Emperor Gum Moth
(previously known as Antheraea eucalypti)
(Photo: courtesy of Merlin Crossley, Melbourne, Victoria)
The early instars of this Caterpillar are dark brown, with two orange spots by the head and two yellow spots by the tail. In later instars these develop into tubercles, when the first three abdominal segments develop a conspicuous orange and yellow dorsal pattern.
As the caterpillar grows, it becomes bright green on top, and still black underneath, and looks quite different. Each segment develops six tubercles with spiky yellow hairs on their tips, and the tubercles themslves are various colours. Most are yellow, but some are red, and by the head, some are purple. A yellow line runs along each side of the body, and this mimics the mid-rib of a leaf.
The caterpillar feeds in daylight, and is usually upside down. Its camouflage depends on light falling on it from the right direction, as it is paler on top than underneath. If turned up the right way, it is much more conspicuous.
If disturbed, the caterpillar lifts the front of its body and curls the head underneath it. In the the last instar, the underside also becomes green, and all the tubercles have purple tips.
The caterpillar feeds on the foliage of many plants in MYRTACEAE including:
and has also been found on:
The caterpillar grows to a length up to 8 cms. It pupates in a hard cocoon attached to the trunk of its food tree. Inside the cocoon is a brown pupa. The resting period of the pupa has been found to vary between three weeks and a year.
When the moth inside the pupa is fully developed, in order to emerge from its cocoon it first scratches at one end to weaken the wall. Then using a pair of sharp hooks just behind its head, it moves round and round inside until it cuts a hole in the end of the cocoon. It then forces its way through this hole, and immediately climbs to a position where it can hang upside down to expand its wings.
The moth is brown with shades varying from yellowish to reddish. The moths have wrinkled wingtips, and a small thin dark-edged white triangle near the leading edge of each forewing, about one quarter the way along. Each wing has a single eyespot in the middle. This is a dull pink on the forewings, and a more spectacular red with a black circle on the hindwings.
The moth usually rests with the forewings covering the hind eyespots, and exposes them if disturbed. The moths also tend to bend their abdomen to one side, which presumably breaks the bilateral symmetry, making it less recognisable as an animal. The wingspan is usually in the range 8 to 13 cms.
The adult moths have degenerate mouthparts, and so cannot feed. They rely for energy solely on the food ingested by the Caterpillars, earlier in their lives.
The males and females differ most obviously in the antennae: the females having thread-like antennae, and the males feathery antennae.
The eggs are oval and off-white, darkening as hatching approaches. They are laid in an irregular clusters of around 30 at a time.
The species occurs in
as well as over most of Australia, including:
This species was moved from the genus Opodiphthera to Austrocaligula by Brechlin in 2005, and many Taxonomists disagree with this reassignment. Here, we follow Brechlin in this most recent publication on this family.
Further reading :
Einige Anmerkungen zur Gattung Neodiphthera Fletcher, 1982 stat. rev. mit Beschreibung von vier neuen Arten (Lepidoptera: Saturniidae),
Nachrichten des Entomologischen Vereins Apollo,
N.F. 26 , Parts 1/2 (2005), pp. 17–29.
Ian F.B. Common,
Moths of Australia,
Melbourne University Press, 1990, pls. 15.1, 28.9, pp. 34, 57, 403, 405,
(listed as Opodiphthera eucalypti).
Pat and Mike Coupar,
New South Wales University Press, Sydney 1992, p. 85.
Butterflies and Moths,
Collins Eyewitness Handbooks, Sydney 1992, p. 231.
Emperor's New Clothes,
Issue 72, March 2014, pp. 1,4-7,
Butterfly and Other Invertebrates Club Inc.
Issue 51, December 2008, pp. 27-29,
Butterfly and Other Invertebrates Club Inc.
Moths of Victoria - Part 1,
Silk Moths and Allies - BOMBYCOIDEA,
Entomological Society of Victoria, 2008, pp. 26-27.
Tropical Queensland Wildlife from Dusk to Dawn Science and Art,
LeapFrogOz, Kuranda, 2015, p. 193.
Harriet, Helena, and Alexander W. Scott,
Australian Lepidoptera and their Transformations,
Volume 1 (1864), pp. 1-3, and also Plate 1.
Paul Zborowski and Ted Edwards,
A Guide to Australian Moths,
CSIRO Publishing, 2007, pp. 20, 162.
(updated 16 September 2008, 17 July 2018, 15 September 2019, 4 October 2020, 21 April 2022)