Sneaky Spiders: The 2 Most Venomous Spiders In The U.S.

Spiders are interesting pests. They don’t invade in large numbers, cause structural damage, or eat our food, which is more than we can say for most pests. Spiders do hide in dark corners, produce hundreds of eggs at once, and weave their sticky webs around our furniture and lights, so they still aren’t fun to have around.

Most species want nothing to do with us and will run away instead of staying to bite. However, there are two types of spiders in the U.S. that will immediately unleash their venomous bites when someone gets too close to their shelter. The black widow and brown recluse are both found in the Midwest, so let’s discuss the basic facts about these arachnids before diving into the most efficient ways to prevent spiders from invading your home.

The Black Widow

In addition to being the code name for a famous superhero, the black widow is one of the most well-known spiders in existence. It prefers to stay hidden in the shadows, especially under larger objects. The black widow needs to stay dry and sheltered as much as possible, which is why they invade isolated corners of garages, sheds, barns, and meter boxes.
This spider has an unmistakable appearance because of its distinct features, including:

  • Jet black coloring
  • Red or red-orange hourglass marking
  • About 3/4 of an inch long (females) or 3/8 of an inch long (males)
  • Messy-looking webs

Black widows seclude themselves to hidden spaces, especially when the female is ready to produce her egg sac. This silk-encased vessel contains hundreds of eggs that are safely hidden in the sac until they are ready to hatch. Once they’re ready, the hatchlings stay close to their mother and eventually produce enough webbing to balloon away on a nice wind current. The adults also rely on currents and vibrations to sense everything around them; females perch on their webs to feel for vibrations from incoming insects.

Speaking of their webs, black widows will only bite when they feel threatened because their home is directly disturbed. For instance, a person who unknowingly reaches underneath a shrub and touches the black widow’s web will likely receive a bite. The spider’s venom has a neurotoxin that can compromise a person’s immune system if it goes untreated.

The good news is that black widow bites are rarely fatal anymore because of modern medicine. Plus, the amount of venom they inject is adjacent with the spider’s small size, so it’s not a huge amount. A bitten human will still experience different symptoms over the following hours until they receive treatment. Some of the most common ones are fever, vomiting, trouble breathing, muscle cramps, and flu-like symptoms.

The Brown Recluse

This spider shares quite a few similarities with the black widow. Brown recluses also prefer to stay isolated, dry, and warm. They are common in the Midwest and Southeast, and tend to hide in dark places that offer them shelter from the elements. Their favorite hiding places are inside closets, boxes, wood piles, stones, and utility boxes.

The brown recluse, also called the fiddleback spider, has distinct characteristics including:

  • Tan or dark brown coloring
  • Fiddle-shaped marking on their cephalothorax (hence the nickname)
  • Up to 1/2 an inch long
  • 6 eyes in a semicircle pattern
  • Loose, irregular webs

As opposed to black widows, brown recluses don’t use their webs as their primary way to catch prey. These spiders prefer to hunt for their food and dine in peace near their web. When the female produces her egg sac, she will either stick it to the web or the ground in a secluded area. Once the eggs hatch about a month later, they scatter to find their own shelters in new areas.

Brown recluses have a strong bite that has a severe effect on their victims. When it comes to their food sources, these spiders adapt to whatever comes their way. They can incapacitate small prey that’s still alive, or feed on larger prey that is already dead. As for humans, brown recluses only bite us to defend themselves when they are touched or feel threatened.

A brown recluse bite is also completely treatable, but the road to get there isn’t very fun. Their venom is potent and causes the bite to take weeks to heal. The pain is often delayed after the incident, so a bitten person may not experience pain at first. The bite will eventually grow into an open ulcer over the following weeks. This spider’s bite also causes other symptoms, including muscle cramps, fever, and an allergic reaction.

If you or anyone in your home is bitten by a black widow or brown recluse, please seek medical attention immediately. These bites are easily treated with instant care and proper medicine.

How to Prevent Spiders

The main spider fact to remember is that they only live where they have a steady food source. In other words, where there are spiders, other pests are sure to be found. Spiders provide us with a small amount of natural pest control by feasting on their prey. However, it’s still not ideal to have a spider — or worse, all of their offspring — in the house, so it’s best to prevent any type of pest from invading in the first place.

The most efficient ways to prevent spiders from entering your home are to:

1. Seal Entry Points.

Spiders are small enough to slip through tiny gaps in the exterior. Seal smaller cracks and gaps with caulk, and fill larger holes with steel wool before lining with caulk.

2. Fix Window Screens.

There’s nothing like opening the house up on a nice day, but holes in the window screens will let in all kinds of pests. Patch smaller holes with extra screen material; if a window screen is full of gaps, replace the whole screen with new mesh.

3. Trim The Greenery.

If any tree branches or bushes touch the house, they act as natural freeways for spiders to travel into your home. Trim back every plant, bush, and tree at least one foot from the house on a regular basis.

4. Clear Clutter.

Spiders love hiding within clutter, especially black widows and brown recluses. The areas that tend to collect clutter (garage, basement, attic, shed) are also usually darker and more isolated, which appeals to spiders even more. Keep any stored belongings in plastic bins rather than cardboard boxes, and try to arrange them as neatly as possible.

5. Replace Door & Window Seals.

The weatherproof seals around doors and windows naturally wear down over time, especially if the region experiences a lot of intense weather. If you notice a seal peeling away from the house, replace it with a new one as soon as possible.

6. Solve Pest Issues.

Finally, the best way to prevent spiders from invading your home is to simply eliminate their food source. An insect infestation — whether large or small — needs to be solved before hungry spiders find it. Store-bought products and DIY treatments can’t get to the root of the problem, which is why pest control is best left to the professionals at Reliable Pest Solutions!

Rely On Reliable’s Spider Control Services

One spider may not seem like a big deal, but this pest causes further problems once it feels safe enough to produce an egg sac full of tiny spider eggs. The most efficient way to keep a home or business spider-free is with professional services, so your local experts at Reliable Pest Solutions are here to help! We solve each pest issue with the utmost care because we truly value the needs of our wonderful clients. From termites to spiders, we tackle any pest problem that Illinois, Iowa, and Missouri have to offer. Contact us today to learn more about our effective treatments and why you can always depend on Reliable’s services.


Black widow spiders. (n.d.). Pest World. Retrieved February 9, 2024, from
Brown recluse spiders. (n.d.). Pest World. Retrieved February 9, 2024, from
Spiders. (n.d.). Romney Pest Control. Retrieved February 9, 2024, from

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