The most invasive spiders in California are the brown widow spider, the black widow spider the desert recluse. These spiders are large and very noticeable, so if you have one in your home, you will definitely notice. These spiders thrive in warm climates, which is why they have spread throughout California.
The Brown Widow Spider
The brown widow spider was first found in California in 2000. Today, the species is common throughout Central and Southern California. The brown widow is originally from Africa although it does have established populations in parts of Australia, Japan and some Caribbean Islands.
The brown widow is a combination of tan and brown colors along with black accents. Its bite is very minor in comparison to that of a black widow, although humans can still experience painful symptoms. Headaches and nausea are very common if bitten by this spider, and some people need to be hospitalized because they lose consciousness.
...