Details
Latrodectus mactans
The black widow spider is a glossy black cobweb spider of southern North America. Females are known for the red hourglass mark and potent venom, though they usually stay hidden.
Map: Ecoregions 2017 © RESOLVE (CC BY 4.0) · Natural Earth (PD)
It occurs from the southern United States into Mexico around grassland, dry edges, sheds, stonework, debris and towns. Webs are built in dark, undisturbed crevices.
Females are about 1 cm in body length and over 3 cm across the legs. A shiny black body and red hourglass on the underside are typical, while males are smaller and paler.
Nocturnal and solitary, it waits in an irregular three-dimensional web. It usually retreats when disturbed but may bite if pressed or trapped.
Small insects and other arthropods are caught in the web. Silk wraps the prey, and venom subdues it before fluids are consumed.
Females make round egg sacs and guard them within the web. Young disperse after hatching and later build solitary webs.
Bites can cause pain and muscle symptoms, so handling should be avoided. Around buildings, gloves and reducing clutter lower the chance of accidental contact.
