The Real Reason Your House Has Spiders (and How To Get Rid of Them)

Despite the fake cobwebs and fun, sparkly spiders people love to put up every Halloween, no one seems to like the real thing. Plastic arachnids might bring a smile, but barely glimpsed, eight-legged critters scurrying across your bedsheets evoke entirely different emotions—from annoyance to existential terror.

We get it! But while many people are afraid of spiders, the creepy critters are usually a benign presence in your home, and one of the easier pests to get rid of.

We spoke to spider and pest experts to get all the details on why these insects enter our homes and how to eliminate them. Here’s everything you need to know to make your house spider-free (except for decorative purposes) this season.

Why does my house have spiders?

If you’re one of those people who have true arachnophobia, you might want to stop reading now— because you’re definitely not going to like what entomologist Nancy Troyano, of Ehrlich Pest Control, has to say.

“Only 5% of the spiders you see inside have been outside,” she says. “Most of the spiders you see around your house have probably been living there for a while.”

They also tend to come out of their hiding places in fall and spring to mate. So if you’re suddenly seeing more spiders in your home, it doesn’t mean they’ve invaded. You’re just finally becoming aware of them.

As for what keeps these unwanted housemates hanging around, it’s simple enough: food. And in the case of spiders, that means other bugs. So having them around can actually control the numbers of other insects in your home.

“Spiders will always prefer making a home in a quiet and calm environment where they can live undisturbed, and have access to food and warmth,” says Natalie Barrett of Nifty Pest Control. “They also feel safer in cluttered spaces. In homes, their most preferred areas include garages, basements, storage rooms, and attics.”

Besides cozy clutter and an ample supply of bugs, spiders are also attracted to warm and humid environments, like bathrooms.

cluttered attic
Spiders love cluttered spaces like this attic.

c_taylor/iStock

The good news about indoor spiders

There’s good news for spider haters—sort of. Despite how repellent they may look, most indoor spiders won’t actually hurt you.

“The vast majority of common house spiders rarely, if ever, bite people,” says Ed Spicer, CEO of Pest Strategies. “Out of the 40,000 spider species on Earth, about 12 can hurt you.”

In fact, in the U.S. there’s really only two types you need to worry about: the brown recluse (brown with a fat body and skinny legs) and the black widow (black with a distinctive red hourglass mark on its back).

“Black widow and brown recluse bites are rarely lethal to humans,” says Spicer, “but they could very well require medical attention.”

How to get rid of spiders

While spiders are apparently a benevolent force in your home, keeping the bug population under control, the reality is that most of us don’t want them around.

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Ask Dr. Universe: Why do garden spiders hang upside down in the middle of their webs?

Washington State University

Dear Dr. Universe: Why do garden spiders hang upside down in the middle of their webs? – Abree, 10, New Jersey

Dear Abree,

That’s a great observation. Garden spiders and other orb-weaver spiders crawl all around their webs, but we often see their heads pointing down toward the ground.

My friend Todd Murray, an entomologist at Washington State University, told me about a group of scientists who had a question a lot like the one you’ve asked.

These scientists used mathematical models to learn about orb-weaver spiders and how they move around the web. They discovered spiders that wait with their head down for prey can reach prey faster than spiders that wait with their head up for their prey.

While there are exceptions, this position gives spiders an advantage when getting food. Sometimes, prey will hit the top of the web but end up tumbling to the bottom of the web. A spider higher up on the web with its head facing down would be able to see prey below. Gravity also helps spiders as they run down the web.

Murray reminded me how different kinds of spiders can make different webs. Orb weavers tend to make webs in circle shapes. These spiders have parts called spinnerets located in their rear ends, or abdomens, that produce the silk.

Some orb-weavers might create a trap line with their silk, which attaches them to the middle of the web. When an insect hits the web, the trap line vibrates, and the spider can sense dinner has arrived. It might just be a fly, mosquito, moth or wasp.

As fall gets underway, orb weavers eat lots of insects and get bigger. You might identify an orb weaver from its brick red to orange body with white splotches. We see quite a few orb weavers in Western Washington at this time of year. You might notice more spiders and webs in your neighborhood, too.

We are still learning exactly why some spiders build certain kinds of webs. Murray said a wasp in Costa Rica has even revealed how a spider’s web designs can get hacked. The wasp glues an egg on the spider’s abdomen. When the egg hatches, the little larva attaches to the abdomen and starts living off the spider.

“That grub sits there and steals the nutrients from the spider like a vampire does, or a tick, or other blood-sucking creature,” Murray said. “As that grub grows on the spider, the spider does a really amazing thing.”

On the last night of its life, the spider start building a totally new kind of web that looks a bit like a hammock. Once the hammock is made, the spider puts the larvae into the hammock.

“It really does show you how those web-building abilities are hard-wired in the spiders and that they can be manipulated,” he said.

If you keep asking great questions like scientists do, maybe you’ll help us learn even more about the world of arachnids. In

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