Graphium choredon (C. & R. Felder 1864)
Blue Triangle or Common Bluebottle
Don Herbison-Evans
Stella Crossley

Graphium choredon
early instar, magnified

The caterpillars of this species at first are dark grey and hairy, with a pale yellow tail. As they grow they become green with a humped thorax, tapering from the thorax rearward. The yellow tail develops into a pair of white spikes. Paired dark blue spikes also develop on each of the three thorax segments.

Graphium choredon
later instar
(Photo: courtesy of Rosemary Robins, Eureka, New South Wales)

The caterpillar is often found on the introduced

  • Camphor Laurel ( Cinnamomum camphora, LAURACEAE ),

    although its other food plants include Australian natives in LAURACEAE such as:

  • Blush Walnut ( Beilschmiedia obtusifolia ),
  • Oliver's Sassafras ( Cinnamomum oliveri ),
  • Three veined Cryptocarya ( Cryptocarya triplinervis ),
  • Steelbutt ( Endiandra impressicosta ),
  • Bolly ( Litsea reticulata ), and
  • White Bolly Gum ( Neolitsea dealbata ),

    as well as plants in other families such as

  • Grey Sassafras ( Doryphora aromatica, MONIMIACEAE ),
  • Glasswood ( Geijera salicifolia, RUTACEAE ),
  • Coondoo ( Planchonella laurifolia, SAPOTACEAE ).

    Graphium choredon
    (Photo: courtesy of Tim Waugh, Uki, New South Wales)

    The spikes on the metathorax become longer than the others, and connected by a conspicuous yellow bar. The sides of a mature caterpillar are marked by a whitish line just above the legs. The caterpillar grows to a length of about 3 cms.

    When it is disturbed, the caterpillar displays, often rearing up on its rear legs. It may also extrude a pair of pale translucent yellow or green fleshy horns (osmeterium).

    Graphium choredon
    later instar displaying
    (Photo: courtesy of the Macleay Museum, University of Sydney)

    The osmeterium comes from a dorsal pocket in the prothorax, just behind the head. The horns smell strongly of camphor, and are retracted quickly after a second or two.

    Graphium choredon
    (Photo: copyright Lyn Finn, Hunter Region School of Photography in Newcastle,
    Macquarie Hills, New South Wales)

    The caterpillar pupates on a leaf of the food plant. The pupa is green with a few yellow lines that converge to a spike on its head. The pupa is held by a silk girdle around the middle, and a cremaster at the tail. The colour of the pupa takes on the same shade as the leaf it is on.

    Graphium choredon
    showing colour of pupa takes on the colour of the leaf it is on
    (Photo: courtesy of Stewart Newman, Sydney, New South Wales)

    Within three weeks in summer, the adult emerges, having a wing span around 7 cms.

    Graphium choredon
    (Photo: courtesy of Rosemary Robins, Eureka, New South Wales)

    The wings are black above and brown below, with large turquoise patches in the middle of both fore and hind wings. These patches seem to form a triangle, with the apex pointing towards the body.

    Graphium choredon
    (Photo: courtesy of Todd Burrows, South Stradbroke Island)

    The underside of the wings are similarly marked with turquoise patches, and each hind wing has some red dots on its underside.

    Specimens reared in captivity are usually smaller and not as blue as wild forms. The reason for this is unclear: perhaps sunlight is necessary for maximum growth and full pigment development.

    Graphium choredon
    (Photo: courtesy of Di Donovan, Beecroft, New South Wales)

    The eggs are off-white and spherical, with a diameter of about 1 mm. They are laid singly. The female butterfly is quite particular, usually only laying each egg on a leaf of a foodplant. Occasionally however she makes a mistake, and we have found the eggs on

  • Avocado ( Persea americana, LAURACEAE ),

    on which the young caterpillars cannot always successfully develop.

    Graphium choredon
    egg, highly magnified
    (Photo: courtesy of Ken Walker, Brisbane, Queensland)

    The species is found in Australia in:

  • Queensland, and
  • New South Wales.

    After Gray (1853): this species was thought to be a subspecies of Graphium sarpedon, although C. & R. Felder (1864) gave it the separate name choredon. However: DNA studies by Page and Treadaway (2013) have proved Graphium choredon to be a separate species.

    Graphium choredon
    mating pair
    (Photo: courtesy of Nick Monaghan, Tewantin, Queensland)

    This species is featured at Coffs Harbour Butterfly House. Butterflies of this species may be purchased for release at weddings etc.

    Further reading :

    Michael F. Braby,
    Butterflies of Australia,
    CSIRO Publishing, Melbourne 2000, vol. 1, pp. 259-260.

    Baron Cajetan & Rudolf Felder,
    Species Lepidopterorum hucusque descriptae vel iconibus expressae in seriem systematicam digestae,
    Verhandlungen der Zoologisch-Botanischen Gesellschaft in Wien,
    Band 21 (1864), p. 305, No. 218.

    George Robert Gray,
    Lepidopterous Insects : Papilionidae,
    Catalogue of Lepidopterous Insects in the Collection of the British Museum,
    Part 1 (dated 1852, issued 1853), p. 28, No. 135 b,
    Plate 4, Figure 1.

    Frank Jordan & Helen Schwencke,
    Create More Butterflies : a guide to 48 butterflies and their host-plants
    Earthling Enterprises, Brisbane, 2005, p. 7.

    Australian Butterflies
    Australian Moths

    (updated 15 March 2013, 12 May 2015, 9 June 2020, 4 September 2021)