Wikijunior:Bugs/Wolf Spider

What does it look like?
Wolf Spiders belong to the Lycosidae family. Most are dark brown or gray, black, or tan. They are very hairy. Their name comes from the Greek word lycosa meaning wolf. Like all spiders they have 8 legs. They have a combined head and midsection (cephalothorax), and an abdomen. The hard outer covering is called an exoskeleton. It is flexible so the spider can bend and move. They are 1/8 to 1-3/8 inches long. Males are usually smaller than females.

There are 8 eyes. Two eyes are larger than the others. The jaw-like parts near the mouth are used to crush prey. They are called chelicerae and have fangs to inject venom. The long legs have 3 tiny claws at the tip. They have reflectors in their eyes to help them see at night. The light of a flashlight will reflect from the silvery eyes. Thin-legged Wolf Spiders and Burrowing Wolf Spiders have spines on their legs.

Where does it live?
Wolf Spiders live almost everywhere in the world, including the Arctic and the tropics. Around 200 species live in North America. They can be found in mountains, deserts, rainforests, and wetlands. They are common in grasslands and meadows.

Most Wolf Spiders live on top of the ground. Some make holes under rocks. Burrowing Wolf Spiders live in sandy areas where they dig deep burrows in the sand. They cement the burrow walls with silk. They throw loose sand out the doorway. Forest Wolf Spiders and Rabid Wolf Spiders live in ground litter in the woods. Thin-legged Wolf Spiders live on surface soil in grassy fields. They do not build shelters. Carolina Wolf Spiders are found on the ground in open fields. Tropical Wolf Spiders make a sheet-like web for a home.

What does it eat?
Wolf Spiders eat insects and small spiders. Most are hunters and do not spin webs. Some hunt in the day and some at night. They hunt alone and use their keen eyesight to spot prey. Their body hairs can sense touch and vibration. They can detect movement of insects or animals. They move very quickly. They can cover two feet per second when chasing prey. Some sit and wait for prey to pass near the mouth of a burrow. Forest Wolf Spiders use a dragline to hang in midair so they can pounce on their prey.

How does it defend itself?
They blend into the background to hide from predators. Dark, spotted or mottled body colors help them hide in dead leaves and other debris. Some build trap doors over the burrow entrance. They use pieces of moss, dirt, silk, and twigs to camouflage the entrance of the burrow.

What stages of metamorphosis does it go through?
Wolf Spiders undergo simple, incomplete metamorphosis. In most Wolf Spider species, the female lays dozens of eggs. She spins a sheet of silk to lay her eggs on. She rolls them into an egg sac and attaches it to her spinnerets (web-producing organs). She drags it after her until the spiderlings hatch.

There is no larval or pupal stage. There is no “resting” stage before the baby spiderlings emerge from the eggs. They resemble adults when they hatch. They live on the mother’s back for several weeks until they are big enough to hunt on their own. They shed their skin several times as they grow. Most live for several years. They have been known to live up to 11 years.

What special behavior does it exhibit?
Male Wolf Spiders court females by waving their pedipalps (feelers on the face). Some rub their bodies across leaves or click their legs to make sounds. Sometimes the male wraps a fly in silk and gives it to his mate. Different mating signals let the female spiders recognize their own species.

Rabid Wolf Spiders often bask in the sun, keeping warm, ready to pursue prey. Female Burrowing Wolf Spiders warm the egg sac in the sun at the doorway of the burrow.

Wolf Spiders communicate with each other using smell, touch, sight, and sound. Several species make sounds by rubbing their feet together. The sound can be heard up to 20 feet away and lasts less than a second.

Even though their eyes do not move, Wolf Spiders can see in four directions at once.

If a female Wolf Spider’s egg sac falls off, she reattaches it to her spinnerettes. If she cannot find it, she attaches another round object such as a ball of paper.

How does this bug affect people?
Wolf Spiders are helpful to people because they eat insects. California farmers keep them in rice fields to eat insects that harm the crops. Each spider eats between 5 and 15 insects each day.

They do not attack people but may bite if picked up. Their bites are as painful as a bee sting. Some of the most common symptoms from the venom are itching, swelling, and mild pain. People with allergies could develop more severe symptoms.

Wolf Spiders are important because they eat a great number of harmful insects. They are not considered pests themselves, but may wander into houses and frighten people.