Common Missouri Pest: Black Widow Spiders

Black widow spiders are the second group of spiders which are potentially threatening to humans. A black widow spider is dark to black in color with a red hour glass marking on the underneath side of its abdomen. This spider gets its name by virtue of the unkind act of butchering and devouring its mate after the reproductive process. The presence of sexual cannibalism has inspired the common name “widow spider.”


Black widow spider venom contains the neurotoxin latrotoxin, which is potentially dangerous to humans. A bite may result in systemic effects including muscle pain, nausea, vomiting, abdominal cramps and muscle spasms. Symptoms usually last from three to seven days, but may persist for several weeks. The female black widow has unusually large venom glands making its bite severe, however, rarely if ever are these bites fatal and there don’t seem to be any long term adverse effects from this encounter.  Bites are usually the result of a chance or casual contact and are deemed to be by accident. They bite out of defense because they are encroached upon during unsuspecting human contact. These spiders live mostly outdoors and in fields. This spider may be found in yards but, rarely will they be found inside a home.


The black widow spider constructs an irregular web consisting of tangled, sticky, silken fibers. This spider (much like a cellar spider) frequently hangs upside down near the center of its web and waits for insects to blunder in and get stuck. These spiders have very poor eyesight and depend on vibrations reaching them through their webs to find trapped prey. They are passive hunters and therefore, don’t forage for food.

If you suspect a black widow spider presence in or around your home or office, contact the professional pest management team of Bugs by Brian at (636) 394-0101 to eradicate this pest. We offer special rates on power spraying the exterior of buildings and surrounding grounds.