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Brown Recluse Spider Identification and Control
Accurate brown recluse spider identification is important because these spiders (Loxosceles reclusa) possess a bite that can be a serious threat to humans. They are common and widespread, especially in the South, so it's possible that you may have these spiders living in your basement. Global warming has increased the brown recluse's range to the point where it may be found anywhere in the lower 48 states. The bite is initially painless, but in some cases, the venom triggers a necrotizing process that may destroy large amounts of tissue. The bite is rarely fatal but it may result in permanent scarring.
Controlling brown recluse spiders safely is not difficult—read more to learn about these spiders and how to control them.
How to Identify Brown Recluse Spiders: Size and Markings
Look closely at the back of this spider—can you see the dark violin? That's the tell-tale brown recluse identification mark. Adult brown recluse spiders have a distinct violin-shaped mark on their back, a feature that other spiders in your home don't have. Accurate brown recluse identification begins with this unique marking and includes other factors like size and color. Many other spiders are the same size and color as the brown recluse, but none of the ones around your house will have the clear, sharp violin mark.
What To Do If You Have Brown Recluses in Your House
First of all, don't panic! You may have many of these spiders in your house and never see one or suffer a bite. In 2001, more than 2,000 brown recluse spiders were removed from a heavily infested home in Kansas, but no one in the home ever even knew they were there or had been bitten—as far as they knew. Brown recluses have short fangs and would rather run than fight. They live in dark corners and come out only at night.
One good solution to a brown recluse infestation is to put out sticky traps. These traps are non-toxic and highly effective.
Sticky Traps for Brown Recluse Spider Control
In my experience, the best thing about spider sticky traps is that they contain no toxins or poisons. They are simply cardboard coated with sticky stuff and in some cases an attractant. Sticky traps also catch other insects, both good and bad, so only use them if you have a real, documented brown recluse spider infestation.
This map shows the general range of spiders of the Loxosceles genus in North America—but due to climate change, the brown recluse range is expanding to the north. Spiders are now found commonly as far north as Chicago and beyond. This is true, by the way, for many other animals and insects, some of which you may wish would stay put where they are. Bed bugs, for example, are just one of the many little critters heading your way!
This illustration shows some basic differences between an insect, like a bed bug, and arachnids, like the brown recluse spider.
(1) The bed bug has antennae, which are sensory organs that help the insect find food and avoid predators. They are often much more useful than eyes to the insect. The spider, on the other hand, relies largely on eyesight—they have as many as four pairs of eyes, and use them! It's very hard to sneak up on a spider.
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(2) Insects have three sections: head, thorax, and abdomen, while the spider has two segments; the head and thorax are combined into the "cephalothorax."
(3) The Insect has reproductive organs in the tip of the abdomen. The spider does too, but in addition, it has a pair of "spinnerets," organs that spin silk. This process is worthy of a book in itself—turning liquid into tough silk to catch prey, and then "eating" the web to recycle the material for a future web. Amazing!
Not every spider is a brown recluse, so please don't go around killing every brown spider you can find! Learn to identify brown recluse spiders and you'll know
Most brown recluse bites do not result in the large, necrotic wounds that will find all over the internet—those are the worst-case scenarios! Still, it does happen, and this bite is one of the less-disturbing examples. The venom destroys living tissue over the course of several weeks, and when the damage finally stops you may be left with a disfiguring scar. Take these bites seriously! If you think you may have a brown recluse bite, GO SEE A DOCTOR. In some cases, infections can be fatal.
What to Do If You're Bitten by a Brown Recluse Spider
You're bitten by a brown recluse—what do you do? Freak out? Panic? Run around the room?
Probably not, because you won't even know you've been bitten. The bite of the brown recluse, unlike those of other venomous animals, is typically painless. The fangs are small, and you are not likely to notice the bite at all. Brown recluse spiders often roam around at night looking for prey and can get tangled up in clothes left on the floor, which can result in a bite.
The fact that the bite isn't usually painful is good news and bad news. On one hand, it doesn't hurt, and you can go about your day pain-free. Most bites don't result in a problematic wound, so you may not know you've been bitten at all. The bad news is that for those bites that do get bad, you may not connect the wound to a spider bite, especially if you never felt the bite or noticed the spider.
Recent studies have shown that the majority of brown recluse bites never develop into a serious or even noticeable situation, but simply fade away as the venom gets eliminated from your body. In addition, some terrible-looking bites, with huge wounds that don't seem to heal, may really be due to other causes, such as diabetes or staph infections. That may be cold comfort for you if you're dealing with a serious wound, but from the spider's point of view, it's highly relevant: don't blame these little guys for every bad situation!
But if you have made an accurate brown recluse identification and you know you have been bitten, get an ice pack on it to slow the spread of venom. Keep the spider to show the doctors so they too can identify it as a brown recluse, and head straight to the emergency room!
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
James on March 12, 2020:
I have them and caught them on glue traps how do u know when u dont have them any more
email@example.com on October 13, 2019:
Though I have not seen one I will do whatever it takes to make sure it stays that way.