Brown Recluses

 When I was a kid, I knew nothing about brown recluses.  It's no wonder; this spider wasn't described scientifically until 1940 (meaning NOBODY knew about brown recluses until after that point), and wasn't really studied until the early 1960s.  I was a kid in the 1950s and 60s.  I wonder now how many recluses I saw in the house growing up, not knowing how dangerous they could be. Where were all those horrific brown recluse bites back then?  We've all heard the horror stories about huge rotting wounds from the venom of this shy and unassuming spider.  Were bites prior to the 1960s diagnosed as something else?

Actually, there are a lot of misconceptions about the recluse.  It is one of the two Missouri spiders that can be dangerous to humans, but though it is a very common spider throughout its range, bites are rare.  In fact, according to most authorities, bites are far more rare than most people believe.  The tissue necrosis caused by severe brown recluse bites is similar to that brought on by many other causes, including infections such as MRSA.  Doctors, who are seldom knowledgeable about spiders, often misdiagnose otherwise unexplained wounds as spider bites, especially if the person presenting the symptoms suggests (or swears) they have been bitten by a recluse.  For instance, there has never been a live recluse found in California--it is well outside the range of the brown recluse, although parts of southeastern California do have a related species, the desert recluse.  Yet there are hundreds of reports of brown recluse bites in the most populated parts of California, outside even the desert recluse's range.  Medical authorities now believe nearly all these cases were not spider bites at all.  There have also been a number of bites reported in Maine, which is far north of anywhere brown recluses have been found--it is a southern species with Missouri one of the northernmost states that harbor large numbers of recluses.

There is no doubt, however, that brown recluse bites causing serious tissue damage do occur.  Reactions to recluse bites are dependent upon the amount of venom injected, and the sensitivity of the victim to the venom, with 90% of bites not requiring medical attention.  Many bites cause only a small red mark that quickly disappears, and the vast majority do not cause significant wounds or scarring.  However, a "bad" bite really can be a horror story.  It is seldom painful when it happens, but usually starts with a small, white blister, which becomes a hard bump, then a dry, bluish or purplish lesion surrounded by redness.  From there it can progress to a growing area of dying tissue, causing a deep wound than can become as large as 6 inches across. If a bite is going to cause necrosis, it will turn purple in color within 48 to 96 hours, and then black as the tissue dies, with the necrosis eventually falling away, leaving a deep pit that gradually fills with scar tissue.  According to the NIH, a bite can also cause chills, fever, nausea, sweating, and general discomfort.  There is no antivenom for recluses, and treatment consists of taking care of the wound.  Medical sources advise that if you're bitten by a recluse, wash the bite area with soap and water, then wrap ice in a washcloth and apply it to the bite for 10 minutes, remove for another 10 minutes, and repeat until you can get to an emergency room.  My wife Mary was bitten by one when she put on clothing where it was hiding, and her bite progressed to the hard, white bump stage, but eventually disappeared. It was quite painful for several days, but we did not seek medical attention for it.

Because of the questionable reporting of other infections as brown recluse bites, it is impossible to ascertain just how many people are bitten each year.  But according to the latest information, there have been no fatalities from the effects of brown recluse bites in North America.  So recluses aren't quite as fearsome as the urban legends suggest.  I would bet that nearly every home in the range of the recluse, including Missouri, harbors at least a few recluses.  And they can be incredibly numerous.  In one example, scientists collected 2,055 recluses from a single house in Kansas!  But you seldom see them because they are well-named; they hide during the day.  Recluses are entirely nocturnal.  The females build wispy patches of webbing as part of their home, but do not use the weak webbing to capture prey.  They tend to stay in the vicinity of their lair, but males are entirely roaming hunters.  Recluses seem to really like cardboard, perhaps because it is similar to their habitat in the wild, hidden areas beneath logs and tree bark.  Stacked cardboard boxes in a garage, basement, or attic are great recluse hiding places.  You can also find them behind picture frames on your walls, and if you really want to start having nightmares, try getting up in the middle of the night and switching on the lights in any room of your house; chances are you'll see some recluses on the floor near your baseboards, since they like to hide in the thin crack between the baseboard and the floor during the day, and come out under cover of darkness.  While it's definitely an urban myth that the average person swallows so many spiders in their life while sleeping, recluses do roam around at night, and I've had a few crawl across me while I was in bed.  You will also often find one in your sink or bathtub.  Many people think they must come up out of the drain, but in reality they fall into the sink or tub while roaming at night, and it's too slippery for them to escape.  If you have a noticeable infestation of recluses in your house, it's not a good idea to leave clothing on the floor for a day or more because they find that a very good hiding place.  You should also shake out clothing that has been lying around, or even in your drawers, before donning it; most bites, like Mary's, happen when someone puts on clothing where a recluse is hiding.  Their fangs are not long enough to bite through cloth, but bites occur when the spider is pressed against your skin by the clothing.

