When you see a caterpillar on dill in your garden—or other plants—you may be startled, grossed out, or annoyed that your plant is being systematically decimated. I get excited. Because I know it’s a black swallowtail caterpillar (Papilio polyxenes) that’s going to turn into a beautiful butterfly. And that butterfly is going to become one of many valuable pollinators in my garden. I see a few types of swallowtail butterflies fluttering about my property, landing on various annuals and perennials. They are am