The things roly-polys like is small seedlings. But wish I could help you if no one answers your ? try the hosta forum.
Jill

Sowbugs and/or pillbugs CAN cause damage to tender plants if their populations are very high. You might want to consider changing the environment around the hosta just a little, to discourage these little critters. Rake away the mulch for a while, which will remove their habitat, and make sure that you aren't watering too much. I'm not saying that these little animals are to blame here, but it would be a worthy effort to make things less hospitable.

Diatomaceous Earth (horticultural grade) can help control the population.

What does the damage look like, by the way? That can be a clue.

Sorry I'm just getting back to the computer...been in the yard for 4 days! Rhizo, the damage is nibbled edges (to the point that nothing is left but the stem on some of the plants.) and yes, I have had them heavily mulched. I'll try raking it back tomorrow. And I've never tried the diatomaceous Earth on anything before. Where do I get it?
Thanks for all your help!

That kind of damage doesn't really sound like sow-or pill-bugs to me. Hmmmmm. Anyway, DE can be found at most garden supply centers, including the big box stores. Just be sure to get the horticultural grade and not the stuff made for swimming pools.

DE works as a physical abrader. It get under the exoskeleton of insects and scratches them. They die by dessication. Apply it on top of the soil so that they come into contact with it. It doesn't dissolve. It should help get rid of some of those little roly polies.

Probably leaf cutter bees. These are the bees that bore into wood. They take bites of leaves and use them in the nests that are bored into wood. See the link below for info about these bees. Go to this link to see the question I posed on the Hallson hosta forum:

http://www.perennialnursery.com/forums/viewtopic.php?t=48227&highlight=leaf+cutter+bee

Here is a link that might be useful: Leaf Cutter Bees