Black Widow

Latrodectus is a broadly distributed genus of spiders, which is composed of both black widow spiders and brown widow spiders.[3][4][5][6] A member of the Theridiidaefamily, this genus contains 31 species,[2] including the North American black widows (L. mactans,L. hesperus, and L. variolus), the European black widow (L. tredecimguttatus), the Australian redback black widow (L. hasseltii) and the button spiders of Southern Africa. Species vary widely in size. In most cases, the females are dark-coloured and readily identifiable by reddish markings on the abdomen, which are often hourglass-shaped.

These small spiders have an unusually potent venom containing the neurotoxin latrotoxin, which causes the condition latrodectism, both named after the genus. Female widow spiders have unusually large venom glands and their bite can be particularly harmful to large vertebrates, including humans. Only the bites of the females are dangerous to humans. Despite their notoriety, Latrodectus bites are rarely fatal or even produce serious complications.