With 40,000 known species of spiders worldwide and 3,000 calling North America home, some simple knowledge of spider biology can help you determine which common house spider you have in your home. Read on to learn more about some of the most common house spiders, including which are harmless or potentially dangerous and what they look like.
Meet the Expert
Mohamed Samir is a pest control senior technician with Bugwise Pest Control.
Spiders do not react as strongly to chemical treatments as insects unless they come into direct contact with the spray. Aim to remove spiders, egg sacs, and webs from your house to reduce numbers long-term by using a vacuum, broom, or spider brush with an extendable handle.
Common Types of Spiders Without Poisonous Bites
Common House Spider
Common house spiders, also known as Achaearanea tepidariorum, are just what the name implies: incredibly common. These arachnids are the most regularly seen spiders in all of North America, with sightings ranging from Southern Canada throughout the United States.
If you have noticed dirty cobwebs in the corners of your walls, they could have been left by a common house spider. These dust-covered cobwebs can easily be vacuumed up or swept down without fear of coming in contact with a spider. Common house spiders choose web locations at random and will readily abandon their web to build one elsewhere if their chosen spot does not result in a meal.
Cellar spiders come in two different varieties: short-bodied cellar spiders and long-bodied cellar spiders. They are found throughout Canada and the U.S. and tend to build their webs in dark, moist environments such as cellars, warehouses, barns, and garages, where they spend their days eating insects and other spiders.
Many people mistakenly believe that long-bodied cellar spiders have venom that would be lethal to humans. However, their venom is not potent and they have no ability to pierce human skin with their jaws, making these spiders harmless pest-eaters.
Harvestmen, also known as daddy long-legs, are not technically spiders. They are actually a distant relative of the spider and are frequently confused with the above cellar spider.
When trying to determine if you're dealing with cellar spiders or harvestmen, look at their body shape. Cellar spiders are a yellow color and have two distinct body parts including a long, skinny abdomen. Harvestmen have two body segments as well, but they don't look like it. Their body looks like it has a single, brown or gray oval-shaped segment with eight spindly legs protruding from it. Harvestmen are not venomous and are typically found outside in wooded areas or gardens.
Jumping spiders are hunting spiders that are capable of jumping up to six inches, depending on the species. These spiders commonly wander into homes but can also be carried in on firewood or plants.
Many jumping spiders have red or white markings on their abdomens and can be confused for black widows. Jumping spiders, however, are not dangerous and are actually beneficial, as they enjoy hunting and pouncing on nuisance insects.
Funnel weavers, including the hobo spider, are part of the family Agelenidae and are most noticeable in the fall when their dew-covered webs are visible in the morning hours. Not to be confused with the funnel-web spider of Australia (the only spider in the world that is considered actually aggressive), funnel weavers build their webs in a variety of places including windows, doorways, and cellars.
It was long believed that hobo spiders had a dangerous bite. Reactions vary from person to person, but hobo spiders are not considered toxic to humans, according to the University of California's Pest Management Program.
Wolf spiders are large, hairy hunting spiders that do not construct webs but instead spend their lives running from place to place seeking out food sources. They are frequently confused with tarantulas and are found throughout North America north of Mexico. These are primarily outdoor spiders that hunt nocturnally.
Interior insect monitors are glue traps that can be a valuable tool used to identify and reduce the number of interior hunter spiders in your home. Place them up against the wall or behind dark, damp areas where spiders hide.
Common House Spider Bites
Before getting into house spiders that have venomous bites, it's important to understand that more often than not, spiders are not aggressive and do not bite. "In my experience, the majority of household spiders are harmless and prefer to keep to themselves," says Mohamed Samir, pest control senior technician with Bugwise Pest Control.
Spiders would much rather run away from people as opposed to biting them, and spiders are more likely to bite when they feel threatened.
Don't be too quick to assume that an itchy bump is a spider bite. The Handbook of Pest Control, written by renowned entomologist Arnold Mallis, notes that many insect bites and stings, and even some non-pest-related skin infections, can cause similar skin reactions.
Common Types of Spiders With Venomous Bites
Sac spiders are part of the family Miturgidae and normally found inside (or outside) homes. They use their silk to construct tent-like coverings in low corners. They hide behind these silky structures during the daytime, resting before their nocturnal hunting starts.
