In case you haven’t gathered as much, I’m a sucker for spiders. I always have been. When I was a kid, I would catch them around the house and keep them in Mason jars with holes in the lid so I could feed them and watch them eat. It was fascinating! At the time, I never really noticed that every spider I found looked the same. It wasn’t until way later that it all came together...

They Were Brown Recluses

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Loxosceles reclusa

The brown recluse is one of just a hand full of spiders in North America known to be dangerous to humans and one of only two native to my home state of Arkansas. In fact, Arkansas seems to be right in the center of the brown recluse’s area of distribution, as they are found within about a 2000 km radius of the center of Arkansas. The name says a lot about this species: they are predominately brown in color, and they tend to stay hidden in dark, dry places. In nature, they are normally found in crevices under rocks, tree bark, or other detritus. However, the recluse spider has adapted extremely well to human interference. They are more than happy to make their home in a storage shed or even your home! They are often found in clothes that have been left undisturbed for a while, and they have a particular affinity for cardboard. Really, anywhere that they can find a dark space is fair game.

Diet & Web

Like almost all spiders, the brown recluse preys largely on insects and even other spiders. They are active hunters and have even been known to feed on recently killed insects, so they do not use their web spinning abilities to build any sort of trap for their prey. Instead, they dense, irregular retreat webs in out of site places. The silk that they spin is unlike that of any other spider studied so far. Their flat spinnerets produce a flat ribbon-like silk that is 20 times thinner than that of most other spiders without compromising strength. Tests show that it can be stretched up to 30% longer than its original length.

Identification

Range

The range of the brown recluse is really quite limited. While people all over the U.S. often claim to see them, many of these sightings are misidentifications. Even extermination professionals get it wrong, and medical professionals misdiagnose a wide range of skin maladies as brown recluse bites. Their habitable range is restricted to the southeastern and portions of the midwestern US. Rick Vetter, retired entomologist from the University of California, Riverside reports that he has received around 500 specimen sent in for identification from areas within the known habitable range of the spider. Of those, about 75% turned out to be brown recluse spiders. On the other hand, he has scoured California looking for a correctly identified brown recluse, polling exterminators, arachnologists, and other enemologists. His search has spanned multiple decades and examined some 20,000 reports, but has turned up exactly zero positive recluse identifications. In fact, he has only found records of 15 verified specimen found in the state over a 40 year period. Most of those were probably brought in by people relocating from the south. But still, 15 individuals out of tens of thousands over a 40 year period is definitely does NOT indicate a viable population. So, the first thing you should do when attempting to identify a brown recluse is check the distribution map.

Distribution of Brown Recluse Spiders In The U.S.

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The Violin

The brown recluse is probably best known for the dark violin shape on its back; however, several species of spiders are brown and have what some might interpret to be a violin shape on their back. It takes a bit of practice to be able to identify a brown recluse (or what is not a brown recluse), but it is pretty easy once you know what you’re looking for.

For starters, a brown recluse is, well… brown. They may vary from light brown to dark brown, but they will always be brown. As you will later see, the abdomen of the female may be very light in color; almost bordering on off white, but closer to tan to my eye. As for the fiddle or violin shape, it is usually very distinct and darker in color than the rest of the carapace.

The Devil Went Down To Arkansas

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While it is true that other spiders have similar markings, few of them rock the violin like a brown recluse. I don’t want to go into detailed comparisons between the recluse and other spiders, as I plan on making a series of posts on that topic. However, note how the body of the violin marking is on the head of the spider and emcompasses the eyes. It narrows down almost to a point before becoming a line, the neck of the violin, running down the remainder of the cephalothorax. While the general public would consider this the defining characteristic of a brown recluse spider, experts recommend that the general public use a combination of other physical features to confirm the identity of a brown recluse spider.

Legs

The legs of a brown recluse should always be uniform in color. The joints may appear a little bit lighter than the rest of the appendage, but there will never be any spots or stripes. They will also lack spines. Thin hairs may be present, but never leg spines like you would see on some other spiders.

Eyes

Out of all of the recluse’s defining characteristics, the eyes may be the most telling. If you went to Wal-Mart and polled the general public, I’d bet that the vast majority of people think all spiders have eight eyes. While most do, there are several species that only have six, and the brown recluse is one of them. It has six eyes arranged in pairs on the front of the head that form a triangular pattern. Unless you get really close and add a little magnification, it is difficult to distinguish each pair, because they are close together, but the general arrangement is pretty obvious.

Six Eyes In A Pyramid

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Look At The Combination Of Characteristics

Taken individually, any one of these characteristics may describe multiple species of spiders, but if you have a specimen that matches multiple traits, you can be pretty confident that you have a brown recluse.

Male Vs. Female

For some spider species like the black widow or Sydney funnel web spider, the medical significance of the venom depends on whether the spider is male or female. This does not seem to be the case with the brown recluse, but we can still learn to tell the difference between the sexes just for funsies!

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From what I gather, it can be difficult to tell the difference between the two, but I am pretty sure that the image on the left is that of a male brown recluse. Notice the abdomen of each specimen. It is fairly common among spiders for the female to have a more bulbous abdomen, whereas the male is often times more slender. This may have to do with the fact that females spiders have a tendency to den up and stay close to home, whereas male spiders are more nomadic and need to be more nimble.

