Brown Recluse Spiders in Illinois: Where They Live, What They Eat, How to Get Rid of Them

Brown recluse spiders (Loxosceles reclusa) give a nasty nip, and they have a secretive habit of hiding beneath picture frames, but are they dangerous? This article will discover brown recluse spiders in Illinois, where they’re found in homes, and how it’s possible to get rid of an infestation.  

The critical thing to remember is that brown recluse spiders rarely bite humans, and there are just a handful of cases linked to death.

Key Points

• Brown recluse spiders’ timid habits mean you may be living with them but never notice.
• They’re easy to recognize by the violin-shaped marking on their cephalothorax.
• Brown recluse spiders build small, dense webs in room corners but hunt by stalking their prey.

Do Brown Recluse Spiders Live in Illinois?

Yes, brown recluse spiders live in Illinois, U.S. They chiefly reside in the southeastern quarter of the United States, as far north as southern Illinois.

Outside this range, it’s very rare to spot a brown recluse spider. Many reports are simply misidentified.

Brown Recluse Spider: Species Overview

Appearance

Brown recluse spiders in Illinois are medium-sized spiders with small bodies and long legs. When outstretched, these shy guys measure no wider than a quarter. No surprise that brown recluse spiders appear brown, but on occasion, black-gray and white shades appear too.

The easiest way to identify a brown recluse spider is its lack of any markings except a distinct violin-shaped mark on its cephalothorax (the portion of the body to which the legs attach). Due to this distinctive mark, they’re known as “violin fiddle back spiders” or “brown fiddlers.”

The older the spider, the darker its markings! Elderly brown recluses’ violin marks mature to jet black. Did you know brown recluse spiders have only six eyes instead of the usual spider arrangement of eight? Their eyes are set in three pairs, but experts don’t know why.

Venom

Loxosceles reclusa spiders sit in the Sirariidae family, and they have pretty potent venom. Experts say their necrotic venom is stronger than rattlesnake venom, but because a brown recluse injects so little into humans, deaths are almost unheard of. However, a brown recluse spider bite is likely to leave an itchy, stinging lump. It’s important to clean the wound.

Only three North American species have toxic venom. The other two are the black widow and the Chilean recluse.

Hunting

Brown recluse spiders are hunting spiders that roam at night in search of tasty insect prey. The female’s web is a safety retreat, not a device to catch insects. These quiet stalking masters hide, then pounce on their unfortunate passing prey. Brown recluse venom is fast-working and incapacitates its victim within seconds.

Life Span

Long-lived and so tough they can go without food for months, brown recluse spiders are the spider world’s survivalists. Amazingly, a female brown recluse only needs to mate once. This is enough to fertilize eggs across her entire lifetime.

This incredible mating habit is one of the reasons why brown recluse spiders easily start up an infestation, along with their superb hiding skills, of course.

Diet

Opportunistic hunters, brown recluse spiders grab, paralyze and ingest prey, but recent studies indicate they scavenge too and may even prefer to scavenge recently dead animals instead of killing fresh prey.

Here’s a list of the creatures brown recluse spiders eat.

• Crickets
• Cockroaches
• Moths
• Flies
• Grasshoppers
• Mayflies
• Dead insects
• Other spiders, including their own kind. Yes, cannibalistic brown recluse spiders prey on one another.

Predators

Birds like blue jays, praying mantis, spider wasps, centipedes, and other spiders, such as the incredible wolf spider all prey on brown recluses. It’s no wonder they prefer to live in your home.

Are Brown Recluse Spiders Dangerous?

It depends.

Their bite sometimes needs medical attention. Their necrotic venom can badly affect children, older folks, or anyone who’s unwell.

If bitten, you should clean the wound with soap and treat it with an ice pack or cold running water. Try elevating the wound if it’s throbbing. These bites are known to burn and hurt for hours. Often, a small scar will build and take months to heal up. In general, brown recluse spider bites pose the most threat if they become infected.  

That said, brown recluse spiders hardly ever bite humans, and if they do, it’s because they’re scared or hurt. They do not hunt humans or pets (unless your pet is a grasshopper) but try to keep as far away as possible.

Where Do They Live in Illinois?

Illinois is home to over 500 spider species, but only two pose a problem. That’s the brown recluse we’re looking at today and the black widow.

Brown recluse spiders live in the southeastern and central U.S. regions — usually south of the Great Lakes and above the Gulf of Mexico. However, they do sometimes hitch a lift in cargo, so they’re not totally unknown in other regions.

Southern Illinois is warm enough to host brown recluse spiders, but they’re rarely found in the north. This research paper indicates that the brown recluse lives inside and outside in the southernmost third of Illinois, indoors only in the second third, and rarely found in the top third. This leads experts to conclude that brown recluse spiders can’t tolerate temperatures below -5 degrees centigrade over the winter months.

Inside Your House

There’s a reason why you’ll barely spot brown recluse spiders, and the clue’s in their name. They’re reclusive! These furtive spiders are not fans of socializing but rest during the day in hidden locations. Top des-res spots for brown recluse spiders in a home include:

• Covered wooden surfaces
• Paper
• Under wall-hanging picture frames
• Inside the furniture, e.g., in the sofa springs
• Cardboard boxes
• Wall voids
• Wood framing of crawl spaces
• Basements
• Attics
• Any storage box that’s rarely used
• Dark and undisturbed places

Experts say brown recluse spiders in Illinois can go without food for ten months. That’s incredible and explains why they’re so good at surviving in barren spaces.

Outside Your House

In the great outdoors, brown recluse spiders take advantage of hiding places such as fallen logs, rocks, and discarded furniture.

Even though research suggests they are not found outside in the top third of Illinois, it’s always important to keep your eyes peeled and wear thick gloves when handling potential brown recluse hiding materials, e.g., a wood pile or summer deck furniture.

How to Get Rid of Them

Brown recluse spiders worry householders. They are one of the two spiders in North America that bite humans and are also excellent at hiding.

If you have children, elderly, or immune-suppressed folk in the home, potential brown recluse spiders become more of a problem.

One of the best actions is making the home spider-proof. It’s not 100% effective, but it can prevent many unwanted critters from entering your property. Once a mated female enters your home, she’ll lay eggs, which means trouble. Getting rid of this spider is difficult once it’s established indoors.

So, to keep them out, try and do the following.

The photo featured at the top of this post is © iStock.com/Wirestock

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