Old World Swallowtail (Papilio machaon) (Linnaeus, 1758)
Diagnosis: The Papilio machaon group of swallowtails is one of the most complex groups of butterflies in North America. Over the years, definitions of species, subspecies and forms have varied widely. Some specialists, e.g., Scott (1986) and Sperling (1987), have tended to place a number of former "species" (i.e., oregonius, dodi and bairdii) under machaon. We have followed their taxonomic treatments. In Canada, all forms of the Old World Swallowtail are mainly yellow, closely resembling Anise Swallowtail (P. zelicaon). In all forms, machaon can usually be identified by the eye-spot on the hindwing upperside, in which the black pupil touches the abdominal wing margin. Wingspan: 51 to 95 mm.
Subspecies: The nominate subspecies occurs in the Old World. Recent works have placed six subspecies under Papilio machaon in Canada: the small subspecies aliaska occurs in Alaska, Yukon,the Northwest Territories, and northern British Columbia; subspecies hudsonianus is in Nunavut, the northern Prairie Provinces, northern Ontario, and into extreme northwestern Quebec; subspecies oregonius, which is larger and paler yellow, occurs in dry areas in southern British Columbia; subspecies dodi is found in badland regions of Alberta and Saskatchewan; subspecies bairdii, occurring mainly in the U.S., occurs in southern Saskatchewan, with a few records in Manitoba and Alberta; and the recently described subspecies pikei occurs in the Peace River area of Alberta and adjacent British Columbia.
Range: This species is found around the Northern Hemisphere. In Canada it occurs from the Arctic coast of Yukon, Nunavut and the Northwest Territories south through British Columbia (except the coastal regions) and east through the Prairie Provinces and northern Ontario to northwestern Quebec.
Early Stages: Larvae are similar to those of the Black Swallowtail (P. polyxenes) and feed on a wide variety of members of the parsley family (Apiaceae) in most of Eurasia. In Siberia and North America they feed on Asteraceae (= Compositae). Subspecies aliaska feeds on Artemisia arctica; subspecies oregonius, dodi, pikei, and bairdii feed on Dragonwort (Artemisia dracunculus). Subspecies hudsonianus is more uncertain, but there are several records on coltsfoot (Petasites spp.), in the Asteraceae but also on Scotch Lovage (Ligusticum scoticum) in the Apiaceae. Hybrid specimens between machaon and polyxenes in southern Manitoba (formerly known as Papilio kahli) feed on Meadow Parsnip (Zizia aptera), as do hybrids between machaon and Anise Swallowtail (P. zelicaon) in central and western Alberta (Sperling, 1987).
Abundance: This varies with subspecies; in most areas it is uncommon, but it can be locally common.
Flight Season: The different subspecies have different flight times. The earliest are subspecies oregonius and dodi, which fly in hotter, drier habitats, such as badlands, from May into July and again in August and September. Subspecies bairdii has a single flight season in July and August in the southern Prairies. The three northern subspecies are found as adults from late May into July in their subarctic, boreal, and northern prairie habitats.
Habits: In all of its widely differing habitats, this species can most easily be found on exposed hilltops or at cliff tops. The males patrol these areas to establish dominance while waiting for females to come up from lower down in nearby valleys to mate. It is possible to see a dozen or more males competing for space at a favoured hilltop.
© 2002. This material is reproduced with permission from The Butterflies of Canada by Ross A. Layberry, Peter W. Hall, and J. Donald Lafontaine. University of Toronto Press; 1998. Specimen photos courtesy of John T. Fowler.
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