Papilio Machaon: Old World Swallowtail Butterfly

The Old world swallowtail, also known as Papilio machaon gorganus and Common yellow swallowtail, is present around Europe, Asia, and North America and is known for its bright yellow base, black veins on wings, and red eyespots close to its tails.

Papilio Machaon Species summary

Scientific NamePapilio machaon
Family NamePapilionidae
Kingdom Animalia
Genus Papilio
HabitatOpen hilltops, mountain meadows, and tundra
Host PlantsSagebrushes (Artemisia species)
Butterfly DescriptionYellow wings with black veins and tails
Caterpillar DescriptionYoung caterpillars look like bird droppings, older instars are green

Butterfly Physical Description

Papilio Machaon
Papilio Machaon

Papilio machaon has a wingspan of 2 1/2 to 3 inches (6.5 to 7.5 cm). The upperside of its hindwings has a reddish eyespot close to the tail. There’s also a black area near the lower border of the inner edge of the hindwing. These eyespots aren’t centered.

Adults usually have yellow wings with black veins. Both males and females have a pair of protruding tails and 1 red and 6 blue eyespots below.

When they’re closed, the wings are mostly white, with a faint impression of the veins similar to the dorsal side. The ventral side of the wings also has 2 orange marks on the lower section of the hindwings.

Common subspecies comparison

Algerian species, Papilio saharaeHave a variation in the segments of antennae
Papilio hospitonLives in Corsica and Sardinia, has thicker but shorter tails on its hindwings
Papilio machaon BritannicusHas more rounded tails, the most similar to Old world
Papilio machaon bairdiiMostly black, with 1 row of white spots on the edges of its forewings and 1 row of bluish and white spots on its hindwings
Papilio machaon hippocratesAlso similar to Old world, with longer tails

Papilio Machaon Caterpillar Description

Papilio Machaon Caterpillar
Papilio Machaon Caterpillar

The larval stage of Papilio machaon is around 1.8 inches (4.5 cm). Young caterpillar resembles a bird dropping, which it uses for camouflage.

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Later instars are green with black and orange markings. If disturbed, this caterpillar releases a foul smell, but it’s only effective against insects, not avian species.

Larvae are quite fast eaters. They spend most of their time eating or resting. Once grown enough, they’ll attach themselves to any nearby plant using their silky threads and stay like that until they turn into pupa – for about a day.

Papilio Machaon pupa stage description

Once they get into the pupa stage, you can carefully pick them up and place them in a warm location. The temperature will determine how long it takes to switch to the chrysalis. If it’s kept in summer temperatures, it will take up to 2 weeks. If the temperature is lower, the process might last several months.

Some species will pupate and emerge in the same year. These are known as univoltine kinds. Others will overwinter as pupae and emerge the following year, being bivoltine.

How did this butterfly got its name?

Carl Linnaeus names Papilio machaon after an ancient Greek mythological figure. Linnaeus used the name of Asclepius’ son.

Usual Papilio Machaon Distribution

Papilio machaon is present around the Holarctic. It’s common in North America (South Alaska) and Canada, especially British Columbia. The sightings include several parts of Asia, such as Russia, China, Japan, Nepal, Bhutan, and Myanmar. Other locations include:

  • Iran
  • Israel
  • Lebanon
  • Saudi Arabia
  • Yemen

Is Papilio Machaon the largest butterfly in the UK?

This butterfly is also present in Europe. In the UK it’s limited to Norfolk Broads of East Anglia and is considered the largest butterfly in the country. 

Ideal Habitat

Old world swallowtail likes open hilltops, mountain meadows, and tundra. This butterfly also loves sunny lands and gardens. Chances are you will see it flying around your yard since it’s so common. The British subspecies, P. m. Britannicus stays around the fenland habitat.

Usual Host Plants

Female Old world swallowtails go for sagebrushes (Artemisia species):

  • Arctic wormwood
  • Wild tarragon

What does Papilio machaon eat?

Caterpillar food plants are as listed above, including milk parsley (especially for the British subspecies). Adults feed on flower nectar. Food plants of European, Asian, and North American species vary and include:

  • Wild carrot (Daucus carota)
  • Wild angelica
  • Fennel (Foeniculum vulgare)
  • Hogweeds (Heracleum)

This butterfly has great adaptability, and in some locations, it will feed on Compositae, while in others, it will go for Rutaceae or Umbelliferae.

Old World swallowtail Behavior

Old world swallowtail has a strong and fast flight. Still, it will frequently pause over herbs to sip nectar. Males are “hilltopping” – congregating near summits to compete for females. Butterflies living in the north will have one flight in late May/July.

Those living in the south will have 2 flights, and their flights also seem to be affected by elevation. Butterflies that live in lower elevations fly from March to September, and those in higher are around during short summers.

Females lay eggs on the host plant one by one, having 2 broods annually. Older caterpillars eat the flowers of the plants belonging to the parsley family. Chrysalids overwinter. The total lifespan varies between the subspecies, but the general life expectancy is about a month.

Common Predators

Like many other butterflies, Papilio machaon falls prey to:

  • Spiders
  • Lizards
  • Small mammals
  • Birds
  • Various insects

Locations where this butterfly is protected

Old world swallowtail is listed as vulnerable in South Korea and protected in Malta. The butterfly and its subspecies are also protected in:

  • Austria
  • Czech Republic
  • Hungary
  • Moldova
  • Romania
  • Slovakia

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