Noble False Widow Spiders Were Absent From The United States Until A Specimen Was Found In Ventura County Nearly A Decade Ago

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Several frightening looking spider species can be found in southern California, such as western black widows, brown widows, desert recluses and several wolf spider and tarantula species. Many residents may know that the brown widow is a fairly new addition to southern California, as this species is not native to the US. However, few people are aware that a spider species commonly known as the noble false widow was found in Ventura County for the first time in history back in 2011. Not only was this the first time that a noble false widow had been found in California, but it was also the first time that a noble false widow had been found anywhere in the western hemisphere. While bites from the noble false widow are not usually dangerous, some medical case reports describe noble false widow bites as causing necrotic wounds. Therefore, the false widow is categorized as a species of moderate medical importance in the US.

In 2011, a group of experts were searching sparsely populated areas in Ventura County for the invasive brown widow spider species. Instead of finding brown widow specimens, the group came across several spider specimens that they did not recognize as being a part of southern California’s spider fauna. After capturing several specimens the group brought them back to a laboratory for identification. Much to the group’s surprise, the specimens turned out to be a species that is native to England and western Europe. The name of this species is Steatoda nobilis, but it is more commonly known as the “noble false widow” or the “European spider.” Since this discovery, the false widow has been found many times with several California counties including Monterey, San Diego, Alameda and Ventura Counties. The false widow is known for proliferating quickly in regions where it is not native, and it is believed that the species was accidentally transported to the Ft. Hueneme Naval Base by soldiers or other military officials. In most cases, the false widow’s bite will cause moderate to severe pain lasting 24 to 48 hours, but several case reports describe more pronounced symptoms, such as intense itching, swelling and minor necrosis around the bite wound. The noble false widow is considered the only spider species of medical significance in its native England, but no known deaths have resulted from this species’ bite.

Have you ever spotted a black widow or brown widow before?