Pipevine Swallowtail

Battus philenor — the pipevine swallowtail — is one of the most spectacular dark-iridescent butterflies in eastern North America and the MODEL species of the most-cited mimicry complex in the region. Adults are 7-13 cm wingspan with dramatic black wings carrying brilliant iridescent blue scaling on the upperside hindwings (males much more intensely blue than females), bold orange spots in submarginal arrays, and the family-typical hindwing tail extensions. The species is genuinely chemically defended: caterpillars feed exclusively on pipevines (Aristolochia macrophylla, A. tomentosa, and other Aristolochia species) and sequester ARISTOLOCHIC ACIDS from the host plants. Aristolochic acids are potent renal-toxic alkaloids that cause severe vomiting and aversive learning in bird predators. Adults retain the compounds and are reliably bird-aversive — birds that try a pipevine swallowtail once vigorously avoid the species (and any visually-similar species) for the rest of their lives. The visual aposematism is so effective that the pipevine swallowtail is the model of one of the most extensive mimicry complexes in North American Lepidoptera. AT LEAST FIVE OTHER UNRELATED BUTTERFLY SPECIES converge on similar dark-with-iridescent-blue-and-orange-spots wing patterns to mimic the pipevine swallowtail: (1) the dark-form female of the eastern tiger swallowtail (Papilio glaucus); (2) the spicebush swallowtail (Papilio troilus); (3) the black swallowtail (Papilio polyxenes); (4) the red-spotted purple (Limenitis arthemis astyanax); and (5) the female Diana fritillary (Speyeria diana). Some of these mimics are themselves chemically defended (Müllerian mimicry); others are palatable and gain protection only through the mimicry (Batesian). The complex is one of the most-studied multi-species mimicry rings in North American Lepidoptera and is featured in essentially every introductory biology textbook discussion of mimicry in animals.