Latrodectus hesperus
(Western Black Widow)

Picture ID 75551

Picture of Latrodectus hesperus (Western Black Widow) - Dorsal

Comments & ID Thoughts

I think it's a lactrodectus geometricus, or brown widow. I noticed it after I set some wood down that I had picked up. It did bite me, and I've had symptoms similar to the time I was bitten by a black widow.

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This is a juvenile western black widow, Latrodectus hesperus. They get more black as they grow. Juveniles and males are harmless.


I think you have a good point. I tried Googling it and I the impression I got was that males and juveniles have smaller fangs and less venom than adult females. Nothing says that they don’t have any venom. They should have venom in order to protect themselves and kill prey. It could be low enough to be considered harmless. When we say that we aren’t including the rare cases of people with very weak immune systems or venom allergies being bitten. Since you’ve had the venom from a female in your body before that should raise your risk of… Read more »


There is no documented instance of “venom allergies” from spider bite.


Thank you, that’s interesting. I tried finding out what the situation is online. Can you cite a source? I want to be sure we tell people the most current and accurate info. I found medical sites referring to anaphylaxis, but medical professionals say to not trust those sites to be correct. There seems to be confusion about what a normal “toxic reaction” is and whether it is a different thing than an allergy. Nobody mentioned “sensitivity,” as in, I have a sensitivity to nickel, it’s not a true allergy. Open discussion to everyone: Please post links to reputable research as… Read more »


You’re asking me to prove a negative. Instead, why don’t you try citing an example in the medical literature of any case of allergy to spider bite.


I know. I only found generalizations. You’re the first person to bring up this concept in the site’s discussions. I don’t want to argue, just learn what I can. The examples in medical literature apparently aren’t reliable as to the sources of the allergic reactions. I didn’t find any documented experiments on humans to find someone with a spider venom allergy. Spiders have varying venom chemistry which can be a variable in reactions also.

Additional Pictures

Picture of Latrodectus hesperus (Western Black Widow) - Dorsal Enlarge Picture
Picture of Latrodectus hesperus (Western Black Widow) - Male - Dorsal Enlarge Picture
Picture of Latrodectus hesperus (Western Black Widow) - Lateral Enlarge Picture
Picture of Latrodectus hesperus (Western Black Widow) - Dorsal Enlarge Picture