Don Herbison-Evans (
(Photo: courtesy of Tom and David Sleep, Brisbane)
Initially this caterpillar is green with a strong nearly straight horn on its tail pointing backwards.
Later it develops a series of diagonal white stripes on its sides. The caterpillar is an agricultural pest on
but is perhaps most often found in suburbia on
It has also been found on plants of other families, such as :
As it matures, it becomes voracious, being observed to eat at least 28 leaves from the small-leaved privet tree a day.
As well as the green form, there is also a brown form of the caterpillar (which usually still has areas of green on it). The coloration of both forms of the caterpillar look very striking, but when the caterpillar is on a Privet bush, the spacing of the stripes is about the same as that of the leaves, and the Caterpillar becomes very hard to see. This use of colour to hide is a form of camouflage.
The caterpillar is most easily located by observing the black fecal pellets under the bush where it is feeding. When disturbed, the caterpillar lifts the front of its body, and bends its head underneath, exposing a series of white warts on its shoulders. The caterpillar grows to a length of about 8 cms.
When the Caterpillar is fully grown, it leaves the food plant and walks up to 20 metres to pupate under the surface debris of loose soil and leaves. The pupa, like that of many Hawk Moths, has a separate compartment at one end in which the haustellum develops.
The adult moth has long narrow forewings which are a boring grey colour, with a darker grey wavy pattern. The hindwings are dark grey, each with a pale area containing a wavy black line at the tornus. The abdomen is grey with a dark dorsal line. The wingspan is can be over 10 cms.
The underside is brown a series of with dark submarginal bands. The moth typically rests with the tip of the abdomen curled under the body. The male can make a hissing sound by rubbing parts of its body together.
The eggs are spherical and off-white, and laid singly on the underside of a leaf of a foodplant.
Similar species occur over much of the tropics, including
In Australia, Psilogramma casuarinae specimens have been taken in
Further reading :
Ian F.B. Common,
Moths of Australia, Melbourne University Press, 1990, fig. 41.3, pl. 29.1, pp. 50, 411.
Paul Zborowski and Ted Edwards,
A Guide to Australian Moths, CSIRO Publishing, 2007, p. 169.
(updated 3 April 2013)