I can only comment on my neighborhood in the south SF bay area. Given that the region is a former home to orchards it doesn't surprise me that there is a lack of insects, but given the amount of trees/greenery vs my old SoCal neighborhood I can say that there is a startling lack of bugs here, with the exception of cockroaches(several varieties are disturbingly plentiful on the sidewalks at night), isopods/woodlice/pill bugs, and black widow spiders. Going on hikes in the Santa Cruz mountains, it also seemed like there were a shortage of insect life compared to hikes in SoCal.