The black widow spider is known and feared by many people due to its venomous bite. However, in the past decade in California, a change in widow spider populations has occurred. A newer invasive spider called the brown widow may be displacing black widow spiders in some urban habitats.
Underside of adult black widow spider. [J.K.Clark]
Brown widow spiders are now common in urban areas of Los Angeles, Orange, San Diego, Riverside, San Diego and San Bernardino counties. People have also reported finding them in Ventura and Santa Barbara, and experts believe they may eventually be found in other areas of the state.
Residents may be relieved to learn that brown widow spiders are less likely to bite and if they do, the symptoms are more mild than a black widow bite.
Mature female brown widow spider. [R.S. Vetter]
You can read more about widow spiders in California in the newly updated Widow Spiders and Their Relatives Pest Note, byRick S. Vetter, which was previously titled Black Widow and Other Widow Spiders.