Latrodectus mactans

Description

The Black Widow Spider is one of the most feared in North America because its venom is powerful enough to make humans very ill. This spider has been given its name because of the misconception that the female always eats the male after mating. Sometimes the male escapes unharmed.

The Black Widow is a member of the cobweb weaver family. The female Black Widow is 3/8 inch long and has legs and cephalothorax that are black. Its teardrop shaped abdomen is shiny black with a red "hourglass" mark on the underneath side.

The hourglass is easy to see because the spider hangs upside down in the tangled, but strong web. Sometimes there is a red spot near the spinnerets and even small red streaks or spots on the back of the abdomen.

The harmless male of the species is 1/8 inch long, with red and white markings on the abdomen.

Habitat

Black Widows are found in many areas of the United States, but they are most common in the South. This spider prefers a dark, damp habitat. It is most often found outside, but can be found inside in dark places inside dwellings such as sheds, garages, and closets.

The female rarely leaves the web and will bite only when she is bothered. The small, oval egg cases are tan in color, papery in texture and are found hanging in the web. The female will aggressively guard her egg sacs.

Food

The strong silk of the Black Widow's web is perfect for catching crawling and hopping insects such as crickets, grasshoppers, and flies.

It spins its strong, tangled web close to the ground in crevices such as between rocks in rock piles, in holes of stacked bricks, between logs in woodpiles, in tree stumps, trash piles, and other similar places.

While the core of the web may be small, there are snare lines that project from it that can be a few inches to a few feet long.

Defense

Although the Black Widow is a shy, nocturnal spider (that likes to hunt for prey at night), it will bite in self-defense or if pressed against a person's body. When the threads of the web are disturbed and the spider thinks that it has caught prey, it will rush out and bite.

The venom of the Black Widow is a neurotoxin, which is a "nerve poison" to its prey. Sometimes if it is threatened, the spider may run to one side of the web or stay perfectly still. The black color of the spider helps it blend in with the darkened environment where it lives.