Mantises are greatly beneficial in gardens and should be left alone to do their work. They eat a large volume of pest insects and can be a farmer/gardener's best friend in removing infestations of wasps and beetles. A Praying Mantis (or its eggs) can even be purchased in the spring to head off any pest growth come summer. Larger species of the Mantis family have even been known to eat frogs, lizards and sometimes even hummingbirds.
Females lay their flat, seed-shaped eggs on a twig in autumn. The freshly laid eggs are then coated with a hard foam that maintains moisture during dry winters and deters birds and other insects from bothering them as well. In spring, the eggs hatch and pale nymphs, shaped like miniature adults emerge and immediately begin feasting on smaller insects and sometimes each other.
Catching a glimpse of a Praying Mantis is a special thing, but leave it where you found it (if it hasn't flown away). It hunts all day long, feeding a king-size appetite. Capturing mantises to keep a as 'pet' will kill it. Mantises eat non-stop, all day long. People couldn't feed them as often as they would require in order to avoid starvation. Mantises do not 'look' hungry, but they always are. For the benefit of the ecosystem, simply look and leave them alone.