Most likely nothing has "munched" on your fruit, but that the tree is simply doing what citrus do - set way more fruit than they can develop to maturity, and dropping the excess fruit. You'll see two fruit drop cycles, one at about BB size, and then a second drop at about pea size. Very normal, and young trees may drop all their fruit. This is to allow the tree to develop enough leaf canopy to actually support fruit development. Perfectly normal.

Patty S.

Here is a link that might be useful: UC IPM: Fruit Drop

Yep, they're at BB size right about now. Thanks so much for the info!