Recluses are small to medium size, nondescript brownish spiders; their main identifying feature is the dark violin shape on the top of their carapace (the front part of the body).  This marking is usually quite distinctive, though it requires observing the critter from a fairly close vantage point.  They way they hold their legs is distinctive if you are already used to seeing recluses, but difficult to describe.  They can be various shades of brown but are otherwise unmarked.  They are not obviously hairy, but their abdomen is covered by very fine, short hair that gives it a slightly velvet appearance.  The males are slightly smaller than the females, but with longer legs in relation to their body size.  Spiderlets are like lighter miniature versions of adults.

The female usually mates with one male at a time, and will try to eat him after mating.  She deposits her eggs in a white silk pouch about the size of a dime, usually attached to a vertical surface and surrounded by wisps of webbing.  The exoskeleton of the male she mated with may be stuck to the silk near the pouch.  These exoskeletons also remain after the spiders molt, and you will commonly see them loosely attached to surfaces such as cardboard when there are recluse present, appearing as translucent legs and carapace.

The females often produce more than one egg sack, with 30-100 eggs per pouch.  Some eggs get eaten by spiderlets from previous hatches that remain in the web.  Eggs hatch in about 13 days, and by about 50 days later the young are mature.  Recluses have been known to live up to 894 days, and they can live for over six months without food or water.  They are also somewhat resistant to pesticides.  Commercial pest control measures are seldom really effective at ridding a house of recluses; their chief effect is in removing the insects that the recluses feed upon.  But insecticides may also kill the predators of recluses, such as wolf spiders, so they are questionable as a control measure.  Sticky traps around anywhere recluses can hide can reduce their numbers--and it is often disconcerting to see how many recluses you can catch in a sticky trap!  But the best control measure is simply to declutter your house as much as possible.

Another interesting thing about brown recluses is that if a predator grabs them by the leg, or another spider like a wolf spider bites their leg, they can easily detach themselves from that leg to escape and minimize envenoming.  Unlike some spiders, they cannot regrow a lost leg, but they adapt very easily to losing one, altering their gait to compensate.  They can do just fine with as few as four legs, as long as they have at least one leg left on both sides.

There are several other species of recluses, but they are limited to the Southwest from eastern California (the desert recluse) to south Texas, mostly along the Mexican border.  In addition, a "foreign" species, the Mediterranean recluse, occasionally shows up in various parts of the U.S. by hitchhiking in commercial trade.  It is almost identical in appearance to the brown recluse.  Recluses, because of their propensity for hiding in things like cardboard boxes, are probably transported to parts of the country outside their native range, but there is no evidence of significant breeding populations resulting from these introductions.  

Black Widows

I encountered my first black widow spider when I was about seven years old. The house where I grew up in Missouri had a basement that only extended to within about 15 feet of the front of the building; that last 15 feet was a dirt-floored crawl space. There was a door leading into it from the basement proper, and just inside the door the dirt had been excavated to the level of the basement floor in a ten foot square "room" we called the "coal bin hole". There was a small door through the foundation there, and back in the days when the house had been heated by coal, that was where the coal was unloaded. I often explored the coal bin hole to see what kind of bugs I could find, but one day I was shining a flashlight into one of the corners, and there was a big, fat black widow in its web. I'd heard plenty of horror stories about black widows, and I quickly retreated; it was a couple years before I got up enough nerve to go into the coal bin hole again!

I always seem to picture black widows in such places, even though most of the other widows I've found have been in the outdoors. I have found them in woodpiles and under rocks. In Montana, I was doing landscaping at the cabin that was our first dwelling there, and found five different widows under the round river rock I was picking up from around our 20 acres to use to line the parking area. In Missouri, I've found a few in out of the way corners in barns and sheds. But really, they don't seem to be all that common in most of the places I've lived.

