An initiative of Earthwatch Institute

  1. 157 Photo by Geoff Walker
  2. 157_0 Photo by Geoff Walker
  3. 157_1 Photo by Geoff Walker
  4. Papilio_anactus_caterpillar_-_donald_hobern Dainty Swallowtail caterpillar photo by Daniel Hobern
  5. Papilio_anactus_-_donald_hobern >2 cm caterpillar photo by Donald Hobern

Dainty Swallowtail Butterfly

Papilio anactus


  • Colour: the caterpillar (larva) is initially dark in colour with broad yellow-orange bands running across its body, and two rows of black spines running down its back. Its head is black and smooth. As it matures its body becomes blue-black. Just before becoming a pupa it turns dark green with orange-yellow blotches on its back and some small scattered pale blue-and-white spots. The butterfly (adult) has black wings covered with white-grey patches, and red-and-blue patches on its hindwing (back wing). The back edge of its hindwing is scalloped and the tip of its body is yellow.
  • Size: the caterpillar is up to 4 cm long; the butterfly has a wingspan of about 7 cm.


  • Diet: the caterpillar eats the leaves and soft new growth of native and introduced plants from the Family Rutaceae, particularly citrus trees; it will also occasionally eat the flowers and buds. The butterfly feeds on nectar from a variety of flowers, usually feeding while on the wing (like a hummingbird).
  • Movement: if disturbed, the caterpillar reveals a red-orange “tentacle” (known as an osmeterium) from behind its head which emits a foul smell to deter predators.
  • Flight: usually slow and lazy, although it can take off with great speed if disturbed. It is usually seen in low numbers and seldom stops or rests. Male butterflies strenuously defend their territory; they frequently spiral into the tree canopy in groups of two or three, before separating to descend.
  • Breeding: females lay cream-coloured eggs on the young shoots and leaves of the host plant, and the eggs usually hatch three to four days later. Once the caterpillar is fully developed, it forms into a green or grey-brown pupa attached to a stem of the host plant. The time it remains a pupa varies from about two weeks in summer, to four weeks in autumn, but often those formed in autumn will stay dormant over winter, emerging as butterflies in spring. It flies during the warmer months and there are continuous broods during this period.

What to Observe

  • Presence (to establish the first and last sighting for the season)
  • Courting/mating
  • Egg laying
  • Chrysalis (butterfly emerging from its shell)

ClimateWatch Science Advisor

We expect butterflies to appear earlier in the year as a result of climate change warming the Earth. They may also start appearing in new areas as warmer temperatures enable them to live in environments that were previously too cold for them.

When To Look

  • In the warmer months, usually from October through to May; however, the flying season can be longer in warmer areas such as Queensland.

Note: ClimateWatch is looking for any changes in the timing of these events so remember to keep a lookout from September and even earlier in warmer areas!

Where To Look

  • In open forests, woodlands and urban areas, particularly near citrus orchards.
  • All over Australia, but it is more common in the eastern states from north Queensland south to Victoria and across to the Flinders Ranges in South Australia. Its range is spreading due to the expansion of citrus orchards and it can now be found in most areas where these trees are cultivated.
  • Look on the leaves of citrus plants (for example limes, lemons, mandarins, oranges) for caterpillars, and around flowers for butterflies. Male butterflies commonly collect on hilltops and can be seen flying about head-height or spiralling up into the tree canopy.

Note: ClimateWatch is looking for any changes outside of their known ranges so remember to keep a lookout anywhere in Australia!

Dainty Swallowtail Butterfly distribution map - GBIF

Dainty Swallowtail Butterfly distribution map - GBIF

Where To Look

Maps of Habitat Suitability


Current probability
of occurrence
2070 probability
of occurrence (RCP 8.5)
Species range change from
current to 2070 probability

Above, the left and middle maps show the modelled habitat suitability for the the species under current and potential future climate conditions. The colours indicate the predicted habitat suitability from low (white) to high (dark red).

The future habitat suitability is modelled for the year 2070 under a climate change scenario that represents 'business as usual' (RCP 8.5). The map on the right shows how the range of the species might change between now and 2070, with orange areas indicating where the species might disappear, green areas where the species range might expand, and blue areas where the habitat is predicted to be suitable for the species now and in the future.

The models for this species were run in the Biodiversity and Climate Change Virtual Laboratory. Please note that while models can be very informative, they are only a representation of the real world and thus should always be viewed with caution. You can read more about the science behind these models here.



  • Walther G, Post E, Convey P, Menzel A, Parmesan C, Beebee TJC, Fromentin J, Hoegh-Guldberg O, and Bairlein F 2002. Ecological responses to recent climate change. Nature 416: 389–395.

More information:

  • Braby MF 2000. Butterflies of Australia: Their Identification, Biology and Distribution. CSIRO Publishing.
  • Common IFB and Waterhouse, DF 1981. Butterflies of Australia (revised edition). Angus & Robertson.

  1. Search Species

  1. What Else?

    • Orchard or Citrus Swallowtail Butterfly: caterpillar is larger (up to 6 cm long) and lighter green in colour with some pale yellow and brown markings. The butterfly is also larger (10­–12 cm wingspan) and only the male has black wings, with an arc of creamy-white spots near the tip of each forewing, but not patches over its entire black forewing like the Dainty Swallowtail.
    • Clearwing or Greasy Swallowtail Butterfly: its forewing is transparent with one or more black spots.
  1. Did You Know?

    It belongs to a group of swallowtails that all look like other poisonous or foul-tasting butterflies to deter predators.

    It is the smallest swallowtail butterfly in Australia.

    Eggs can sometimes hatch after one day if the female has been holding on to them for a long period after they have been fertilised.

    It can take as little as five or six weeks for an egg to develop into a butterfly.

    During its life, a caterpillar eats the equivalent of about two adult leaves of a grapefruit tree, or three leaves of a lemon or orange tree!