I read the advice about caterpillars on herbs but usually the caterpillars on herbs are swallowtail caterpillars!
Swallowtails are plant specific, and in this case the question was in regard to basil and mint. The most common swallowtail in our area, the Black or Parsnip Swallowtail, is specific to plants in the Apiaceae family, i.e. carrot family, like parsley, fennel, carrots, etc. There are many other swallowtails, but none I find that feast on basil and mints. Their caterpillars are quite distinctive also. But I applaud the reader for considering the welfare of butterfly caterpillars. - Carole