There are five widow species in the U.S., though more than 30 species in the genus are spread across the world. The most common species in Missouri is the southern black widow, Latrodectus mactans, though the northern black widow, L. variolus, is also widespread across the state.  The spiders I encountered in Montana were western black widows, L. hesperus--their appearance is very similar to southern widows.  The red widow, L. bishopi, has a dark brownish or black abdomen with a red spot that is often a triangle on the underside and various red spots with yellow borders on the back and sides, and reddish brown cephalothorax (head portion) and legs.  The brown widow, L. geometricus, has a brown body with the typical red hourglass on the underside of the abdomen, and legs that are banded with dark and light brown.  The northern black widow is found across the northeastern quarter of the U.S. as far north as southern Canada and south to Missouri.  The southern widow is found across the South and Southeast from Arizona to Florida, and north to Missouri and Virginia.  The western widow ranges from British Columbia to Mexico and as far east as Colorado.  The red widow is confined mainly to Florida, and the brown widow is a tropical and subtropical species that was not native to North America but now has established populations across the southern tier of states.  All these species have similar venom and body shape, and are found in similar habitats. 

Black widow males are no more than 1/4th the body size of adult females, but have longer legs and more colorful bodies, with various white, red, and yellow stripes and spots.  

In the wild, black widow habitats are crevices in and beneath rocks and logs, holes in embankments, and other dark, sheltered areas.  But they readily use human structures, including sheds and outbuildings (and outhouses!), water meter holes (I'm always concerned when I lift the cover off the valves in my irrigation system at our place in Montana, and so are the guys that service the system), and under any large object that has been undisturbed for a while.  They are seldom found indoors in houses, but occasionally will come inside as cold weather descends.  Perhaps the one widow I found all those years ago in the coal bin hole came in during the autumn.

One of the most famous characteristics of black widows, and where they get their name, is that the female kills and eats the male after mating.  However, according to most authorities this seldom happens in the wild; it was observed in captive situations where the male had no chance of escaping.  Females build haphazard three-dimensional webs with little structure other than a dense area to the rear where the female hides.  The male enters the web and mates with the female, and then at least attempts to escape.  Males also often dismantle portions of the web, tearing them apart, rolling the silk up, covering it with their own silk, and removing it from the vicinity.  This is believed to be for the purpose of removing the scent of other males from the area in order to monopolize the female; females will mate with several males, and can produce up to nine egg sacs in a summer, each with an average of 400 eggs.  The spiderlets are very cannibalistic, and few survive the two to four months to maturity.  Adults are preyed upon by mud dauber wasps.

While black widow webs are far from artistic, the silk ranks among the strongest of all spider silk.  Like most web-building spiders, the female lurks in the rear of the web, waiting for vibrations to signal that a prey insect has entered--widows have very poor eyesight.  The female then quickly emerges, bites the prey, and holds it tightly.  The venom takes about ten minutes to take effect, and and when the prey stops moving, she releases digestive enzymes into the bite wound and carries the insect back to her retreat before feeding.

Unlike brown recluse venom, the venom of Latrodectus species is a neurotoxin, and the effects are quite different from the tissue damage that recluses are famous for.  Widows are reluctant to bite, and people usually get bitten when the spider is pressed against the skin, often by reaching under objects where the spider is found.  Putting hands in gloves that have been sitting undisturbed, or feet in boots that have been sitting for a while, is another good way to get bitten.

The southern black widow is reputed to have the most potent venom, while the brown widow has the least severe bite symptoms--it may not be dangerous at all.  Often the bite will be dry, with no venom injected, and the severity can vary due to the amount of venom injected.  A bite may first be felt only as a pinprick as the extremely small amount of the potent venom is injected, but quickly swelling and redness around the bite appears, and in one to three hours there is severe pain which often moves through the body and settles into the back and abdomen.  Intense muscle and abdominal cramping can last for more than 48 hours.  Nausea and profuse sweating are common, along with chills, fever, headache, and severe high blood pressure.  Tremors, convulsions, and unconsciousness can happen with untreated bites, and if death does occur it will be due to suffocation.

Treatment of black widow bites usually consists of treating the symptoms.  There is an antivenom available, but it is usually only administered to those at highest risk, such as young children, the elderly, or those with heart conditions. Victims usually recover within two to five days.  Deaths are rare; about 2,600 black widow bites are reported in the U.S. in an average year, resulting in 7 deaths.