Papilio machaon, the Old World swallowtail, is a butterfly of the family Papilionidae. The butterfly is also known as the common yellow swallowtail or simply the swallowtail (a common name applied to all members of the family, but this species was the first to be given the name). It is the type species of the genus Papilio. This widespread species is found in much of the Palearctic (it is the only swallowtail in most of Europe) and in North America.
This species is named after Machaon (Ancient Greek: Μαχάων, romanized: Makháōn) a figure in Greek mythology. He was a son of Asclepius in the works of Homer.
Papilio machaon was named by Carl Linnaeus in the 10th edition of Systema Naturae in 1758, alongside nearly 200 other species of butterfly. Later, Pierre André Latreille designated it as the type species of the genus Papilio.
Papilio machaon gorganus is strongly migratory in Europe and may be found in almost all habitats. In the UK, P. m. britannicus is an endemic subspecies, but occasionally individuals of the continental subspecies P. m. gorganus breed temporarily on the south coast. Subspecies P. m. britannicus differs from the continental subspecies in being more heavily marked in black. The Maltese Islands are home to another endemic subspecies, P. m. melitensis
This butterfly is present throughout the entire Palearctic region, ranging from Russia to China and Japan, (including the Himalayas and Taiwan), and across into Alaska, Canada, and the United States, and thus, is not restricted to the Old World, despite the common name. In Asia, it is reported as far south as Saudi Arabia, Oman, the high mountains of Yemen, Lebanon, Iran and Israel. In southern Asia, it occurs in Pakistan and Kashmir, northern India (Sikkim, to Assam, and Arunachal Pradesh), Nepal, Bhutan, and northern Myanmar.
This butterfly is widespread in Europe. In the United Kingdom, it is limited to a few areas in the Norfolk Broads of East Anglia. It is the UK's largest resident butterfly. The monarch (Danaus plexippus) is slightly larger, but is only a rare vagrant.
As P. machaon is widespread throughout Eurasia and often common, it is not threatened as a species. It is listed as "vulnerable" in the South Korean and Austrian Red Data Books, and in the Red Data Book of the former Soviet Union. In Armenia the species demonstrates stable population trend and is assessed as Least Concern.
In some countries, P. machaon and its subspecies are protected by law. Papilio machaon machaon is protected by law in six provinces of Austria, Czech Republic, Slovakia, Hungary, Romania, and Moldova. The species is protected in the United Kingdom, and subspecies verityi is protected in India.
In late 2017, P. machaon was among several species of butterflies selected by the Estonian Society of Lepidopterists as contenders for the National Butterfly of Estonia. Nearly 5,000 members of the public voted online, with P. machaon receiving 2,664 votes, overwhelmingly winning the title. As well as becoming the National Butterfly of Estonia, P. machaon was named as the Butterfly of the Year for 2018; an honorary title given to a native butterfly species in Estonia annually.
