Frass?

I spotted these three piles of what looks like frass on a leaf. There may have been beetle larvae under the piles. The holes on the leaf look like they were made from tortoise beetles (Charidotella sexpunctata), so the frass may be from the beetles...There's a tiny, white thing next to the center frass pile that looks like it could be something...

Habitat: Calystegia sp. leaf in a rural garden