I live in central CA. Some of the blackberry bushes here have spiders I've never seen except in the blackberry bushes. They have every combination of warning colors you can imagine and spin small,carpet-like webs about 2-3" or so with no tunnels or trip wires. When you touch the web,they bail out and fall to the ground. I've never seen such dangerous looking spiders abandon ship so readily. They almost seem to faint.What kind of spiders could these be?