Black Widow Spider

Latrodectus mactans

Venomous black spider with distinctive red hourglass marking on abdomen.

Insect Extreme Risk

About Black Widow Spider

Black widow spiders are highly venomous and one of the most recognizable spiders in North America. Females are about 1/2 inch long (not including legs) with a shiny black body and distinctive red hourglass marking on the underside. Males are smaller, lighter colored, and not dangerous. They build irregular, tangled webs in dark, undisturbed areas. They're shy and bite only when threatened or accidentally contacted. Bites contain neurotoxic venom that affects the nervous system. They prefer dark, dry, sheltered locations and are most active at night.

Identification

Female: shiny black, 1/2 inch body length. Distinctive red or orange hourglass on underside of abdomen. Eight eyes in two rows. Large, bulbous abdomen. Male: smaller, brown, harmless.

Signs of Infestation

Irregular, tangled webs in undisturbed areas. Egg sacs (cream-colored, papery spheres). Spiders in dark corners, woodpiles, sheds, or garages. Web with the spider hanging upside down. Males don't build webs.

Health & Safety Risks

Black widow venom is 15 times more toxic than rattlesnake venom. Bites cause severe muscle pain, cramping, nausea, breathing difficulty. Symptoms intensify over 8 hours. Rarely fatal but requires immediate medical attention, especially for children, elderly, and those with health issues.

Prevention Tips

Eliminate clutter in basements, garages, and storage areas. Seal cracks and crevices. Shake out shoes and gloves before wearing. Wear gloves when working in sheds or moving stored items. Remove webs regularly. Keep firewood away from home. Install door sweeps.