Black Widow Spider

Actual Size: 1/4″ to 1/2″ body length

Characteristics: Females are jet black with two reddish triangular markings, forming an “hourglass” shape on the underside of the abdomen. The markings of immature spiderlings and mature males are similar—light brown, orange, or white in color with light streaks on their abdomens.

Habits:

  • The black widow’s web is a mass of fibers with a small central area where the spider waits for prey to become ensnared.
  • Webs are frequently constructed underneath boards, stones, and outdoor furniture, inside irrigation boxes, behind shrubs and especially where brick or wood siding extends close to ground level.
  • The black widow does not usually enter residences, though it may do so on occasion.
Category:

Pest Description

BLACK WIDOW SPIDER IDENTIFICATION

No other spider causes as much apprehension as the black widow spider. Because they thrive in warmer temperatures, black widows are most common in the south and western regions of the United States, but can be found in all 50 states.

The adult female is usually jet black with two reddish triangular markings, forming an “hour glass” shape on the underside of the abdomen. Mature females are nearly 1/2 inch in body length and males are about half this size. The markings of immature spiderlings and mature males are similar—light brown, orange or white in color with light streaks on their abdomens.

BLACK WIDOW SPIDER LIFE STAGESPest property threat level - LOW

Black widow spiders mate in the spring or summer. Female widows lay eggs in sacs that are round or oblong in shape. Sacs are white, tan or gray in color and have a paper like texture. These sacs contain up to 400 eggs and are suspended within the web, with the female keeping guard nearby.

Spiderlings hatch four weeks later, however, many of these will not survive because black widow spiders eat one another in the early stage of life. Female black widow spiders typically live an average of 18 months, while males only survive between two to five months.

BLACK WIDOW SPIDER THREATS

Black widow spider venom contains toxins that are neurotoxic (toxic to the nervous system). Although their venom is said to be 15 times more potent than that of a rattlesnake, death due to a black widow bite is rarely reported. Black widows are reclusive in nature and only bite when provoked or disturbed. Children and pets are commonly bitten by black widow spiders when they are curious and accidentally invade a web, surprising the female.

People and Pests Threat Level of this Pest - VERY HIGHThe bite of a black widow produces a sharp pain similar to a pinprick and leaves two faint red puncture wounds. Symptoms of a black widow bite usually start within 20 minutes to one hour after being bitten and can include intense pain and stiffness in bite area, severe abdominal cramping, chills, fever and nausea. It is imperative to seek immediate medical attention if a bite is suspected.

BLACK WIDOW SPIDER EXTERMINATION AND CONTROL

Follow these tips to prevent black widows from taking up residence on your property:

  • Eliminate the food source: Black widows feed on other insects. Reduce the number of insects by utilizing regular pest control to prevent an infestation.
  • Use gloves when gardening and when working in garages, sheds or barns.
  • Remove clutter in garages and sheds where black widows like to hide. In storage areas, keep boxes and bins up off the floor and away from walls.
  • Using gloves, periodically check the undersides of outdoor play equipment, patio furnishings, potted plants, and irrigation boxes.
  • Trim back vegetation around the home, seal cracks and crevices and remove any debris to discourage insects and spiders from gaining entrance to the residence.
  • If you notice black widows or signs of an infestation, contact a professional for a proper course of black widow spider control.
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