Cocoons! (part 1)

Just took a look a few minutes ago and have discovered that a couple of silkworms have settled down to work...



Already they have eaten their last meal. Soon, whatever they were, will be changed into something else: pupae, and then into mouthless moths. Are they still the same individuals? If we could change from one thing to another - would we still be the same being?

Then, after they become moths, they will live only enough days to mate and for the female to lay eggs. Why are they programmed to self-destruct in this way? What if we knew exactly how long we were to live - to the day?

As usual, the more I find out, the more I need to find out.