Don Herbison-Evans (
(Photo: courtesy of Cathy Young)
These caterpillars are brown loopers, initially with a dark mark about half way along each side, on the second abdominal somite.
Later instars lose these marks and may develop other marks or have no marks at all. There is a range of variation in colour at this stage. They develop a small dorsal horn at the rear.
They rest characteristically sitting on their last pairs of legs, with their other prolegs folded into the body. They lay a silken thread wherever they travel, and if harassed, will drop down on the thread until danger passes, then they laboriously climb back up it. They have been found feeding on a wide variety of plants, including the exotic plants:
as well as the Australian native plants:
The caterpillars grow to a length of about 4 cms.
Pupation occurs in a soil cell, and the adult moth emerges about two weeks later.
The adult is grey to light brown, with a wavy lines of various shades of grey and brown. Like most Ectropis species, it has a blurry dark blotch near the middle of each forewing, and dark marks on the first abdominal segment. which align with wavy dark lines on the hindwings when the moth is at rest. The undersides are pale brown with a small brown spot in the centre of each wing. Like most geometrids, it rests with wings outspread. The adults blend in well with the bark of many trees. However, the moths show little preference for resting on such material, and are frequently found on plain walls and windowsills!
The adult female is larger than the male, with a wingspan in the range from 3.0 to 4.5 cms. The antennae is threadlike on the female, and the male has small pectinations giving the antennae a thickened appearance. The wings are not so blotchy as the similar species Ectropis bispinaria, and the wavy lines often include a distinct wavy line that ends at the centre of the bottom of the fore wing.
The eggs are laid singly and are off-white, oval, and covered in microscopic dimples.
The species occurs all over Australia, including
Further reading :
Ian F.B. Common,
Moths of Australia, Melbourne University Press, 1990, fig. 36.2, pp. 67, 367.
(updated 16 September 2013)