Adult red-spotted purples are thought to mimic pipevine swallowtails, and they can be difficult to separate from any dark swallowtails if seen in flight at a distance. Note the lack of tails, the black lines near the hindwing margin dorsal view (seen from above), and the red-orange spots on the underside (ventral side) of the wings. No swallowtails have ventral red-orange spots near the body.
The larvae mimic bird droppings. They are humped at the thorax and covered with numerous tubercles, with one longer pair on the thorax. Body color is mottled shades of brown, brownish yellow, white, and green.
Wingspan: 2¼–3½ inches.
Habitat and Conservation
Found in and near woods, parks, and suburban neighborhoods. Adults frequently sit on trees and shrubs, slowly opening and closing their wings. They are often seen at mud puddles and damp places along creek beds, where they take moisture from the damp ground.
Larvae feed on a the foliage of a wide variety of deciduous trees and shrubs, including willows, wild cherry, apple, and crab apple. The adults visit flowers, but they prefer to absorb moisture and nutrients from puddles, damp ground, decaying fruit, and animal droppings.
Common breeding resident. Taxonomically, our "red-spotted purple" form of this species used to be considered a separate subspecies (astyanax) from the other forms of this widespread North American butterfly. Elsewhere on the continent, at least two other forms (often called "white admirals") are a lot like our butterfly, but have the addition of a broad white band running across the middle of all the wings, both above and below. These different races interbreed in areas where their populations overlap, and their offspring often show a blend of characteristics.
Adults fly from May into October. Partially grown caterpillars hibernate through winter sheltered in a rolled leaf that is spun into a tube and secured to the twig with silk. During hibernation, the caterpillar’s breathing and metabolic rate slow; its blood thickens, and the percentage of water in the body drops from 80 percent to 55 percent to prevent freezing damage.
Although the spots are really orange and not red, and blue is more prominent than the subtle violet hues, the red-spotted purple is a stunning sight, evoking awe and appreciation.
The lookalike pipevine swallowtail is toxic to its would-be predators. The red-spotted purple is palatable but has a color pattern that mimics the toxic species. Predators avoid both of them on sight. The larvae also use coloration to avoid being eaten — they resemble unappetizing bird droppings!