We spread our wings and fly into Pollinator Week with these exquisite Old World swallowtail butterflies who are enjoying a sip of nectar. The gorgeous swallowtail is welcome in any garden, both for its beauty and its ability to pass pollen from flower to flower. Far less desired are swallowtails in their caterpillar form, which can take a toll on ornamental plants or citrus crops. There are more than 550 swallowtail butterfly species, and their name comes from the forked appearance of their hindwings, which can be seen when the butterfly is resting with its wings spread.