31-5-2017 MARJAL DE MOROS, VALENCIA - OLD WORLD SWALLOWTAIL BUTTERFLY (Papilio machaon)

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 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.

There are usually two to three broods in a year, but in northern areas, the species may be univoltine. In some places such as the UK, some will pupate and emerge in the same year and others will overwinter as pupae before emerging the following year, a situation known as being partially bivoltine.

The caterpillar spends the first part of its life with the appearance of a bird dropping, an effective defense against predators. As the caterpillar grows larger, it becomes green with black and orange markings. It has a defense against predators in the form of an osmeterium, which consists of retractable, fleshy projections behind its head that can release a foul smell if disturbed, which deters insects, but not birds.