I know this might appear to be a rediculous question, but it seems a little odd that a creature with compound eyes on the sides of it's head would have to turn its face directly towards an object to see it. I know this is an action that's generally associated with predators, in order to focus on pray, but the eyes of a mantis have neither the structure nor position of say, those of a wolf or a cat. And I never see other insects doing this, predators or otherwise.

Also, exactly why is it that a praying mantis' eyes darken when deprived of light, when again this is not something (at least as far as I have seen, and believe me, I spent the better part of my life catching and observing insects) that appears to be common in insects.