Thirty-one species of latrodectus, or widow spiders, are thought to exist worldwide. Of these known species, four types are native to the United States and a fifth has established itself as an introduced species since 2000. One or more of these species can be found almost everywhere within the U.S. and southern areas of Canada.
Red Widow Spider
The red widow is an uncommon species found exclusively in Florida. The species has a black abdomen with red dots surrounded by yellow circles and its legs and head are red in color. Its natural habitat is dry scrub land and it is only found in a few such areas in the wild. It is a semiaggressive species with a painful, venomous bite.
Western Black Widow
The western black widow resembles the iconic look of the species, being all black except for the small red hourglass marking on the abdomen. As the name suggests, the species is native to the western U.S. from southern Canada all the way down into northern Mexico and as far east as Texas and Oklahoma. Tending to stay away from humans, the spiders can be found anywhere from a hole in a tree to a crack in a rock.
Southern Black Widow
The southern black widow looks very similar to the western, but is slightly larger on average. Native to the eastern U.S., the species can range from New York down into Florida and as far west as Texas. The species is less timid of human activity and can be found in disused outbuildings and woodpiles. The species only bites in defense and a single bite is rarely fatal.
Northern Black Widow
The northern black widow only differs from the southern in that its hourglass marking is not complete, with there being a gap between the top and bottom. Found throughout the same range as the southern it is found a little further north in parts of southern Canada. It is also a little more timid and less frequently found near humans.
Brown Widow Spider
The brown widow is an invasive species which is thought to have found a population foothold in early 2000. It is a mottled brown color looking little like the native black widows except in body shape. Possibly from South America or Africa, it is found in Southern California and is slowly spreading. It does have a venomous bite but it is weak in comparison to the country's other widow species.