yep, mantis eat mainly the larger bugs, like flies / grasshoppers / bees / moths/ butterflies / spiders / etc.
so, not effective for caterpillars. + mantis will not go digging through your buds to find bugs to eat, they don't have the ability to do so (do not burrow). They wait for prey to pass by.
Ladybugs go in hibernation and fly away into the mountains or huddle in a nest with a bunch of other ladybugs (I think in the Fall?), so not very effective either.
To the guy saying no money for BT, better get on that shit, it's only $10 for a small bottle. Caterpillars are no joke and will destroy your plant faster than you know it. You may think there's only 1 or 2, but realistically do you think a moth / butterfly is only going to lay 2 eggs? Most of them are tiny and hiding inside the buds or burrowed into the stems already.