With a wing span often exceeding five inches, the giant swallowtail is one of the largest North American butterflies. Ranging throughout most of the U.S., the giant swallowtail is particularly abundant in the southern states where it is a common garden visitor. The giant swallowtail is at home in a wide variety of habitats including forest edges, agricultural farmland, dry pinelands, citrus groves and suburban gardens. The larvae feed on citrus-family plants such as prickly ash, hercules club, wild lime, hoptree, all kinds of citrus trees and rue (Ruta graveolens). The larvae occasionally become minor pests on commercial citrus crops.
Like most other swallowtail species, immature giant swallowtail larvae have a color pattern that resembles bird or lizard droppings. The larvae, called “orange dogs”, have a pair of foul-smelling bright orange “scent horns” that emerge from the body when disturbed. Once again living up to its name, a full grown giant swallowtail caterpillar may exceed two inches in length.