4954 N. Shamrock Place, Tucson, AZ 85705

Black Widow Spider

Lactrodectus mactans

Black Widow Spider

Physical Features

Black widows have eight legs and two body parts like all spiders. They have specific markings used for identification, but these markings vary and can make identifying difficult. Females are 1/2 inch long, shiny black with a red hourglass shaped marking on a round abdomen. Males are black with red spots and white lines going out to the side. They are half the size of the female. Spiderlings are orange and white in color turning blacker with each molt.


  • Diet: Insects
  • Activity: Nocturnal
  • Preferred Climate: Temperate climate
  • Defense: Web. Females bite if disturbed. Males do not bite. They bite their prey releasing a neurotoxin, paralyzing their prey so they can suck their prey’s fluids.
  • Cautions: Black widow bites are painful resulting in localized pain, severe cramping, nausea, sweating, fever, etc. A physician should be consulted if bitten since reactions vary due to person and amount of venom introduced.
  • Home Invasion: Black widows enter a home in search of shelter. They live in solitary. Normally found in sheds and garages or other areas that are darker and less trafficked.

Helpful Hints

  • Remove debris around the home that black widows may inhabit.
  • Wear gloves when working in areas that black widows may be residing.
  • Recommend regular pest control service plan.

Interesting Facts

Contrary to popular belief, the female black widow does not always kill her partner after mating.


Minimal to sharp pain followed by swelling and redness.

Nesting Sites

  • Special attention to outdoor areas
  • Activity around the perimeter of structures. Migration of materials indoors.