Latrodectus hesperus: Difference between revisions

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Image:Black Widow making web.jpeg|Typical female from California.
Image:Black Widow making web.jpeg|Typical female from California.
also known as Cate Biggs

Revision as of 01:18, 3 March 2010

Latrodectus hesperus
Latrodectus hesperus 1.jpg
Latrodectus hesperus female
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Arachnida
Order: Araneae
Family: Theridiidae
Genus: Latrodectus
Species: L. hesperus
Binomial name
Latrodectus hesperus
Chamberlin & Ivie, 1935[1]

Latrodectus hesperus, the Western black widow spider or Western widow, is a highly venomous spider species found in western regions of the United States of America. The female's body is 14–16 millimeters in length and is black, often with an hourglass shaped red mark on the lower abdomen. The male of the species is around half this size and generally a tan color with lighter striping on the abdomen. The population was previously described as a subspecies of Latrodectus mactans and it is closely related to the northern species Latrodectus variolus. The species, as with others of the genus, build irregular webs, the strands of which are very strong.

The female's consumption of the male after courtship, a cannabilistic and suicidal behaviour observed in Latrodectus hasseltii (Australia's redback),[2] is rare in this species. Male Western widows may breed several times during its relatively shorter lifespan.[3]

The ultimate strength and other physical properties of Latrodectus hesperus silk were found to be similar to the properties of silk from orb weaving spiders that had been tested in other studies. The ultimate strength for the three kinds of silk measured in the Blackledge study was about 1000 MPa. The ultimate strength reported in a previous study for Nephila edulis was 1290 MPa ± 160 MPa[4]


also known as Cate Biggs


Male Western Black Widow - This image shows the enlarged palpal organs (large dark disks) at the tip of the pedipalps and the spider's eight eyes when the image is expanded.
  1. ^ Chamberlin, R. V. & W. Ivie. 1935. The black widow spider and its varieties in the United States. Bull. Univ. Utah 25(8): 1-29. [15, f. 1, 4, 6-14, 21, 23-33]
  2. ^ Andrade, Maydianne C. B. (1996). "Sexual Selection for Male Sacrifice in the Australian Redback Spider". Science. 271 (5245): 70–2. doi:10.1126/science.271.5245.70. Retrieved 2007-01-15.  Unknown parameter |month= ignored (help)
  3. ^ "Black Widow Spiders". Hastings Reserve. 
  4. ^ Blackledge, Todd; et al. "Quasistatic and continuous dynamic characterization of the mechanical properties of silk from the cobweb of the black widow spider Latrodectus hesperus, table 1". The Company of Biologists. Retrieved 2009-01-23. 
  • Minus, A. 2001. "Latrodectus hesperus" (On-line), Animal Diversity Web. Accessed March 08, 2009
  • Platnick, N. I. 2008. Theridiidae The World Spider Catalog, version 9.0. American Museum of Natural History.

External links

Data related to Latrodectus hesperus at Wikispecies