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Latrodectus, The Black Widow Spider

A female black widow spider

She only requires some respect from you, and you'll be fine. ~pinky swear~

She only requires some respect from you, and you'll be fine. ~pinky swear~

Spiders are forever maligned by humanity, and none is more maligned than the black widow spiders. Forever the black widows are associated with Halloween, and are readily seen on decorative Halloween displays. They simply evoke fear, and I think this is due to their coloring. No mistake about it, the coloring of the black widow is towards your benefit.

There is usually something to the vernacular names of creatures, and there certainly is with all spiders of the Theridiidae family, the family of widow spiders. They aren't called widows for nothing. Another impression from the name black widow would be that all of them are female, and of course this is impossible. What is significant is the females of the black widows have especially large venom glands, and in fact, only the female black widow spider has a bite dangerous to humans. The black widow's venomous bite is only rarely fatal; properly respect the black widow, and I assure you you'll be fine.

Male and female black widows. She's the large and deadly one, to him, and to you


Sexual dimorphism is a fancy phrase with a simple meaning. All the term describes is the difference in size between males and females of a particular species. With black widow spiders the female is much, much larger than the male, so sexual dimorphism is pronounced in the species. Of course black widow females often kill and eat the males they mate with; but this behavior is hardly unique to black widows. The sexual cannibalism in Latrodectus is something often observed in enclosed environments, environments where the male has no avenue of escape. The behavior may not be so common in the wild, for the obvious reason. That said, the females who do kill and eat the males they mate with tend to have children who are more aggressive, and thus, more effective survivalists. Mom just wants what is best for her children. Some of the offspring typically eat some of the siblings.

There are thirty three species of Latrodectus, or widow spiders in this world, and spread out within in. The hourglass markings on the abdomen are evident in most all of the species. Usually these markings are in some shade of red or another.

Black widow spiders are far more dangerous than brown recluse spiders, and far far more dangerous than wolf spiders. You are also far less likely to ever get bitten by a black widow than you are the wolf or the recluse. Black widows are more reclusive than brown recluses; and truly, you have to know something about their proclivities to ever even find one. Also unlike the wolf and recluse spiders, the black widows are orb spinners, spiders of the web.

Baby black widow spiders - they aren't black yet

Some of these are likely to be eaten by their siblings, isn't that sweet?

Some of these are likely to be eaten by their siblings, isn't that sweet?

The black widow on its web


It is for good reason I have respect, but little fear of black widow spiders, including the sometimes deadly females. Having spent years and years as an hvac service tech guy, I happen to know black widows love to spin their webs inside of air conditioning condensers, the big thing with the fan on top that blows hot air outside your home. Yes, they absolutely love the comfy and secluded confines underneath the condenser fan motor. They spin their webs attached to copper tubing inside the condensers, and many many times I've got to put my precious hands within an inch or so of the spiders themselves. Never once have I been bitten, and in fact, so long as I'm aware of the position of the spider and my hands, I know for sure there is no reason to fear. The spiders simply won't bother you unless you bother them. Another reason black widows find a/c condensers so fine for homes is they nearly always spin their webs and make their homes about one foot from the ground.

While wolf spiders have terrific eyesight, black widows do not. They sense danger in other ways, and when they do they often lower themselves to the ground from their suspended orbs, and flee. Like almost any other spider, black widows have no desire to waste their venom or energy on you.

So far as eating goes, the black widows spin their webs, and simply wait for a dumb insect to get caught in the thing. Following a catch, the usual occurs, the spider injects the trapped insect with venom, which liquefies the insects insides, and the spider wraps the thing up for safekeeping. What else, then, can be said of the black widow's silk? For its thickness, it is as strong as steel. Steel of that same thickness, however, is quite a lot denser, and thus heavier. Pound for pound, the black widow's silk is far stronger than steel, it is also stronger than most any other type of spider's silk.

Black widow spiders are very territorial. It is very unlikely you will ever see a black widow infestation within a home, these spiders do not wish to live inside your home, as there is little for them to find to eat inside a clean house or apartment. If you're home has black widows inside, then the issue is likely the general lack of cleanliness within. As the spiders are territorial, there won't be a group of them congregating, i.e., there won't be a literal infestation.

Steatoda, the false widow spider

Steatoda may be a 'false widow' spider, but this spider is also potentially deadly.

Steatoda may be a 'false widow' spider, but this spider is also potentially deadly.

The black widow spider bite and tissue damage


Black widow spider bites.

Does the false widow spider picture above look fierce and frightening to you? It should, and just as there are many species of Latrodectus, there are many species of Steatoda, all venomous. The Steatoda genus of spiders aren't so harmful to humans; but then some humans react more negatively to any spider bite than will another individual human. In the cases of either of the types of spiders and their venomous bites, usually no medical attention is required. In other cases hospitalization may be required. If you know you've been bitten and you are feeling quite unwell, then you should certainly take yourself to an emergency room.

If you get a black widow spider bite, you may experience some or all of these symptoms:

  • painful bite (but not always)
  • two tiny fang marks, possibly a little red mark, maybe some swelling (but sometimes there’s no evidence of the bite)
  • muscle aches and cramping of the abdomen, back and extremities that can be severe
  • increased sweating or salivation
  • elevated blood pressure
  • rarely, seizures or respiratory difficulties that can result in death, usually in children.
  • symptoms usually peak within about 12 hours but can continue for several days
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© 2016 Wesman Todd Shaw


Wesman Todd Shaw (author) from Kaufman, Texas on October 02, 2018:

That is absolutely one of the scariest parts of the job for me. I'm not tall, and I'm thin. I'm always THE GUY sent into the places where you know the home or business builder spared nary a thought for the young hvac, plumbing, and electrical service folks.

You know, they call the brown recluse a recluse. So far as I can tell, the black widow is at least as reclusive. It's why they love the inside of a condenser so much.

It's sure wise to be afraid of angering a black widow, but I'm not even sure how to go about getting a rise out of one. I bet a vegan could piss one off. Vegans can piss any non vegan entity off.

Heh. You know, I've never known of someone to get bit by a black widow. I do know a Lady who had to have some serious surgery for a brown recluse bite though.

promisem on October 02, 2018:

As an hvac service guy, you'll appreciate how we recently moved into an older home with a crawl space and found a couple of black widows hanging around the vents at the base of the house. Apparently they were living in the crawl space.

Every time I turned on a water faucet, I looked all around for one in case it was ready to leap on me and give a fatal bite. After a year and a half, I haven't seen any more.

It gave me some newfound respect for hvac people who have to go into crawl spaces to fix problems. I sure wouldn't do it.

Wesman Todd Shaw (author) from Kaufman, Texas on January 17, 2016:

Hey Chef! You provided me a really good idea on how to improve this article!

Here is a great image. To me....they look like just about every other spider eggs though.

Lee Raynor from Citra Florida on January 12, 2016:

Hey Wesman

Very useful Hub here. We have a lot of Black Widows in Florida, I just killed one in a can of potting soil that I frequently stick my hands in. All in all, in spite of their deadly reputation I've never been bitten but I've encountered them many many times.

Are the eggsacs identifiable? I've seen a lot of eggsacs that I thought were black widow eggs but not sure. The eggsacs I thought were B. widows look like small white peas with little spikes?

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