Communication doesn't require sentience. You don't need to be able to sense the environment to say "I'm being eaten by bugs!", you just need to be able to sense

Communication doesn't require sentience. You don't need to be able to sense the environment to say "I'm being eaten by bugs!", you just need to be able to sense your own body. On the other hand, the ability to move is pretty much required for sentience. The organism needs to be able to avoid harmful stimuli and seek out beneficial ones to be considered sentient. Just releasing chemicals or signals isn't enough.