By Staff
Recently one of my wife's co-workers thought her son was bitten by a spider. Like many folks would, her thoughts went straight to the brown recluse. It's amazing the notoriety the brown recluse spider carries. Somehow they have gained the reputation of being even more deadly than the black widow. Actually, the gal and her son had little to worry about. It will surprise many of you that the brown recluse is not native to this area. In fact, no populations have ever been documented in Michigan.
That's not to say there couldn't be one in these parts, though. The brown recluse is native to the Southern and Central Midwest, ranging from Texas up to Central Illinois and Indiana. Unlike the black widow which prefers outdoor habitats, the brown recluse is primarily an indoor spider. Therefore, it's not uncommon for one to be hanging out in some pallet, box or stack of clothing and then get shipped off to far away places. In this manner individual brown recluses have turned up all across the country. Fortunately, it's usually just one spider so it cannot establish a breeding population.
Most people envision the brown recluse as being a big, hairy monster on the order of a mini tarantula. They're actually quite small. With legs outstretched they're about the size of a quarter but the body itself is only about three-eighths of an inch long. Their color varies from tan to dark brown and a covering of minute hairs give their body a velvety look. One of the key identifying features is a dark brown to black marking at the front of the upper body shaped like a violin with the neck pointing towards the rear. This isn't conclusive evidence as there are other spiders with similar markings but this combination of size and features should be a caution warning.
The name recluse is well suited. They are strictly nocturnal and spend the day hiding in secluded areas. Behind and underneath furniture, behind pictures and baseboards and in inconspicuous cracks and crevices is where the brown recluse hangs out. They may spin an irregular, sticky web for a home but they don't use it to catch prey like most other spiders. An hour or two after dark the brown recluse leaves its sanctuary and goes on the prowl in search of dinner. Their primary food source is cockroaches but they'll take anything from flies to ants and other spiders.
Brown recluses are not the least bit aggressive. They only bite when physically threatened. Most bites come when a sleeping person rolls over onto them or someone sticks their foot in a shoe or puts on clothing where the recluse happens to be hiding. In Missouri and Arkansas, the heart of their range, 70 percent of the houses host brown recluses, often numbering in multiple dozens, but bites are still rare.
There have been a few deaths from brown recluse bites but they are extremely rare. Few people die from a black widow bite, either, but the black widow is the worse of the two. A widow's venom mostly affects the nervous system, causing cramping, tremors, nausea, dizziness and breathing difficulties. The brown recluse's venom attacks tissue. The bite itself is just a slight pinprick sensation. The severity depends on how much venom is injected and an individual's reaction to the venom. In most cases there's little affect. The bite area will swell a little and then disappear in a day or two. In more severe reactions the bite at first usually shows little symptoms. Then, several hours later a small white blister and minor swelling occurs. That may progress to the area turning red with increased swelling and intense pain. That can progress into a blue-gray sunken lesion surrounded by redness. In the worst cases severe tissue destruction occurs causing a deep, open, gangrenous wound ranging in size from a thumbnail to an outspread hand. Unlike with widow spiders, there's no antivenin for recluse bites.
So now you know. Here in Michigan you needn't freak out at every brown spider you encounter, only the one in that box Aunt Mildred from Arkansas sent you. Carpe diem.