March 31, 2018

Brown recluse spider next to a penny

A Complete Guide to Brown Recluse Spiders

The brown recluse spider gets its name from its reclusive nature, preferring to hide in places where it can live without interruption. It's hard to get rid of brown recluses because of their ability to hide out of sight. When they pick spots that can come into direct contact with people, such as in shoes or blue jeans that have been left on the floor, their new hiding spot can lead to a bite on the foot or calf. Brown recluse spider bites have been the only spider bites I have received that have left a gaping whole in my calf before it healed. Getting rid of brown recluse spiders means finding all of their hiding places. Because they do not build webs out in the open, it's hard to see where this venomous spider has invaded rooms in your home.


What Does a Brown Recluse Look Like?

Brown recluse spider up close

Notice the violin shape on this brown recluse spider.

The first step in getting rid of brown recluses is identifying the spiders on your property. Misidentifying the pests could lead to using the wrong treatment methods and killing nontarget or beneficial insects. Not every brown spider is a brown recluse. In fact, a variety of brown spiders exist across the country and invade homes and businesses every day, such as wolf spiders and cellar spiders. Though other common brown spiders may contain venom, they don't pose as much of a threat as recluses.


How to Identify a Brown Recluse

Brown recluse spiders have soft bodies with a dark brown color; some recluses may appear more tan than brown. Like all arachnids, they have eight legs with fine hairs along each one. Some spiders have spines along their legs. If you see a brown spider with spiny legs, it is not a brown recluse. The legs are also the same color as its body and have no banding, spots or variations in color.

The main thing that separates the brown recluse from other spiders is its eyes. A brown recluse has six eyes, not eight eyes like most spiders have. The eyes are split into three groups with two eyes per group. One group sits at the center of the spider's head while the remaining two groups sit at an angle behind the center eyes.

A brown recluse isn't very large and only measures about a half an inch in length. However, the legs make it appear about 1 inch in diameter. Although the body is solid in color, it does have one very noticeable and identifiable feature: a darker brown mark on its head and back, known more scientifically as the cephalothorax. The mark looks like a violin or a fiddle with the neck pointing toward the rear. The brown recluse is often referred to as the violin spider or the fiddleback spider because of this defined mark.


Where Can You Find Brown Recluse Spiders?

Brown recluse spider on a couch

Depending on where you live, you may or may not ever see a brown recluse spider. These venomous spiders thrive in warmer areas such as the South and the Midwest. They can be found across the United States from Florida to California, and their range extends upward from Texas to Iowa. Though they're more commonly found in warmer climates, they can be found in most any state due to migration and relocation by nesting in transport vehicles.

Brown recluses are highly adaptable and can survive in both hot and cold environments. They will remain active in temperatures as low as 40 degrees and as high as 110 degrees Fahrenheit. These spiders build webs inside cracks, crevices and voids and usually stay out of sight during the day; they prefer to hunt for prey at night.


Common Places to Find Brown Recluses

Brown recluses tend to hide under and around rocks, logs and clutter. They're found in covered objects like wells and utility boxes, including mailboxes and other enclosed spaces. It's possible to find them hiding in thick tree bark and between siding panels on the exteriors of homes, sheds and garages. They'll also nest in, around and between landscape features like rock gardens, flowerbeds and lawn statues.

Though brown recluse spiders tend to stay outdoors, they will often invade interiors through openings around windows, doors and pipes. The gaps around wires also make great entryways for spiders and pests of all kinds to enter homes. When brown recluses come into an interior, they scurry for cover and remain hidden until they feel secure enough to venture away from their hiding spots.

Sometimes they hide in the worst places such as shoes and laundry baskets, where the recluses come into direct contact with people. Some common places to find brown recluse spiders include:

  • Piles of clothes on the floor
  • Pant pockets
  • Stored towels
  • Toolboxes
  • Crawlspaces
  • Closets
  • Fireplaces
  • Dresser drawers

 

How to Avoid Brown Recluse Spiders

Brown recluse spider in a kitchen sink

This brown recluse spider is in a kitchen sink. (Image by Lisa Zins)

No matter if you're indoors or outdoors, it's important to take precaution when reaching for something near the ground, in a void or inside an enclosed space. Thinking before acting will go a long way to keep you safe from brown recluse bites.

  • Wear gloves while gardening and when handling mulch and firewood.
  • Seal cracks and crevices to take away their entryways into your home.
  • Clean out the clutter in sheds, attics, basements and garages.
  • Move stacked firewood away from the foundation.
  • Knock your shoes against the floor to flush out any spiders.
  • Minimize outdoor lighting to reduce pests that could attract recluses.
  • Prevent bedding from touching the floor.
  • Use sticky traps where the spiders may travel or hide.

 

Are Brown Recluses Venomous?

Every spider on the planet has fangs, and all but two spider families have venom. It is rare to come across a spider in the wild or in and around your home that does not produce venom. Brown recluses have fangs and venom glands and inject poison into their prey with a single bite. They're in the top 1 percent of spiders that contain a toxic venom that causes harm to people.

However, the venom doesn't affect everyone in the same way. Some people may only develop a small bump in the bite area whereas others develop an open sore. A brown recluse's venom contains an enzyme that breaks through cell walls and causes a lesion at the wound site. The lesion can range in size from a small circle to something as large as your hand.

In most cases, the open sore will heal on its own within six to eight weeks. However, a secondary infection may occur if the sore isn't wrapped and treated properly. It's wise to seek medical attention if you believe that you've been bitten by a brown recluse. It's extremely rare to die from a brown recluse bite, but it's always better to be safe and to visit a doctor for proper treatment.


