Graphium choredon

Graphium choredon (C. & R. Felder 1864)
Blue Triangle or Common Bluebottle
PAPILIONIDAE, PAPILIONOIDEA

Don Herbison-Evans
(donherbisonevans@yahoo.com)
and
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.

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 ).

(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).

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.

(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.

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.

(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.

(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.

(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.

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.

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.