Desert swallowtail caterpillars feeding on fennel; an outstanding lab substititue for any machaon group swallowtail.  In other words, if you grow fennel in your yard, you then can raise anise swallowtails (Papilio zelicaon), baird's swallowtails (Papilio machaon bairdi), eastern black swallowtails (Papilio polyxenes asterius), short-tailed swallowtails (Papilio brevicauda), and ozark swallowtails (Papilio joanae.)