Latrodectus hesperus
(Western Black Widow)

Featured spider picture The spider species Latrodectus hesperus, commonly known as Western Black Widow, belongs to the genus Latrodectus, in the family Theridiidae. Latrodectus hesperus spiders have been sighted 22 times by contributing members. Based on collected data, the geographic range for Latrodectus hesperus includes 2 countries and 5 states in the United States. Latrodectus hesperus is most often sighted during the month of July.

Taxonomic Hierarchy

  • Kingdom: Animalia
  • Phylum: Arthropoda
  • Class: Arachnida
  • Order: Araneae
  • Suborder: Araneomorphae
  • Family: Theridiidae
  • Genus: Latrodectus
  • Species: Latrodectus hesperus

Common Name (AASMore information icon)

Western Black Widow

Other Common Names

Black Widow, Black Widow Spider, Widow Spider, Hourglass Spider, Shoe Button Spider, Cobweb Spider, Comb-footed Spider, Tangle-web Spider, Gumfoot-web Spider, Button Spider

Author

Ralph Vary Chamberlin & Wilton Ivie, 1935

Primary Colors


Sightings Overview

There have been 22 confirmed sightings of Latrodectus hesperus (Western Black Widow), with the most recent sighting submitted on April 21, 2018 by Spider ID member bozbitty. The detailed statistics below may not utilize the complete dataset of 22 sightings because of certain Latrodectus hesperus sightings reporting incomplete data.

  • Web: 13% of the time, Latrodectus hesperus spiders are sighted in a spider web (Sample size: 8)
  • Sex: 12 female and 8 male.
  • Environment: Latrodectus hesperus has been sighted 4 times outdoors, and 4 times indoors.
  • Outdoors: Man-made structure (4).

Location and Range

Latrodectus hesperus (Western Black Widow) has been sighted in the following countries: Canada, United States.

Latrodectus hesperus has also been sighted in the following states: Arizona, California, Colorado, New Mexico, Texas.

Seasonality

Latrodectus hesperus has been primarily sighted during the month of July.

  • January: 2
  • February: 2
  • March: 3
  • April: 3
  • May:
  • June:
  • July: 3
  • August: 1
  • September: 1
  • October: 3
  • November: 2
  • December: 2

Additional Remarks

  • Not the only “widow spider” in North America; there are also four other species of Latrodectus.
  • Immature females and adult males retain colorful markings on their abdomen; it’s typically only adult females that may be all black on their dorsal surface.
  • Underside of spider has a bright red or orange hourglass-shaped marking. It may sometimes be faded or (rarely) absent entirely.
  • Females of this species are overall typically larger than the females of Latrodectus mactans or L. variolus.
  • “Deadly” is a misnomer! Human deaths are extremely rare from a widow bite (or any other spider bite, for that matter). Anti-venom exists for treatment, but is rarely necessary; pain medication, muscle relaxers, and/or calcium gluconate are often all that’s needed.
  • Egg sacs are tan or white spheres, about 10mm in diameter, usually having around 100-300 eggs inside; but can be as many as 600 in some cases.

Featured Pictures

Picture of Latrodectus hesperus (Western Black Widow) - Male - Dorsal,Penultimate Enlarge Picture
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Picture of Latrodectus hesperus (Western Black Widow) - Male - Dorsal Enlarge Picture
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Picture of Latrodectus hesperus (Western Black Widow) - Dorsal Enlarge Picture
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Picture of Latrodectus hesperus (Western Black Widow) - Female - Dorsal Enlarge Picture
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Picture of Latrodectus hesperus (Western Black Widow) - Female - Dorsal Enlarge Picture
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Picture of Latrodectus hesperus (Western Black Widow) - Dorsal,Ventral Enlarge Picture
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Picture of Latrodectus hesperus (Western Black Widow) - Male - Dorsal Enlarge Picture
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Picture of Latrodectus hesperus (Western Black Widow) - Dorsal Enlarge Picture
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