Autumn Gum Moth
(one synonym : Azelina inordinata Walker, 1869)
NACOPHORINI, ENNOMINAE, GEOMETRIDAE, GEOMETROIDEA
Array of eggs recently hatched.
The Caterpillars start life as one of an array of 50 or so pale green eggs laid in neat rows glued on a leaf of a food plant.
The early instars of this caterpillar are pale green with dark markings and brown heads.
Later they become dark grey-green. However, all stages have a conspicuous pair of yellow knobs on the second abdominal segment. A double row of brick-red dots marks the back, one pair of dots per segment. The caterpillars have four pairs of ventral prolegs, with the front pair slightly smaller than the others. When threatened, the caterpillars adopt a posture with the head curled around toward the tail.
They feed on the foliage in young shoots of various Gum Trees ( Eucalyptus, MYRTACEAE ) including :
Initially the caterpillars feed in a group, eating only the surface flesh of the leaves. Later instars hide during the day in a communal shelter. For this, they use a curled dying leaf, still attached to the stem. The caterpillars leave this nest at night to feed. For feeding, a Caterpillar will lie along the edge of a leaf, and feed from the edge inwards.
The caterpillars grow to a length of about 3 cms. They pupate in individual cells in the soil. The pupal stage can last for eight months.
The adult moths have light brown forewings with patches of reddish brown, especially along the hind margin, and to a lesser extent around the base. The hindwings vary from yellow to orange. The forewings have slightly recurved tips, and the hind wings have scalloped edges. The underside of each forewing has a conspicuous black submarginal streak at the apex. The moths have a wingspan of about 4 cms.
The moths usually rest with the hindwings covered by the forewings, with the forewings flat like a Concord aircraft, and sometimes angled like a tent. But sometimes the hindwings are only partly covered, and the outline resembles that of a bat. The pheromones of this species have been investigated.
The species is found over most of Australia. It is a pest in forests in
Attacks seem to worse in plantation environments with reduced tree species variety. Research has been conducted on control :
These caterpillars have been found regularly every June for several years on a particular Mottlecah tree in a Melbourne suburb. The tree appears to be none the worse for these attacks.
Further reading :
Characterisation of the Australian Nacophorini and a Phylogeny for the Geometridae from Molecular and Morphological Data,
Ph.D. thesis, University of Tasmania, 2003.
Ian F.B. Common,
Moths of Australia,
Melbourne University Press, 1990, fig. 53.13, pl. 10.16, pp. 58-59, 67, 364.
Pat and Mike Coupar,
New South Wales University Press, Sydney 1992, p. 47.
Autumn gum moth (Mnesampela privata),
State Forests of New South Wales, Sydney 1995.
Moths of Victoria: Part 5 - Satin Moths and Allies - GEOMETROIDEA (A),
Entomological Society of Victoria, 2014, pp. 32-33.
in Boisduval & Guenée: Uranides et Phalénites,
Histoire naturelle des insectes; spécies général des lépidoptères,
Volume 9, Part 1 (1857), p. 41, No. 29, and also Plate 14, fig. 4.
Peter B. McQuillan, Jan A. Forrest, David Keane, & Roger Grund,
Caterpillars, moths, and their plants of Southern Australia,
Butterfly Conservation South Australia Inc., Adelaide (2019), p. 127.
(updated 10 December 2011, 11 April 2015, 13 October 2020, 24 September 2021)