Lacey Peterson
The Union Democrat

Black widow spider bites

Signs and symptoms of a black widow spider bite may include:

• Pain: Usually within an hour of being bitten, pain generally occurs around the bite mark, but it can spread from the bite site into your abdomen, back or chest.

• Cramping: Abdominal cramping or rigidity can be so severe that it’s sometimes mistaken for appendicitis or a ruptured appendix.

• Sweating: Excessive sweating has been reported in black widow spider bite victims.

W atch out when reaching into or entering dark, rarely used places. A black widow spider could be lurking.

Medical professionals recommend seeking medical attention quickly, especially for bites in children.

According to, someone who gets bitten by a black widow spider might not know it right away, because the bite can sometimes feel like a little pinprick. After 30 to 40 minutes, the area of the bite can swell and become painful, and sometimes a person can get achy all over.

The bites will fester, said Steve Deaver, of Foothill Sierra Pest Control in Sonora.

Deaver said a friend of his was bitten by a black widow and the skin around the wound became red, sore and started to decay.

Other symptoms can include weakness, nausea, vomiting, sweating and headache.

The bite should be washed with soap and water, an ice pack should be applied, and the area should be elevated to help prevent the spread of venom/poison, KidsHealth recommends.

If it’s possible to catch the spider that bit a person, do so carefully and take it to the doctor so they know for sure what bit someone. It can be dead, but not so smashed that it can’t be recognized (if it can be done safely).

According to the Mayo Clinic, if a black widow bite is causing severe pain or life-threatening symptoms (which is rare), a doctor might recommend an antivenom, which can be injected into a thigh muscle or given intravenously. Antivenom can cause serious allergic reactions, so it should be used with caution.

Very rarely, a bite from a black widow spider may be deadly, particularly in children, the Mayo Clinic said.

The University of California Integrated Pest Management Program said that, because the holes, cracks, crevices, trash and clutter associated with human structures are attractive hiding places for the Western black widow, they are very common around homes, barns, outbuildings and in rock walls. In supportive habitats, a mature female can be found every few feet.

“They’re just all over,” said Daniel Harrison, of Sonora, known locally as the “snake and bug guy.”

The spider webs are usually accompanied by an egg sack the size of a pinkie finger, Deaver said.

A sack can have a couple hundred eggs in it, and a female can have several sacks a year, Harrison said.

The females are very protective of their sacks, Harrison said.

Breeding season is from spring to early summer, Deaver said.

Mature females can store sperm from their first mating and can produce more than 10 egg sacs without subsequent matings without a decrease in the number of eggs or a reduction in the percentage of eggs that will hatch into spiderlings, the UC Integrated Pest Management Program said.

A mature female black widow spider is about 1/2 inch long, not including the legs, has a rounded abdomen and is shiny jet black all over her body and legs except for a red pattern on the underside of the abdomen, which looks like an hourglass.

Some have a brownish or plum-colored tinge, but usually these are females that are so well fed the black pigment on the abdomen has expanded until it looks brown instead of black.

They eat other spiders and bugs, whatever they can catch in their webs, Deaver said.

The webs are very strong and feel like strong thread, Harrison said.

Immature widow spiders look nothing like the mother. When baby black widow spiderlings emerge from their egg sac, they have tan legs and tan cephalothorax, the body part to which the legs attach, while the abdomen is mostly white with a few black spots, the IPM program said.

As the spiders grow, the background coloration of the abdomen becomes olive gray, and there is a longitudinal white stripe on the top of the abdomen and three diagonal stripes on the flanks with a small black dot at the uppermost portion of each diagonal stripe.

After the females molt, the white stripes become thinner, the olive gray darkens toward black, and eventually the spider gets its well-known black coloration. Some mature females retain one or two conspicuous, indented white lines on the front surface of the abdomen that look like a corporal’s chevrons.

In the youngest spiders, the space where the hourglass develops starts off as a whitish shield. As the spider grows and goes through several molts, the color of this shield turns from white to yellow to orange to red and changes from a shield with thick a middle to an hourglass with a thin, tapered middle.

Male black widow spiders retain the coloration of the young spiderlings. The males are much smaller than the females in body length, although sometimes their legs are almost as long as the adult female.

Black widow spiders are usually found in places not occupied by people, like in the ridges of the back of a garage door or a basement door, well houses, and other places dark and free of frequent traffic, Deaver said.

The good news is they are fairly slow moving and don’t want to be messed with. They also tend to stay in one place and are pretty stationary.

“They are very shy,” Deaver said.

“The only time you’ll actually get bitten by one is if you step on one or hit one,” Deaver said.

People also commonly get bitten by them when reaching into wood piles.

Harrison often finds them under mobile homes, underneath lawn furniture, drain gutter spouts, corners of attics, ball sheds at schools, and other non-breezy dark places.

They like to have a hiding place that they can come out of at night to patrol for bugs, Harrison said.

“They’re generally scared of us. Most of the time, when people are bit, it’s because we are somehow invading their space,” Harrison said.