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.