''Latrodectus variolus'', the northern black widow spider or northern widow, is a venomous species of spider in the genus '' Latrodectus'' of the family

Theridiidae Theridiidae, also known as the tangle-web spiders, cobweb spiders and comb-footed spiders, is a large family of Araneomorphae, araneomorph spiders first described by Carl Jakob Sundevall in 1833. This diverse, globally distributed family includes ...

. The population is closely related to the southern black widow, '' Latrodectus mactans'', and the western black widow, ''

Latrodectus hesperus ''Latrodectus hesperus'', the western black widow spider or western widow, is a venomous spider species found in western regions of North America. The female's body is 14–16 mm (1/2 in) in length and is black, often with an hourglass-shape ...

'', of the genus. In North America, the species is commonly found in Middle Atlantic states (

New Jersey New Jersey is a U.S. state, state located in both the Mid-Atlantic States, Mid-Atlantic and Northeastern United States, Northeastern regions of the United States. Located at the geographic hub of the urban area, heavily urbanized Northeas ...

Delaware Delaware ( ) is a U.S. state, state in the Mid-Atlantic (United States), Mid-Atlantic and South Atlantic states, South Atlantic regions of the United States. It borders Maryland to its south and west, Pennsylvania to its north, New Jersey ...

Connecticut Connecticut ( ) is a U.S. state, state in the New England region of the Northeastern United States. It borders Rhode Island to the east, Massachusetts to the north, New York (state), New York to the west, and Long Island Sound to the south. ...

Maryland Maryland ( ) is a U.S. state, state in the Mid-Atlantic (United States), Mid-Atlantic region of the United States. It borders the states of Virginia to its south, West Virginia to its west, Pennsylvania to its north, and Delaware to its east ...

). During the April–May mating season, it can travel north along the coast as far as

Massachusetts Massachusetts ( ; ), officially the Commonwealth of Massachusetts, is a U.S. state, state in the New England region of the Northeastern United States. It borders the Atlantic Ocean and the Gulf of Maine to its east, Connecticut and Rhode ...

in summer, and rarely, in southern

Ontario Ontario is the southernmost Provinces and territories of Canada, province of Canada. Located in Central Canada, Ontario is the Population of Canada by province and territory, country's most populous province. As of the 2021 Canadian census, it ...

and southern

Quebec Quebec is Canada's List of Canadian provinces and territories by area, largest province by area. Located in Central Canada, the province shares borders with the provinces of Ontario to the west, Newfoundland and Labrador to the northeast, ...

, Michigan, and at least as far northwest as parts of Wisconsin. A bite may cause latrodectism, and requires medical attention in the case of increasingly severe discomfort or spreading local redness accompanied by severe pain. Other symptoms, which can last up to a week, may include body aches, severe pain, fever, inflammation, nausea, and vomiting. Bites to humans are not typically deadly except in infants and the elderly. The LD-50 has been measured in mice as ; each spider contains about of venom. Unlike for the related ''Latrodectus mactans'', no antivenom was available.

References

External links

* variolus Spiders of North America Spiders described in 1837 {{Theridiidae-stub