Spiders

The common name widow spiders is applied to members of the genus even though the males are not usually eaten after mating and can even go on to fertilize other females. The Black Widow spiders are well-known members of the genus. The female black widow’s venom is particularly harmful to humans (males almost never bite humans). The injection of venom from these species is a comparatively dangerous or lethal spider bite, resulting in the condition Latrodectism which is named for the genus.

Spiders of the genus Steatoda (also of the Theridiidae family) are often mistaken for widow spiders, and are known as false widow spiders. The false widow spiders are significantly less harmful to humans.

Along with the southern, western and northern black widows (Latrodectus mactans, Latrodectus hesperus and Latrodectus variolus) with the famed red hourglass, the gray or brown widow spiders (Latrodectus geometricus), and the red widow spiders (Latrodectus bishopi) (Preston-Malfham, 1998) are also found in the United States. But there are widow spiders on every continent of the world except for Antarctica. The single species occurring in Australia, Latrodectus hasselti, has Redback as one common name; African species of this genus are sometimes known as button spiders.