Northern Black Widow

The northern black widow is a close relative of the more familiar southern black widow, occurring across the northeastern and north-central United States and into southern Canada. Adult females are shiny black with a rounded abdomen, but unlike the solid hourglass of the western and southern species, the northern widow typically shows the mark split into two separate triangles or dashes on the underside, along with a row of red or orange spots running down the top of the abdomen.

This species tends to be more closely tied to natural habitats than to buildings, favoring brush piles, hollow stumps, stone walls, and dense low vegetation at the edges of woodlands and fields rather than garages and sheds. It is generally considered shyer and less likely to be encountered around homes than other North American widow species.

Like other widows, it constructs a tangled, irregular web close to the ground and plays a role as a predator of small insects, helping to keep local arthropod populations in check.

• Adult female: glossy black, rounded abdomen with a row of red or orange spots along the top midline
• Underside marking is typically broken into two separate red triangles rather than a solid hourglass
• Long, slender black legs
• Males: small, tan-brown with pale striping, rarely noticed
• Lookalikes: southern black widow (solid hourglass), false widow spiders (Steatoda, duller brown-black, no true hourglass)

Ranges across the northeastern and upper midwestern United States and into adjacent Canadian provinces. It is most often found in wilder settings than other widows - brush piles, rock walls, hollow logs, tall grass, and abandoned outbuildings at woodland edges - rather than actively inhabited structures.

The northern black widow is a sedentary web-builder that hangs inverted in its tangled snare, feeding on flying and crawling insects that become trapped in the sticky silk threads. It is nocturnal and reclusive, retreating to a silk retreat within its web during the day and becoming active in low light. As with other widows, diet is made up of ants, beetles, flies, and other small arthropods captured in the web, and sexual cannibalism after mating has been documented but is not universal.

Females spin one or more spherical, papery egg sacs over a season, each holding numerous eggs, and often guard the sac near the web. Spiderlings hatch and disperse on silk threads carried by the wind, a behavior known as ballooning. They pass through several juvenile molts before reaching maturity, with females growing larger than males. Adults are most active in warmer months, with many populations overwintering as egg sacs or immature spiders in sheltered sites, resuming activity as temperatures rise in spring.