Black Widow

Black Widow

Black widows are identified by red hourglass markings on the underside of their abdomens. Black widows are shiny black in color. Females are larger than males and can measure up to 10 millimeters in length. These spiders are members of the genus Latrodectus.

Not all adult female black widows exhibit the red hourglass on the ventrum or underside of the abdomen — some may have a pair of red spots or have no marking at all. Female black widows often exhibit various red markings on the dorsal or top side of the abdomen, commonly two red spots. However, it is believed that black widow young have at least some sort of marking on their abdomens. Adult male black widows are a quarter the size of the female, and are usually gray or brown rather than black and red; while they may sometimes have an hourglass marking on their ventral abdomen, it is usually yellow or white, not red. The bite of a male black widow is not considered dangerous to humans; it is the bite of the adult female black widow from her much larger venom sacs that has given this spider its dangerous reputation. While there is great variation in specifics by species and by sex, any spider exhibiting a red hourglass or a pair of large red round spots on the ventral abdomen with an otherwise black shiny body is an adult female black widow. The bright red hourglass & spots are never located on the dorsum, which is the more visible aspect; the identifying features are on the underside, anatomically known as ventrum; i.e., the spider must be lying on its back to reveal the markings.

 

Black widows in las vegas, henderson, boulder city, summerlin, and north las vegas, Nevada.