Size: Body may be up to 3/4-inch in length with the abdomen reaching 3/8-inch in diameter.  Color: Typically glossy black but may also be dark brown to light brown. Related widow spiders may be brown.

The characteristic red markings on the underside of the abdomen often connect to form an hourglass shape, but this does not always occur. The black widow spider is widely feared because its bite results in severe pain that may take several days to subside. Such bites are rarely fatal but small children and elderly persons are at risk.

Black widow spiders construct irregular, scaffold-type webs usually near the ground level. These webs are almost always constructed in a protected site such as among items piled together, beneath boards, in firewood, and between boxes. Newly hatched spiderlings climb to highpoints, release a strand of webbing and are propelled by "ballooning" to new locations.  For this reason, buildings may have new spiderlings float to it on a regular basis. Most of  these do not survive. Black widows eat any insect they can capture. It is not true that the female always consumes her mate after mating, but it does frequently occur.

Black widows are classified as dangerous spiders because their bite can cause severe cramping and pain throughout the body. Very young children, the elderly, and very ill persons are most at risk for severe reactions to the bite of this spider.   Bites most frequently occur when people are picking up an item under which the spider is hiding or putting on a shoe the spider has crawled into. Many bites are reported in outhouses where the black widow likes to spin her web below the toilet seat. (Be sure to check carefully before sitting down!)

Black widows prefer to construct their webs in secluded, protected sites where insects are more likely to show up. Such sites are common in items stored haphazardly in garages or outside. Such clutter creates innumerable spaces suitable for spider harborage.  Keeping boxes and objects stored neatly and away from walls is one step to minimize these spiders in or around a home.

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Control

Mechanical control measures can be very effective for immediate and long term control.  What we mean by "mechanical control" is simply locating spiders and webs and physically destroying them.  Use the Webster for brushing out spiders and their webs.  By regularly removing old webbing, you can easily determine new activity, and it also removes their food sources in the webs making their environment uninhabitable. 

Treat with a residual insecticide such as Talstar, Tempo, or Suspend, around the foundation of the structure, window frames, door frames, soffit areas, vent openings, exhaust areas, garages, basements, mounted lights, air conditioning areas, cable entry points, deck areas, stoop and patio areas.

Using DRIONE DUST, or DELTA DUST in the attic area would be a good measure if there is an infestation in that area. Or you can apply Delta Dust to your crawl space, as it is moisture proof.

Dusting is useful if there are voids such as electric outlets, switch plate covers or vent areas where spiders are emerging. Using a duster like the White Crusader, would allow for easier dusting.

Utilize the incorporation of glue board spider traps for the capture and elimination of foraging spiders.  Trapper Max Glue Boards are sold in packages of 72.  Set them out in dark areas where spiders might be hiding or foraging.  Maintaining sticky traps behind furniture, to either side of exterior doors, and in the garage is an excellent way to intercept most spiders as they enter.

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According to Willia Gertsch, curator of spiders at the American Museum of Natural History, New York, the venom of the black widow spider is 15 times as toxic as the venom of the prairie rattlesnake. However, only a minute amount of the toxin is injected with a single bite by the spider, while the relatively large amount of injected rattlesnake venom results in about 15 to 25 percent mortality among those bitten.

The severity of a person's reaction to the bite depends on the area of the body bitten, amount of venom injected, depth of bite, seasonal changes and temperature. The bite feels like a pin prick or is not even felt. At first, there may be only slight local swelling and two faint red spots surrounded by local redness at the bite. Pain becomes intense in one to three hours and may continue up to 48 hours. Pain usually progresses from the bitten member up or down the arm or leg, finally localizing in the abdomen and back. The abdominal muscles may become rigid and board-like with severe cramps (resembles appendicitis).

There may be pain in the muscles and soles of the feet, and eyelids may become swollen. Other symptoms may be nausea, profuse perspiration, tremors, labored breathing and speech, and vomiting. During this time, a feeble pulse, cold clammy skin, unconsciousness, convulsions and even death may result if the victim does not receive medical attention immediately.

Additional complications may occur due to the infection of the bite. However, with some untreated individuals, symptoms may diminish in several hours and be gone in several days after agony. Bites are uncommon and serious long-term complications or death are rare. Only four deaths were officially attributed to black widow bites in the United States from 1960-69.

First Aid

If bitten, remain calm, collect the spider, if possible, for positive identification and get medical attention immediately. (Contact your physician, hospital and/or Poison Information Center.) First aid is of limited help. Application of a mild antiseptic such as iodine or hydrogen peroxide prevents infection.

Persons younger than 16 and older than 60, especially those with a heart condition, may require a hospital stay. (Health and lung failure may result in death.) A physician can give specific antivenom or calcium gluconate to relieve pain. Healthy people recover rapidly in two to five days.