At present, there are about 40,000 species of spiders around the world that have been officially named. Of these, 3,000 species call the United States home. Despite how most people feel about spiders, they serve an extremely valuable purpose. Without spiders, the populations of certain insects would likely become overwhelming. In addition, many species of spiders become food for other animals.

Important Note on Poisonous Spiders

While most of the 3,000 species of spiders found in the United States are not poisonous, this does not mean that they are harmless. According to entomologist Rick Vetter of the University of California, Riverside, most spiders are helpful to humans and the environment and don’t cause harm.

While nearly all types of spiders have venom, only a few species have venom deadly enough to be of consequence to humans.

The yellow sac spider builds nests of silken tubes under stones, or in grass or leaves. A small spider often measuring only about 0.6 of an inch or less, its venom is made up of a substance that can impair the functionality of your body’s cells or even destroy them completely. Unlike some other spiders, this species is not particularly docile. Often found inside homes and other structures, female yellow sac spiders have been known to bite as a defense mechanism while protecting her eggs.

Though this spider’s cousin, the black widow spider, receives a great deal more press, the venom of the brown widow spider is thought to be twice as powerful. The brown widow is thought to be a native of Africa though the first specimen was identified in South America. It is considered to be an invasive species and can be found in the Gulf Coast states as well as southern California.

The appearance of the brown widow spider can vary significantly from one specimen to the next. Its body can be tan to almost black. Their abdomens sport ornate markings of white, yellow, brown, orange or black, with an orange hourglass marking. Though the brown widow spider is not aggressive and injects only a small amount of venom when it bites, it has been linked to at least two deaths.

Wolf spiders comprise a large group that boasts about 125 species found throughout the United States. The largest of these has a body about an inch in length with legs that are similar in size.

These dark, hairy arachnids are often found outdoors, where they build tubular nests lined with silk under leaf litter, stones or logs and in the grass. Known for their running speed, wolf spiders can be found inside homes, especially if they have an insect population that entices them. They are not considered to be aggressive and generally only bites in self-defense. Although venomous, most people will experience only noticeable trauma at the bite site due to its fangs. However, allergic reactions have resulted in dizziness, nausea and elevated heart rates.

The brown recluse spider is considered to be one of the most dangerous spiders in the country. Only about 0.25 inches in length with one-inch legs, its venom destroys the blood vessel walls near the location of the bite. This can sometimes result in a large skin ulcer which can take months to heal and become infected. In rare cases, these infections can be fatal.

can measure about half an inch in body length, with legs that span as long as two inches. This brown arachnid’s bite is often so painless that it is often initially overlooked. But after about 24 hours, this wound begins to blister. Within 36 hours, the blister disintegrates and leaves a gaping and oozing sore. Other symptoms of a hobo spider bite are weakness, temporary memory loss, nausea, fatigue, and vision impairment. The hobo’s habitat of this spider is primarily within the states of Wyoming, Idaho, Utah, Oregon, Montana, Colorado and Washington.

Prevent Spider Bites

Preventing spider bites means being aware of their presence. For example, The pale sac spider causes the most spider bites.. Though these spiders are numerous and aggressive – and they are often found inside your home – their venom is not considered to be very dangerous or toxic to people.

Indoors, make sure that you clear away spiders and cobwebs on a regular basis. Keep your floors clear of boxes where spiders might hide or keep them taped closed. Keep clutter to a minimum in your  basement, garage and attic.

Outside, it is important to wear long sleeves, long pants and gloves if you will be in the areas where spiders like to hide. Watch where you are putting your hands when you are raking leaves, clearing debris, or moving wood from a woodpile.

Keep trees, leaves and other clutter away from the sides of your home. Look for, and seal off, any holes, gaps and cracks that spiders might be able to use to get inside your home.

Treatment of Spider Bites

The treatment of a spider bite depends on the species. In most cases, washing the site of the bite with soap and water will be necessary. You might experience some redness and swelling in this area.

You will probably feel a slight pinprick at the time of a black widow spider bite. But within a few hours, you will notice muscle cramps, stiffness, fever, abdominal pain, vomiting and other symptoms. If you are bitten by a brown recluse spider, there will be stinging and redness at the site. Later, the area will blister before becoming an ulcer. Both of these spider bites warrant further care than that which can be rendered at home. After washing the area with mild soap and water, apply a cool and damp cloth to it. If the bite is on a limb, keep it elevated before seeking out medical attention.

Keeping Spiders Away

Given the sheer number of spider species in the United States, keeping them away means a concerted effort of cleaning and removal. Try to maintain a regular schedule of mopping, sweeping and vacuuming inside. Remove spider webs from ceilings and walls often.

Outdoors, keep leaves raked and situate wood stacks well away from your home. Mow the lawn on a regular basis and trim trees and bushes often to prevent a way of entry for spiders.

Top Tips for Spider Control

Traps allowing you to catch and release harmless spiders outside can help you control the occasional spider. Cleaning your exterior doors and shaking off your clothing before entering your house can reduce the introduction of outdoor spiders into your interior.

Spider Infestations: When to Call the Professionals

Spiders are often found near their source of food.  If you have an insect problem inside your home – such as ants in the spring – chances are that you will also start finding more spiders as well.

Some types of spiders like to live in moist or damp environments. These include places like your basement, shed or garage.

If spiders continue to appear in the corners of your home no matter how often you sweep the areas down, you most likely have an infestation. It is during these times when the typical strategies of increasing the home cleaning routine and trapping them aren’t working that you should call in the professionals to deal with it.