Brown Widow

Posted by kahunna
October 1, 2008

While walking to the end of my private street to get the mail, I passed an unusual sighting: a brown widow (Latrodectus geometricus).  I’ve seen many black widows – there everywhere in Southern California – but never a brown.  Here’s an interesting fact about the spiders:

The name “widow spiders” came from the belief that the female usually killed and ate the male after mating. It is now known, however, that this practice of “husband killing” was an artifact of the conditions under which observations were made. In early behavioral studies, the male widow spiders were kept in small containers with the females and they could not leave after mating. The usual result was that at some point, the female would mistake the male for prey and he would be eaten. Subsequent studies, both in the laboratory and the field, have shown the female eating the male rarely occurs so long as he is able to leave her web after mating. Interestingly, there is one spider in the same group as the American widow spiders, the Australian redback spider (Latrodectus hasselti), where the female actually begins eating the male as part of the mating ritual. However, this is a unique example among the spiders.

[Source: Virginia Tech Department of Entomology]

Brown Widow

Brown Widow

Brown Widow

Brown Widow

Brown Widow

Brown Widow

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  • Al
    jhbfgsjkg, I got you beat! I have killed hundreds this last week. And have a jar of egg sacs! (in paint thinner) I too am tempted to flame thrower my back yard. As it is I use my soldering torch at night. Problem is the torch can blow the sacs away out of sight. So I use a stick to grab the sacs and put them in a jar of whatever is lethal. I cannot believe the numbers! It's ridiculous.
    Here's the problem for me, the Brown Widow info is so varied. They are all over the US now. Infestation level. Most of the info seems to be cut and paste from Black Widow facts. That's not workin' for me. If they are "almost" as poisonous as Black Widow, with the Brown Widow sky high numbers why aren't there tons of hospital reports? Makes me think (and I want to think) that they are not near as poisonous as their cousins, not just because they aren't aggressive and don't bite. Why and how are there not concrete facts on the Brown Widows? Blows my mind.

    Kahunna do you still need specimens?
  • Hey Al,

    Sounds like you're living a 1950s horror film! I picture you running around scorching your yard with your soldering torch, frying spiders which blanket everything in sight! Try to keep in mind that spiders are beneficial to yards and gardens by feeding on harmful insects. Having a couple spiders around isn't a bad thing.

    I think the major difference between the brown widow and the black widow, in my opinion, is that the brown widow is more docile and less likely to bite when bothered. I find them very easy to catch since their first reaction when approached is to play possum. However, when I've approached a black widow, they move violently, sometimes towards the catching jar or stick, holding up their front legs with their fangs exposed.

    Another way I look at it is that the black widow is like a wild panther while the brown widow is a house cat. They might be related genetically, but act much differently.

    Al, if you want to share your specimens for scientific research, contact the Arachnid department at Georgia Southern University.
  • ljhbfgsjkg
    I have killed 12 of these spiders and a lot of egg sacks in the last week. Im half tempted to just flamer thrower my backyard.
  • sarah
    I live in oregon and today I rescued a beautifiully and boldly striped widow with a orange hour glass , I never knew we had brown widows plan on taking photos.
  • I'm in the Baldwin Hills near LAX. We had never seen Browns before this year. First spotted tell-tale egg sacs a few months ago (we quickly disposed of them). Spotted our first adult just a few weeks ago. Since then, we're finding them on almost a daily basis. The Black Widows are still around - haven't seen any depletion on their part (just an explosion by the Browns). Also, found a large Black in the bottom of our beehive. She was sitting next to a Brown egg sac. Assuming they dine on one another -- true?
  • gordonandrew
    I have a specimen of what I thought was a black widow. It is totally black with black legs not striped like the brown widow. It seems to be much larger than the brown widow. The one thing I did notice was a yellow pattern on her back. Red Hour glass (not orange like the dozens of other brown widows). Could the species be interbreeding creating a new type of spider. It is dead now I spayed it with some bug spray because it was under a chair I sit on. Anyone else see this. I am pretty sure its not the brown widow because of all the pictures I have see and what I have read always show the legs as striped not completely black.
  • kpalmal
    OMG – we have “eradicated” hundreds (and I do mean hundreds) over the course of several years. We thought they were just immature and/or mutated black widows (which we also still see). Although, like other anecdotal stories, the black widows seem fewer. Have also seen dozens of their distinctive egg sacs. Live in Sierra Madre.
  • calicougar
    Southern California, L.A. county~ I just killed a brown widow spider and disposed of her EIGHT eggs today! I recognised the familiar tangle of widow spider web on my trash can handle, but was surprised when I saw the unfamiliar, spiked egg sacks. I sprayed the entire mess, and was further surprised when a brown spider with an orange hourglass on the abdomen emerged. Some internet investigation confirmed that the spiked egg sacks were those of the brown widow spider. Southern California is loaded with black widow spiders, but the brown is apparently a recent import. ICK!!! One more poisonous pest to watch for around the house.
  • kayla
    i think that spiders are cool but dangerous!!!!
  • eric
    I live in Orange county, California and Im used to having Black widows all around and I know they're web like the back of my hand. Lately, I have seen their web, but they're all Light brown with white speckles on them. That have the same body type as a widow, Huge abdomen, but no marking on the underbelly? Any thoughts?
  • Hey Eric,

    Is there a way you could send me a photo of this spider? I'll try my best at identifying it. kahunna at gmail dot com
  • admin
    Hi JT - Brown widows spiders were introduced to Southern California sometime around 2003, most likely through commercial imports of plants, flowers, food or furniture. I too have been noticing a great number of the spiders and so have others I've talked to who live in the Los Angeles area. Luckily, they're not as aggressive as a Black Widow and usually curl up in a ball when threatened. From the info I've read online, it's hard to tell how venomous they are compared to the Black Widow, but some African studies show that their bite is as dangerous as a bee sting. Nonetheless, you should consult your physician if you are bitten. Thanks for commenting!
  • JT
    In July 2007 we started noticing brown widows in the neighborhood. They have become well established; too well really. It is usually the distinctive egg sacs you'll notice as the spiders are reclusive. Are there any theories as to their spread into metropolitan southern CA?
  • Misty RESEARCH
    These are great pictures! I'm actually doing research on these spiders and am in DESPERATE need of specimens! If anyone can help please contact me! MSummer6@GeorgiaSouthern.edu THANKS SO MUCH!
  • Takuju
    Great set of macro shots. You have great eyes for both the small and the big.
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