European Spider


European Spider, Steatoda nobilis Theridiidae

The Situation: In 2011 in Ventura County, while searching for the non-native and invasive brown widow spider, Latrodectus geometricus, a discovery was made of a large brown spider that was not recognized as being part of the southern California spider fauna. Several specimens were collected and brought back to the lab for identification. They turned out to be a European spider, Steatoda nobilis, which is the first documentation of this spider in the Western Hemisphere.

Distribution: European Spider is known from England, Spain and other portions of western Europe. In California, it was collected in Monterey, San Diego, Alameda and Ventura counties. It can be very common where it is found. Speculation is that it might have been introduced into California via the U.S. Naval base in Port Hueneme.

Identification: There are many spiders of the genus Steatoda in California but none get as large as S. nobilis. Previously the largest Steatoda in California was the false black widow, S. grossa, which is slightly smaller than a mature black widow, is chocolate brown or dark plum in color and may have a small white or tan band on the front surface of its abdomen. In contrast, S. nobilis is about the size of a mature black widow spider, and has a thick white or tan band on the front part of the abdomen and on the back in many specimens, is a white pattern that looks like a house with a domed or peaked roof pointing toward the front of the body, often with two dark “windows” in the body of the house (Figure 1). However, in some of the mature specimens, this house pattern is lost such that the only portion that is retained is the roof (Figure 2). Males are somewhat similar except that they have smaller abdomens and may have more white design on their bodies (Figure 3).

European Spider
Figure 1 (above). Immature of the false black widow, Steatoda grossa, showing the abdominal dots.  This is a common West Coast spider.  


European Spider
Figure 2 (above). Mature female of the false black widow, Steatoda grossa, showing a uniformly colored dark abdomen.  This is a common West Coast spider. 


European Spider
Figure 3 (above). Female of Steatoda nobilis showing significant abdominal coloration.


European Spider
Figure 4 (above). Female of Steatoda nobilis showing the remnant peak of the abdominal coloration.


European Spider
Figure 5 (above). Male of Steatoda nobilis. 




European Spider                
False Black Widow Spider
Steatoda nobilis    Steatoda grossa
Abdomen with houselike pattern on back   Abdomen usually all brown
If there is no large pattern on the back, there will be a small forward pointing white arrow near the front (fig. 4)   If there is a pattern on back, it will be rounded spots
Legs are reddish brown   Legs are brown


Damage: The spiders are large but there is only one recorded bite from England which had very minor effects. This spider IS NOT considered to have any significant venom toxicity.

This information was published in the following article:
Vetter, R. S., and M. K. Rust. 2012. A large European combfoot spider, Steatoda nobilis (Thorell 1875) (Araneae: Theridiidae), newly established in Ventura County, California. Pan-Pacific Entomologist 88:92-97.  Contact Rick Vetter for a a PDF.


Distribution of the European Spider in California




Center for Invasive Species Research, University of California Riverside 

Text and by: Richard S. Vetter, Department of Entomology, University of California Riverside
Photos by and Richard S. Vetter


Richard S. VetterStaff Research Associate 



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