Northern black widow spider

Description

Latrodectus variolus, the northern black widow spider or northern widow, is a species of spider in the genus Latrodectus of the family Theridiidae. The population is closely related to the southern black widow, Latrodectus mactans, and the western black widow, Latrodectus hesperus, of the genus. It is commonly found in Middle Atlantic states (New Jersey, Delaware, Maryland) of the United States. During the April–May mating season, it can travel north along the coast as far as Massachusetts. It is also found in Connecticut in the late summer, and rarely, in southern Ontario and southern Quebec,Canada, 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.The LD-50 has been measured in mice as 1.20–2.70 mg (0.019–0.042 gr); each spider contains about 0.254 mg (0.0039 gr) of venom. Unlike for the related Latrodectus mactans, as of 2015 no antivenom was available Latrodectus is a broadly distributed genus of spiders with several species that, together, are commonly known as true widows. This group is composed of those often loosely called black widow spiders, brown widow spiders, and similar spiders.However, such general "common names" are of limited use, as the diversity of species is much greater. A member of the family Theridiidae, this genus contains 34 species,which include several North American "black widows" (southern black widow Latrodectus mactans, western black widow Latrodectus hesperus, and northern black widow Latrodectus variolus). Besides these, North America also has the red widow Latrodectus bishopi and the brown widow Latrodectus geometricus, which, in addition to North America, has a much wider geographic distribution. Elsewhere, others include the European black widow (Latrodectus tredecimguttatus), the Australian redback black widow (Latrodectus hasseltii) and the closely-related New Zealand katipō (Latrodectus katipo), several different species in Southern Africa that can be called Button spiders, and the South American black-widow spiders (Latrodectus corallinus and Latrodectus curacaviensis). Species vary widely in size. In most cases, the females are dark-coloured, but some may have lighter or even reddish bodies. Many can have red, white or brown markings on the upper-side (dorsal) of the abdomen.