I've caught lot's of crappie on nightcrawlers, but it seems like they only want the butt end of the worm, about the last two inches of it. I've used meal worms for bait but only caught bluegill. I have a faint memory of putting some mealworms into a jar of cornmeal as a kid, and thinking they would breed into more mealworms, came back to check a few weeks later to find some moths in there. I think mealworms are some kinda moth larvae.