Sac spiders vary drastically in coloring and are sometimes confused with other spiders due to shades ranging from yellow to brown to green. It's a good idea to keep your distance from these spiders, as their venom contains cytotoxin and has been shown to be toxic to humans. Use a vacuum or broom to clean them up or hire a local IPM specialist.
What Is Cytotoxin?
Cytotoxin is a toxin that affects the body's cells. The cytotoxin in sac spider venom can cause the bite to be quite painful for an extended period and can cause the wound to heal much slower than usual.
Brown spiders, also known as fiddle-back or violin spiders, are a part of the Sicariidae family. Some are harmless, but this group of spiders also includes the brown recluse, the most dangerous spider of the Loxosceles species.
Identification of brown spiders can be difficult because they all have very similar markings and colorings. If you suspect the spider you're seeing is a brown spider, give it space. Luckily, they are not aggressive and are not likely to bite unless pinned against skin. It is most common for brown recluse bites to happen on the arms, hands, and feet while getting dressed or cleaning storage areas. These bites can often go undetected until hours later when the discomfort sets in.
If you are concerned about brown recluse spiders and live in an area where they are known to be present, take these precautions:
- Shake out any clothing that is left overnight or stays outside (including shoes)
- Make sure there aren't any spiders in your sheets before climbing into bed
- Wear rubber gloves when cleaning out storage spaces or moving firewood
Brown recluse spiders are found most often in the midwestern and southern United States. These spiders are naturally found outdoors in areas where hiding places are readily available, such as debris piles, bark, raked leaves, between or under stones, and within wood piles. These spiders are also well adapted to indoor habitats and will venture into storage areas, closets, attics, and other dark hiding spots.
If you suspect you have been bitten by a brown recluse, ice and elevate the bite while you monitor it. If a bite continues to worsen or you suspect a lesion is forming, consult a doctor for medical care.
Widow spiders are not one of the most common types of house spiders, but are the species most people worry about. If you see a spider in your home, it is likely not a widow spider, but it's still a good idea to know what to look for and how to avoid disrupting them.
Widow spiders range in color, as there are both brown and black widows, but both have a distinct reddish-orange hourglass shape on the underside of their abdomen. There are also false widows, which look similar to a black widow but are completely harmless.
Black widows are widely known for the toxins associated with their bite, but remember that they are very shy. They generally hide in areas that are not commonly accessed and are not likely to bite, as they are not aggressive and rarely leave their webs.
A black widow is most likely to bite after laying eggs and guarding their egg sacs, but only when disturbed. If you need to reach into an area where a spider could be hiding, such as a woodpile or rarely touched storage space, wear rubber gloves to protect yourself from possible spider bites.
According to the CDC, common symptoms of spider bites include, but are not limited to, itching and rash, pain and aching, perspiration, elevated blood pressure, and nausea. If you suspect a venomous spider has bitten you, seek medical attention and do your best to identify the spider.
Removing Common House Spiders
Even though most common house spiders don’t pose a threat to humans, you may not want them sharing your home. If you have an invasion problem, there are plenty of ways to control spiders. Here are a few steps you can take to get rid of house spiders:
- Keep exterior lights turned off, especially overnight. This will reduce insects to feed spiders.
- Regularly sweep the outside of your home. This will help remove spiders, webs, and egg sacs.
- Seal up cracks and crevices around your home. "Spiders love nooks and crannies, so it's crucial to seal cracks, gaps in doors, and windows where they can enter," Samir says.
- Clear clutter to minimize spider hiding spots. Spiders love clutter to build their webs and hide. Minimizing clutter prevents spiders from finding hiding spaces.
- Try peppermint oil. "Natural repellents, like peppermint oil, can be effective deterrents," Samir says.
If you’d rather not fight them on the front lines, you can find a local IPM specialist to help out.
How long do house spiders live?
A common house spider typically has a lifespan of up to one year.
Do spiders typically found in houses bite?
Spiders are actually very shy and do not rush out to attack a person. They usually only bite when they are threatened.
What does a house spider eat?
Most spiders eat other household insects, like flies, ants, and moths. Some even eat other spiders.
What is the most aggressive house spider?
The hobo spider is known to be the most aggressive house spider, but isn't truly aggressive since they will only bite if they feel threatened and are not toxic to humans. Hobo spiders are found in moist, dark areas like a basement.
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