We, of course, sought our answer from one of our most favorite books: Tracks and Signs of Insects and Other Invertebrates by Charley Eiseman and Noah Charney and discovered these cut circles are the work of Leafcutter Bees (Megachilidae). Perfect name!
From Eiseman's and Charney's book: "They cut both circular and oval pieces from the edges of leaves, which they use to make cells in their nests. The bee first forces several circular pieces into the bottom of a burrow to form the base of a cell, lines the sides with several oblong pieces, and then packs in several more circular pieces to close the cell, creating a thimblelike capsule."
We are amazed. These cut pieces of leaves become the protective home of baby bees. So, so cool. What might it be like in one of those cells?
You can find so many more stories like this one on Charley Eiseman's blog.
