General Information

• Size: 1/4-inch
• Color: Ranges from white to nearly black, but most often pale brown

If you’ve spotted a few spider webs in your house, chances are those are the webs of the common house spider. This species has adapted remarkably well to areas and environments that have been occupied and changed by humans. Wherever there are human-made structures, you’re likely to find these spiders. As such, this species and humans have been cohabiting for many centuries, and will likely continue doing so for many more to come.

What Are Common House Spiders?

Some people use the term “house spider” to refer to multiple types of spider species, such as the barn spider or the drain spider. However, the term “common house spider” is most often used in reference to the species parasteatoda tepidariorum, which is also commonly known as the American house spider. This is due to the fact that these are the spiders that Americans encounter most often in their daily lives.

Scientists believe that this species may have originated in South America, which could be a possible reason for their prolific presence in the U.S., including in cities like Austin, Texas; Charlotte, North Carolina; and Chattanooga, Tennessee. However, they have achieved a global distribution — often through shipments of plants — and can be found virtually anywhere in the world today. Although they are related to the notorious black and brown widow spiders, the common house spider is shy and harmless.

What Do Common House Spiders Look Like?

The common house spider has an average body size of 1/4-inch long, with females tending to be larger than the males. Although they can range from white to nearly black, these spiders are often dull brown in color, with some exhibiting brown or white spots on their abdomen. Their size and coloration allow them to effectively blend into their background and escape notice.

Besides their slight difference in size, there are other ways to distinguish between males and females. Adult males typically have a slimmer body type and often walk around. In contrast, adult females have a larger abdomen and tend to linger on the web. In addition, the legs of males have an orange tint, whereas the legs of females have a more yellowish color.

What Are the Habits of Common House Spiders?

The common house spider likes to build its web in the corners and other secluded areas of houses, barns, garages, and other buildings. Some of their favorite spaces include ceilings, doors, window frames and sills, closets, and underneath furniture. Their webs are easily recognizable, as they contain a more densely woven part near the center where the spider typically sits. If the web is in an open space, the common house spider will often place a leaf or two on the web so that it can hide underneath.

As is the case with other cobweb spiders, the common house spider follows disturbances on the web where their prey becomes entangled and then paralyzes them. They typically feed on small insects like flies, ants, mosquitoes. However, they may also at times target larger prey, such as grasshoppers, cockroaches, and even other spiders.

Unlike many other spider species, the female common house spider is not aggressive towards the male and is usually the party that initiates mating. In addition, a male and female often share the same web for prolonged periods. Females are mostly quite tolerant of other females building their webs in close proximity to theirs, which can result in big masses of cobwebs. However, when females encounter each other, they may attack.

A female can mate with several different males or may choose to mate repeatedly with the same partner. This can happen at any time of the year. The female deposits up to 250 eggs into a brown, flask-like sac at a time, and may produce as many as 4,000 eggs in her lifetime. The lifespan of the common house spider is roughly one year.

Do Common House Spiders Pose a Threat?

The common house spider is a synanthropic species, which means they fall into a category in between domesticated and wild animals. Despite the fact that these spiders remain beyond the control of humans, they benefit from living in close proximity to humans. As the species has thrived alongside human geographic expansion, they don’t pose any threat to humans. In fact, they will even allow humans to approach their web.

When threatened, these spiders won’t attack, but will typically drop down a thread and escape from their web. The only time they will bite is in self-defense when they’re physically grabbed or squashed. Although a bite from the common house spider may at times cause some pain, it typically causes no reaction. Those who are sensitive to insect bites may develop a rash or red bumps, in which case a visit to the doctor is advisable.

As the common house spider feeds on common household pests, it plays a big role in controlling pest populations in and around homes and gardens. For this reason, it’s more appropriate to view these spiders as beneficial rather than a potential threat.

How to Control the Presence of Common House Spiders

Apart from the fact that common house spiders aren’t dangerous to people or their pets, they also don’t cause any significant damage to properties. However, if you’re afraid of spiders or don’t like their webs in your house, there are a few steps you can take to prevent them from inhabiting your space. Firstly, you can make it more difficult for them to enter by sealing any cracks or crevices around the house and, generally, covering any potential entry points.

Secondly, aim to get rid of the other insects in your house because spiders feed on them. You can do so by keeping your house as clean as possible, as insects love left-over food and clutter. Remember to regularly wash your dishes, wipe surfaces, sweep the floor, and vacuum carpets. You can, if you wish, inspect their common habitats and physically remove their webs.

However, if you’re experiencing a large infestation or are not sure which spider you’re dealing with, rather contact a licensed pest control company for professional assistance.