Answer: That does sound like a sign of some insect, but it's difficult to say what it might be. I suggest you continue monitoring the leaves--look carefully underneath and on stems in the area where the black spots are and you should be able to find the culprit. You might want to try using a magnifying glass and check at night for nighttime eaters. When you find the insect, send another question to the Q&A site (not my email address) with its description, as well as a description of the damage to the leaves. Then we can suggest an appropriate control. Good luck!
Q&A Library Searching Tips