I think now that the gauges are sometimes missleading. I've been running a new sim through the night (on my new computer, still running the same evosim on my old one) and I found a bot with a yellow circle in it, but when I checked out it's values in the robot info they were all 0.
Also I think it's strange that two bots with the same gene can behave different, one had all 0 values while another one had a lot of buildup of shell, venom and so on. I thought they needed genetic instructions to be able to do that. The same goes with bots suddenly turn cancerous despite they have the same genes as bots that DON'T turn cancerous.