How Long Do Brown Recluse Spiders Live?

Brown recluse spider on a wall

Brown recluses are more active in the summer months when warmer temperatures bring out numerous insects for the spiders to feed on; they also mate during this time. Females lay up to 50 eggs in a clutch and will lay as many as 300 eggs in their lifetime. The eggs are encased in a silken sac within the recluse's web, and the young will hatch between three and four weeks later. The young look similar to immature black widow spiders and won't reach maturity for 10 to 12 months.

Brown recluse spiders live for one to two years depending on several factors such as being in the right climate, having access to food and living in a secured shelter. The spiders may live less than a year if the conditions aren't right for their growth and development. Brown recluses with luck and good health on their side may live for three years as adults.

A brown recluse needs food to sustain its longevity, but it doesn't capture prey in a web. Instead, it leaves its hiding spot at night to hunt down various insects. Like any spider, a recluse needs food to survive. However, it can live up to 10 months without food or water. Some studies have found that recluses have a preference for dead prey and can survive without food or water in an airtight container for six months.


Spider Control: Getting Rid of Brown Recluses

Because females lay as many as 300 eggs in their lifetime, it's easy to see how an infestation can quickly come out of nowhere and become a real problem. These spiders are venomous and can cause open wounds in their victims.

Treating a recluse infestation comes down to three things: inspection, elimination and prevention. Without a proper inspection, you might not detect all the brown recluses that are in your home or on your property. Eliminating the infestation is great but not if you've failed to prevent a reinfestation down the road. These three things combined will help to remove the spiders and keep them from posing a threat in the future.


Inspecting for Brown Recluses

Brown recluses nest in places where they can remain hidden from people and predators. Before you start reaching into dark crevices, put on a pair of gloves to protect yourself from potential bites not only from spiders but also from stinging and biting insects. You should also wear pants and a long-sleeved shirt to protect exposed skin from bites as you crawl or lie on the ground.

Inspect in and around your home where you've seen the recluses or suspect them to be hiding. A thorough inspection is the key to treating the pests and ensuring complete elimination of the entire infestation inside and outside of your home.

  • Check for recluses in piles of lumber and firewood. The spiders may also lurk beneath garden stones or paving stones leading to the front porch.
  • Inspect the ivy and vines that have grown along the foundation or on nearby trees and shrubs.
  • Look in wall voids and crawlspaces, making sure to use a flashlight for spotting the recluses hiding deep within the area.
  • Sift through clutter in the basement and the attic, including any piles of clutter in the yard. Clutter provides the perfect shelter for brown recluses.

Treating Brown Recluses

Onslaught Brown Recluse Spider Insecticide

Onslaught FastCap Spider Insecticide is one of many popular products.

You can treat a recluse infestation in many ways. For one, insecticide sprays and dusts work wonders for killing the spiders on the spot and preventing a reinfestation. Insect monitors and traps also help and provide both a nonchemical and preventative solution to combat the problem.

  • Insecticide Dust: Because brown recluses often hide in cracks and crevices, it's good to use a dust that reaches into and covers their hiding spots. Dusts usually contain pyrethrins and synthetic pyrethroids for quick and residual kills. Some recommended dusts to use include:
  • Contact Aerosol Spray: A contact spray comes in the form of an aerosol and provides an easy way to treat recluses on the spot. They offer quick knockdown but don't provide any residual effects. We recommend the following aerosol insecticides:
  • Insect Monitors and Traps: Sometimes you're unable to use spray insecticides indoors or outdoors. In those cases, using insect monitors and traps helps to eliminate the spiders without spraying the area with chemicals. Most traps contain food-grade substances that lure the pests from their hiding spots. Though spiders aren't attracted to the bait, they will attempt to cross over it and become stuck on contact. Monitors also have sticky interiors and give you a way to monitor an infestation in the target area. Our recommendations for traps and monitors include:

Preventing Brown Recluse Infestations

It's important to take preventative action if you want to keep recluses from invading your home and property. Though you can perform this step after treatment, it's a good idea to take preventative steps beforehand to make the treatment process more effective.

  • Remove all debris from around the foundation, including stacks of firewood, plywood and other large materials. Removing these obstructions will not only take away the spiders' shelter but also keep them away from the house.
  • Use a vacuum to suck up the spiders and their egg sacs from inside wall voids and cracks and crevices. If you vacuum beforehand, do it again after treatment to remove any survivors.
  • Seal cracks and crevices with a silicone or foam sealant inside and outside of your home. Make sure to seal the spaces around windows and doors, vents, pipes, wires and other areas where recluses could enter from the outside.
  • Perform a once-over in the treated areas, making sure to look inside boxes and under furniture for any remaining spiders. If you find any brown recluses, kill them on the spot with an aerosol spray. You may have to retreat the entire area for added assurance.
  • Set up insect monitors and traps in high-risk areas after using an aerosol or a liquid insecticide. The traps will continue to capture spiders and other insects and prevent an infestation.

Brown Recluse Spider

Brown recluses have a reclusive nature and may be lurking out of sight, making it hard to get rid of them. They come out at night to hunt for prey and prefer to nest in dark places. If you have another pest infestation in your home, it could lure the spiders and provide enough food for several generations. Recluses can live for up to three years as adults indoors where the conditions are right for their survival. By inspecting for these pests and using proper elimination methods, including taking preventative action, you can keep brown recluses out of your home and protect your family from venomous bites


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