Next, I would point to the legs. The male brown recluse tends to have longer, spindlier legs in relation to its body size than the female. It does seem to me that the spider on the left matches that description, as well; especially when comparing the middle section of the legs of each specimen.

Finally, we’ll look at the pedipalps; those two appendages on either side of the mouth. Again, in most mature male spider species, the pedipalps will be swollen or enlarged. When comparing these two specimen, it would seem that the spider on the left definitely has larger palps.

I’m no expert, but I believe that the evidence backs me up on this one. If you’re an expert (or even a hobbiest), let me know what you think about it. I’m a big boy and can handle being wrong. {:o)

The Venom

The venom of the brown recluse is of the necrotic type, potentially killing skin and, on very rare occasion, causing red blood cells to rupture. The mechanism by which the venom causes necrosis is not completely understood, but researchers are making new breakthroughs in their understanding. Recently, it was found that the venom contains a protein that attacks the phospholipid layer of skin cells. A phospholipid is made up of two parts: a head portion and a tail portion. The venom appears to cause the tail portions to loop together into a ring. They aren’t quite sure, yet, why this would lead to skin necrosis, but they suspect something about the ring shape is triggering the body’s immune system to attack the affected cells.

What To Do If You’re Infested

First of all, STAY CALM!! Brown recluses aren’t the evil monsters that pop culture makes them out to be. I (very gently) poked, prodded, and manipulated these two spiders for nearly an hour trying to get photos, and they remained very docile. If anything, they were very timid, even resorting to playing dead for several minutes at a time in their attempt to get me to leave them alone. Never once did they rush toward me or lunge at me in an attempt to attack. In fact, these spiders rarely bite unless they are pressed against the skin. Most brown recluse bites occur when reach into dark crevices and press against them or push them against their skin while putting on clothes that have been sitting for long periods of time. Truth be told, bites are exceedingly rare. I’m pretty sure our house was pretty infested with them when I was a kid, and no one was ever bitten. In fact, a Journal of Medical Entomology article authored by Vetter and colleague DK Barger reported that over 2000 brown recluse were removed from a single family occupied home in Kansas over a six month period. Even with all of those spiders running around, not a single bite was ever reported.

And, If I’m Bitten

First of all, STAY CALM!! Not every recluse bite results in rotting flesh; in fact, the vast majority do not. Only about 10% cause necrosis. The other 90% usually cause some moderate skin irritation but will heal without any medical attention at all. That’s not to say that you shouldn’t go to the doctor! The National Institute of Health recommends immediately calling 911 or poison control if you know you’ve been bitten; just realize that it’s probably not going to be as bad as you expect.

The problem is that most people don’t know when they’ve been bitten, as the bite is rather painless. It may take up to 8 hours before the site even begins to feel irritated. For the 90% of bites that don’t cause problems, that’s about as far as it goes. After a few weeks, the bite will have healed, and there probably won’t even be any scarring. However, for the unlucky few, the result of a brown recluse bite can get disgusting or even downright dangerous.

Loxoscelism

Loxoscelism is the term given to the set of complications that can accompany the bite from recluse spiders. It can range from skin necrosis to systemic reactions like nausea and fever or even death in the most extreme cases.

If skin necrosis is going to be a problem, it generally starts off as a small white blister at the bite site surrounded by a dry, sinking, bluish patch of skin with irregular edges. From there, it will begin to form a volcano shaped crater where the skin rots and sloughs off.

One of the reasons that people have such a fear of the brown recluse stems from the misdiagnosis of bites. It is estimated that thousands of skin lesions reported as recluse bites around the nation (many coming from regions where there are no recluse spiders) are actually caused by other factors. Rick Vetter has accumulated a list of at least 40 different maladies that medical professionals have reported as bites, including MRSA and other dangerous bacterial and fungal infections. You can go to Youtube and search for ”brown recluse spider bite” (which I DON’T ** recommend you do**) and see lots of videos of giant raised bumps and people squeezing puss out of supposed brown recluse bites. Those are probably misdiagnoses. Remember, true loxoscelism creates a dry crater.

In Conclusion

Like many of the other creepy crawlies that I write about here on Steemit, the brown recluse has an undeservedly bad reputation. True, they can be dangerous, and any bite or suspected bite should be given immediate medical attention; however, they aren’t out to get you! Thousands of us southerners live side-by-side with them in our homes every day, many without even knowing it, with only the occasional bite. Even if you are bitten, odds are overwhelmingly in your favor! Not only will you likely live to tell the tale, but you probably won’t even have a cool scar to show off to all of your friends.

BUMMER!

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Sources

• North America's most venomous spiders
• Penn State College of Agricultural Sciences Article
• University of California, Riverside: 1, 2, 3, 4, 5
• This Wired.com Article
• An infestation of 2,055 brown recluse spiders (Araneae: Sicariidae) and no envenomations in a Kansas home: implications for bite diagnoses in nonendemic areas from The Journal of Medical Entemology
• University of Kentucky College of Agriculture, Food, and Environment
• This Live Science Article