Species Steatoda nobilis

"Noble False Widow"

"False Widow" (not to be confused with Steatoda grossa or any of the other Steatoda that occasionally go by the same common name)

Author of the name: Thorell. Year first published: 1875, as Lithyphantes nobilis.

Body length of adult male 7.8—10.6 millimeters.(1)

Body length of adult female 9.5—14 millimeters.(1)

Adult female:

Adult male:

Introduced to California from Europe, possibly via the naval base at Port Hueneme, CA.(2) It is native to Madeira and the Canary Islands, but spread to Great Britain, Portugal to Italy, and Algeria so far. At the time of publication of Vetter & Rust's 2012 paper, it had only been officially collected from Ventura County, California. However, since then, BugGuide records indicate that it is also living in at least Orange, Alameda, Monterey, and Santa Clara counties.

Usually found on structures.

Unlike most cobweb spiders, which build a tangled, haphazard web, Snazell & Jones (1993) report that this species builds a well-developed funnel-shaped web, as in some of the agelenids. One can tell the difference because the S. nobilis web is made of unusually strong silk. It reportedly takes a few days for them to finish their full funnel web so, in the beginning stages, it does look like a normal cobweb.(1)

The epigynum of the female (at least in scientific diagrams) looks very similar to the native Steatoda palomara. It appears that the palp of the males are more easily separated. Steatoda nobilis is also larger than S. palomara.

—Kulczycki, A., C. M. Legittimo, E. Simeon & P. Di Pompeo. 2012. "New records of Steatoda nobilis (Thorell, 1875) (Araneae, Theridiidae), an introduced species on the Italian mainland and in Sardinia." Bull. Br. arachnol. Soc. 15: 269-272.

—Roberts, M. J. 1995. Collins Field Guide: Spiders of Britain & Northern Europe. HarperCollins, London, 383 pp.