Question: I have noticed that when a cockroach dies it first turn over on its back.  Can you please tell me why cockroaches do this?

ANSWER  I think it depends on what the roach was exposed to. Many (but not all) of the modern insecticides cause this. It may be due to the effect on the nervous system of the roach.  There have been other types of products that caused the roach to stop in its tracks and die standing up.