I set up Butterfly bushes last year to attract feeders. That particular species of plant (or numerous species) did a terrific job luring various types of butterfly and bee. I won't harvest bees for mantis food (as we all know, something's up with the honeybee population), but captured lots of Silver Spotted Skipper (Epargyreus clarus) butterflies, a fairly small species which my mantids loved. Picture below. Even though Monarchs and Tiger Swallowtails are far from endangered, I find them too large for most of my pets.
This is the type of plant I bought (most larger nurseries carry them) which worked so well: