INVASIVE SPECIES: Zoropsis spinimana
  Zoropsis spinimana
  This exotic spider was recently introduced to California from the Mediterranean region. It is the first member of the Zoropsidae family to be recorded in the United States, bringing the total number of spider families in the country to 68. Photo: Charles Griswold, CAS

A species is considered invasive when it has been introduced by humans and it competes with or displaces native species.

These large spiders are currently invading the San Francisco area. Native to the Mediterranean region, the colonizing spiders or egg sacs probably traveled to the Bay Area with a furniture shipment or in a vacationer’s suitcase. Academy scientist Darrell Ubick was the first to recognize Zoropsis spinimana as an alien species. He is currently tracking its spread from the South Bay – so far, it has been documented in five cities, both in nurseries and in homes. Ubick and Academy colleague Charles Griswold recently published a scientific paper announcing its arrival. It is the first representative of the large Zoropsidae spider family to be found in North America.