Wikijunior:Bugs/Ant-Mimicking Spider

What does it look like?
Ant-mimic Spiders are between 1/8 inch and 3/8 of an inch long. Adult females are slightly larger than males. They resemble ants in shape and color. They are called “ant mimics” because they have a “false” waist and they move like ants. Their color is mostly reddish-brown, but they can also be orange, brown, or black. There are often light or dark bands or spots on the body. Reflective hairs make them look shiny like ants. The hard, outer covering (carapace) is pear-shaped and dark with white or yellow hairs. Eight eyes are arranged in 2 horizontal rows with violet color around them. There are white spots behind the rear eyes.

Where does it live?
Members of the longipalpa species of Ant-mimics live in soil, under leaves, and inside tree bark, where they construct small silken homes. They are often found near anthills and behave like ants to confuse predators. Their habitats are woods, meadows, and gardens. They are sometimes found inside buildings. They range from Quebec in the north, to Florida in the south, and west to Texas and Nebraska.

What does it eat?
Ant-mimic spiders eat ants, small arthropods, and insects.

How does it defend itself?
Ant-mimic Spiders make quick darting movements that make them look like ants. Looking like an ant keeps them from being eaten by real ants. Their colors show predators that they might sting or taste bad. Some species imitate wingless velvet-ant wasps which are known to have a very painful bite.

What stages of metamorphosis does it go through?
Ant-mimic Spiders mature and mate in summer or fall. At egg-laying time, the female attaches flat egg sacs beneath a stone or in a rock crevice. Egg sacs are white and shaped like a flattened disk. The egg sacs contain relatively few eggs. The eggs hatch in autumn. Spiderlings overwinter and disperse quickly in spring.

What special behaviors does it exhibit?
Ant-mimic Spiders exhibit Batesian Mimicry. That is, they imitate behavior and appearance of ants. The longipalpa species slowly wave their two front legs in the air like carpenter ant antennae.

Members of the longipalpa species do not spin webs to capture prey. Instead they roam around hunting for food or mates. Some build temporary homes by weaving a tubular sac of silk inside a rolled-up leaf or under plant matter.

How does this bug affect people?
A bite from an Ant-mimic Spider poses little risk to people. It is similar to a bee sting. But people with allergies may be harmed if bitten.