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​​​Black Widows




  • Female black widows are approximately 1.5 inches long, while males grow to only a quarter of the female's size
  • They have a round cephalothorax (united head and thorax)
  • 8 long, slender legs
  • Females are generally shiny black or dark brown, while males are light brown or gray
  • Males have knob-like structures that extend from their heads, called pedipalps
  • Females have a red or orange-ish, hour-glass-shaped mark on their abdomens

Black widows usually do not harm humans, unless they feel threatened or they bite in self-defense; however, black widow venom is neurotoxic.

What Attracts Black Widows?

  • Any type of temperature or environment can attract black widows because they can survive in most conditions
  • Holes, cracks, and crevices associated with human structures
  • Trash and clutter
  • Plants
  • Shady areas where sunlight is not abundant
  • Moisture

Prevention of Black Widows:

  • Remove or reduce trash, rubbish, and clutter
  • Keep your front and back yards free from tall grass, weeds, or shrubs
  • Vacuum corners of rooms, under sinks, furniture, closets, garages, outdoor storage areas, and crevices often
  • Fix any holes in windows, walls, or screens
  • Ensure that windows fit tightly
  • Keep doors closed as much as possible
  • Insecticides can reduce infestations of spiders

Treatment of Black Widow Bites:

  • Wash the bitten area with soapy water
  • Apply a cold ice pack or a warm compress to the affected area to reduce pain and swelling
  • Elevate it if your bite is on an extremity
  • Take acetaminophen and ibuprofen to relieve pain
  • Go to an emergency room or contact your doctor right away if you have an adverse reaction to a black widow bite

Printable brochure on Black Widows​

West Valley Mosquito and Vector Control District​