You've got aphids! Congrats!
No, I'm really glad to know there are no caterpillars in distress. And honestly, when I was volunteering in the butterfly exhibit at the Museum of Science and Industry in Tampa, I had an older couple come in one day and ask if Monarch eggs were yellow and "if they moved". I politely told the couple they had aphids and then I showed them some of our milkweeds with both aphids and eggs. They were trying to help the Monarchs and I applaud anyone out there who is doing so!
The only stupid question is the one you don't ask!