A Glimpse Into Black Widow Spiders

Black widow spiders are venomous spiders. They are not usually deadly, especially to adults, because they inject only a small amount of venom. Despite its reputation, it often attempts to escape rather than bite, unless it’s guarding an egg mass or if it is cornered and pressured.

After mating, the female sometimes eats the male, earning the name “widow.” The female black widow is the most easily recognized. She has a shiny black body which gives great contrast to the red hourglass marking on her round abdomen. Adult black widow males are harmless, about half the female’s size, and usually have yellow and red bands with spots on their backs. The legs of the male are much longer in proportion to his body than that of the female.

Black widow spider webs are usually built near the ground, (occasionally within dwellings) normally in trash, rubble piles, under or around houses and out-buildings such as sheds and garages. They can be found under eaves, in storage bins, underneath unused construction materials, inside wooden toy boxes, firewood boxes, outdoor toilets and sheds, meter boxes, and other undisturbed places. Black widow spiders can be found on the underside of ledges, rocks, plants and debris, or wherever else a web can be strung. Cold weather and drought may drive these spiders into buildings.

The female black widow spider rarely leaves her web. The web she constructs is an irregular, tangled, criss-crossed web of rather coarse silk. This same web may be rebuilt or changed on an ongoing basis depending upon her needs. The female spider spends most of her daylight hours inside her web. She is often found hanging upside down. The female captures her victims with her silk, wrapping it around the prey. After the covering of silk, the prey is killed by an injection of venom. The prey might be eaten immediately or reserved for a later feeding.

Female black widows stay close to their egg mass, defensively biting anything that disturbs her or her egg sac. Egg sacs are oval, brown, papery and about ½ inch long. They hold from 25 to 750 or more eggs, which have an incubation period of 20 days. Newly hatched spiders are predominately white or yellowish-white, gradually acquiring more black and varying amounts of red and white with each molt. The female black widow stores sperm, producing more egg sacs without mating. Some female black widows live more than three years.

If bitten by a black widow spider:
• You may not always feel the bite at first.
• The first sign of a bite is small, local swelling.
• There may be two small red spots in the center of the swelling.
• Clean the site of the bite with soap and water.
• Apply a cool compress over the bite and keep the affected limb elevated to heart level.
• Treatment in a medical facility may be necessary for children under five years old or for adults with severe symptoms.
• After three hours, the site of the bite becomes more painful.
• Common reactions include an overall ache of the body, in particular the legs.
• Other symptoms include alternating salivation and dry-mouth, paralysis of the diaphragm, profuse sweating and swollen eyelids.
• In severe cases, a headache, elevated blood pressure, nausea and perspiration could occur.
• The poison injected by the black widow can cause abdominal pain similar to appendicitis as well as pain to muscles or the soles of the feet.
• In most cases symptoms disappear in two or three days.
• Calcium gluconate is used intravenously to relieve muscle spasms produced by black widow venom.
• The victim of a black widow bite should go to the doctor immediately for treatment

If you’re experiencing any problems with black widow spiders, call the pest control professionals at Rove: 651-735-3101. A friendly pest control expert from one of our 4 Minnesota offices (in St. Paul, Minneapolis, Oakdale & Brooklyn Park) will be able to help.

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