Promethea Moth

Callosamia promethea — the promethea moth — is one of about 4 species in genus Callosamia (the 'silk moths') and one of the most-studied giant silk moths in eastern North America. The species is widespread across the eastern US from southern New England south through the eastern US to northern Florida and west to the Great Plains. Adults are 7-10 cm wingspan with one of the most striking GENDER DICHROMATISMS in Saturniidae: FEMALES are large warm REDDISH-BROWN moths with cream-and-tan wing markings (the typical 'giant silk moth' coloration), while MALES are dramatically DARKER — almost completely black with only thin tan-and-cream wing borders and a characteristic crescent-shaped pale spot on each wing. The two sexes look so different that early entomologists initially classified them as separate species. The species is also remarkable for FLIGHT TIMING DIMORPHISM. Most giant silk moths (luna, cecropia, polyphemus, regal, imperial) are strictly nocturnal — both sexes fly at night. Promethea moths split: FEMALES fly at night (typical Saturniidae), but MALES fly in the LATE AFTERNOON (3-7 PM) seeking females through pheromone tracking. The day-flying dark males are widely interpreted as BATESIAN MIMICS of the toxic pipevine swallowtail butterfly (Battus philenor) — the dark coloration, day-flying behavior, and rapid flight closely match the pipevine, joining the same mimicry complex that includes spicebush swallowtails (Papilio troilus), black-form female tiger swallowtails (Papilio glaucus), red-spotted purples (Limenitis arthemis astyanax), and other dark eastern US lepidoptera. The cross-order mimicry (a moth mimicking a butterfly) is one of the most-cited examples in mimicry biology of how mimicry pressure can drive convergent evolution across very different taxonomic groups. Larvae are pale blue-green caterpillars with rows of red-and-yellow tubercles, feeding on a wide range of host trees including spicebush, sassafras, tulip tree, ash, and lilac. Pupation occurs in a remarkable cocoon — the larva uses leaves of the host plant to construct a brown silk-and-leaf cocoon that hangs from the host tree branch by a silk stalk through winter (the cocoon often persists on the host tree visible all winter). Adults do not feed. The species is harmless to humans.