Help - something is eating my stems!

[soozbz]

Hi, all! Something is taking gigantic chunks out of my tomato stems and totally destroying them. See attached photos. I've never seen anything like it!

Does anyone know who the culprit might be? I've picked a few brown caterpillars off of these plants, but I've never seen a caterpillar do this to a stem. I've also got squirrels and birds around who like to steal my tomatoes, but I've never seen them take in interest in stems, either.

In addition, any thoughts on how I can save plants whose stems have been devoured? Can I wrap them with something, or should I just leave them be and hope for the best?