Spiders

There are over 35,000 described species of spiders worldwide, with about 3,000 occurring in North America. Many species of spiders are household pests. Wherever their food is available, spiders are likely to be found. All spiders are predators, feeding mainly on insects and other small arthropods.

Black Widow Spiders

Black widow spiders are most recognized for the red hourglass shape on the back. Contrary to legend, female black widow spiders rarely devour the male black widow spider after mating.

Pest Facts

Color: Black, with characteristic red “hourglass” on back
Legs: Eight
Shape: Round
Size: 3/4 inches length; 3/8 inches in diameter
Antennae: No
Flying: No
Region: All 50 States

Habits

Black widow spiders spin their webs near ground level. They often build their webs in protected areas, such as in boxes and in firewood.

Habitat

Black widow spiders are often found around wood piles and gain entry into a structure when firewood is carried into a building. They are also found under eaves, in boxes, and other areas where they are undisturbed.

Threats

The venom of a black widow spider is a neurotoxin and is used as a defense. Black widow spiders do not bite humans instinctively. The black widow spider bite can cause severe pain. Young children and the elderly are especially susceptible to a severe reaction to a black widow spider bite.

Avoid black widow spider bites by wearing heavy gloves when moving items that have been stored for a long period of time. Spiders often hide in shoes, so check shoes and shake them out before wearing. When spider webs are visible, use caution before putting your hands or feet in that area.

Brown Recluse Spiders

Brown recluse spiders have a characteristic dark brown violin marking on their back.

Pest Facts

Color: Light to dark brown, with characteristic dark brown violin marking on back
Legs: Eight
Shape: Round
Size: 5/8 inches
Antennae: No
Flying: No
Region: TX, LA, AR, OK, MO, KS, NE, IA, MO, IL, IN, OH, KY, TN, MS, AL, GA

Habits

Brown recluse spiders are nocturnal and eat other bugs like cockroaches and crickets. Male brown recluse spiders wander farther than females and will crawl into shoes or other clothing.

Habitat

Brown recluse spiders often live outdoors in debris and wood piles. They can be found indoors in storage areas and dark recesses.

Threats

Like the black widow spider, the brown recluse spider bites in defense and does not bite humans instinctively. They will bite humans when the clothing they are hiding in is worn. The brown recluse spider bite is painful and can produce an open, ulcerating sore.

To avoid brown recluse spiders, avoid keeping clothing on the floor. Store clothing and shoes inside plastic containers, and shake out all clothing that has been in a hamper before wearing or washing.

Yellow Sac Spider

Brown recluse spiders have a characteristic dark brown violin marking on their back.

Pest Facts

Color: Pale yellowish-green.
Legs: Eight
Shape: Round
Size: 1/4 inches
Antennae: No
Flying: No

Habitat

The yellow sac spider is common throughout the eastern United States, in particular from New England through the Midwest. It is normally an outdoor spider but will readily enter and breed inside homes and other buildings. The silken “sac” retreats are usually seen in corners along baseboards, along the ceiling, and beneath and behind furniture. Outdoors, the sacs will be found beneath the bark of trees and under items such as stones and logs. Sacs may also be found along soffits, beneath window sills and around door frames.

The best approach with this spider is to find, destroy and remove the sacs and the spiders hiding within.

Steps to be taken to prevent new spiders from entering include:

  • Removing or limiting heavy, ground-covering vegetation near the home.
  • Sealing cracks and holes in the building’s exterior.
  • Installing tight-fitting screens on all attic and foundation vents.
  • Sealing holes around pipes indoors to prevent spiders from entering the living spaces of the home from basements and crawl spaces by following plumbing lines.

Where numerous spiders and bites have occurred, a professional should be consulted to conduct a thorough inspection and recommend possible treatments.

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