Thursday, May 21, 2009


I went out for a random night foray and saw a lovely black widow sitting in a corner. I tried to find food for her, but unfortunately beetles tend to fall through their very haphazard webs. The males are smaller and do not have the red hourglass shape on the abdomen. They court the female by bringing a dead insect as a nuptial gift, but of course run the risk of being eaten themselves. I have always liked black widows, since they are beautiful spiders, somewhat dangerous, and very cool hunters. I had the pleasure of capturing one and I threw a crane fly (tipulidae) into the jar with it. The crane fly was flying very fast and erratically, and the black widow was sitting at the bottom, a sticky thread between her front pair of legs, and in a split-second she lunged at the crane fly and caught it with the string. It was really remarkable - they have such amazing reflexes. Here are the lovely pictures.

Arachnida; Araneae; Araneomorphae; Entelegynes; Theridiidae; Latrodectus hesperus
Common Name: Western Black Widow

The family Theridiidae contains cobweb spiders, which spin webs that are three-dimensional or mesh sheets, instead of a traditional orb web. Usually these spiders have eight eyes, rarely six. The genus Latrodectus, which contains black widows, is widespread in the US. The venom is a neurotoxin, and symptoms of envenomation include swelling of the lymph nodes, profuse sweating, rigidity of the abdominal muscles, facial contortions, and hypertension. Antivenin is readily available, and no deaths have been linked to black widows since the 1940s. For more information on the biology of black widow venom, see my medical blog.


  1. I was always afraid of spiders, especially black widows, which we encounter all the time here in Sacramento and also at our home in El Sargento, Baja Sur, Mexico. But when I found we had black widows, 6 inch long scorpins, giant wolf spiders, and rattle snakes on our Baja propety I started to learn to enjoy them. I have the feeling that tiny baby blackwidows are running all over our yard in Sacramento. I can take a small flower pot and turn it upside down anywhere in our yard. If I leave it alone for a month, then turn it over, more often than not I will find a black widow spider has taken up residence inside. A friend in Baja recently came in from kite surfing and tossed her wet suit on the ground. A few hours later she put it on to go surfing again. She felt a sharp pain on her thigh and mashed her wet suit to kill whatever bug might have gotten her. While surfing she started feeling strange, had difficulty breathing and started sweating. When she came ashore and took off her wet suit her thigh was black and out spilled a dead black widow. The village clinic had no antivenom. She was sick for a couple of days but recovered.

  2. Wow, I hate, absolutely hate spiders! But this black widow is beautiful, absolutely gorgeous! If I saw it in my house I would flee and later come back to kill it with a shoe. Anyways, maybe I wouldn't with this one. As long as she was out of my way and I never saw her.

  3. Thanks for all the comments =) I was actually a little disappointed with the pictures because I usually take closer pictures with better lighting, but I was a little nervous to get too close since I didn't now how it'd react to the flash.