Scientific name: Latrodectus spp. (Fabricius)
Facts: Widow spiders are shy and secretive and found in seldom-disturbed areas. The mature female has a characteristic hourglass-shaped, reddish orange marking on the underside of the abdomen. However, there are four species in this genus in Texas and the markings on the abdomen can be highly variable. It is often difficult to distinguish between the species. Moreover, they are not all black and especially the males and juveniles can have a lot of red, green, white or other colored markings.
Widow spiders are predaceous, devouring small arthropods trapped in their irregular cobwebs. Their bite is relatively painless at first, but may be followed in about an hour by intense pain and swelling. The venom causes nausea, cramps, lack of coordination, and difficulty breathing by interference in nervous functions. Death is uncommon but has occurred in individuals hypersensitive to the venom.