found, but this was the first one I'd ever seen. I heard an arachniologist (is that what they're called?) once say that there probably wasn't a home in southern California that didn't have at least 15 black widows living inside it. It's surprising how widespread their range really is.

And I'm hoping against hope that our thermometer will be adequate!

Anonymous said...


Erin said...

We have all sorts of black widows around here. You should come check them out! We had quite a few brown recluses at the farm house. Lots actually. Luckily we didn't see most of them until they were dead.

Anonymous said...

Black widows and genitalia?? Read SKINS by Adrian has a crazed black widow bite scene.