Latrodectus

Black widow spiders are arachnids. Female black widows are notorious for their toxic venom. Males lack toxicity and are not likely to bite. The name “black widow spider’ is most commonly used to refer to the three North American species best know for their dark coloration, black hair and red hourglass pattern on their bellies. There are 31 species of black widow spiders.

Identification – What do black widows look like?

Adult female black widows are shiny black with a red hourglass shaped marking on the underside of their abdomen. This marking can also range from white to yellow and various shades of orange and red. Female black widows are approximately 1.5 inches long (including leg span).

Adult male black widow spiders are usually dark brown with varying colors of strips or dots, and do not have an hourglass mark. They are about half the size of the female or even smaller. They have longer legs and smaller abdomens.

Habitat and Habits of black widows

Black Widows prefer to nest near the ground, in dark, undisturbed areas. Nest sites are generally near holes made by small animals, or around construction sites, wood piles, or shrubs. Indoors, black widows prefer dark, undisturbed sites such as behind furniture, undisturbed basements, and crawl spaces.

A female black widow can produce 4-9 egg sacs a summer. Each sac contains 100-400 eggs. The eggs incubate 20-30 days. On average, 30 will survive through the first molting. It takes 6-9 months for a black widow to mature. Black widows live between 1-5 years. The female much longer than the male.

Black Widows build loose, irregular mesh-type webs found on plants, in loose stone, wood piles or in the corners of rooms, garages, and outbuildings.

Black widows typically prey on insects. The prey gets caught in the web, the spider comes out of its retreat, wraps the prey in its strong web, then punctures and injects the venom. The spider holds onto its prey while the venom takes effect (about ten minutes). Once the prey is dead, the black widow takes it back to its retreat before feeding.

Although the black widows venom is extremely potent, 15 times more potent than that of a rattlesnake, they are not especially large. The actual amount of venom injected, even by a mature female, is very small by volume. When this small amount of venom is diffused throughout the body of a healthy, mature human, it usually does not amount to a fatal dose. However, black widow bites can be very dangerous – especially bites to a small child.

Common symptoms of a black widow bite include pain, swelling, numbness, tingling, and redness at the bite site. Muscle pain, cramping, and rigidity in the chest, abdomen, and back can also occur. Other symptoms include tremors (shaking), sweating, rapid breathing, weakness, headaches, nausea, and vomiting. In severe cases, the child may also develop a fast heart rate and high blood pressure. Symptoms most often appear within 30 minutes to 2 hours of the bite. They may last for 24 to 72 hours.

Treatment for a black widow bite includes applying antiseptic to the site, cold packs to ease pain and swelling, medicine to relieve pain and muscle spasms. A tetanus shot may be given if needed. For severe cases, a hospital stay may be needed. Antivenom may be given.

Diet – What do black widows eat?

Black widows eat flies, mosquitoes, grasshoppers, beetles, other arachnids, caterpillars, and anything else that gets caught in their webs – even lizards and snakes.

Black Widow Spider Control – How to get rid of black widows?

Rocky Mountain Bird and Pest technicians are trained to help manage spiders and other pests. Since every home is different, we will design a unique program for your situation. Keeping spiders out of your home is an ongoing process, not a one-time treatment. Once we have treated your home, we will implement a solution to keep spiders out of your home.