Psilogramma casuarinae (Walker, 1856)
(often mistaken for Psilogramma menephron)
SPHINGINAE ,   SPHINGIDAE ,   BOMBYCOIDEA
 
Don Herbison-Evans,
(donherbisonevans@outlook.com)
and
Stella Crossley

Psilogramma casuarinae
early instar
(Photo: courtesy of Tom and David Sleep, Brisbane, Queensland)

Initially this caterpillar is green with a strong nearly straight horn on its tail pointing backwards.

Psilogramma casuarinae
later instar
(Photo: courtesy of Joanne Edelman, Albury, New South Wales)

Later it develops a series of diagonal white stripes on its sides. The caterpillar is an agricultural pest on

  • Olive trees ( Olea europaea, OLEACEAE ),

    but is perhaps most often found in suburbia on

  • Privet ( Ligustrum vulgare, OLEACEAE ), and
  • White Jasmine ( Jasminum polyanthum, OLEACEAE ).

    It has also been found on plants of other families, such as :

  • Trumpet Creeper ( Campsis radicans, BIGNONIACEAE ),
  • Yellow Elder ( Tecoma stans, BIGNONIACEAE ),
  • Japanese Honeysuckle ( Lonicera japonica, CAPRIFOLIACEAE ),
  • Pagoda Plant ( Clerodendrum paniculatum, LAMIACEAE ),
  • Cotoneaster ( Cotoneaster species, ROSACEAE ), and
  • Snapdragon ( Antirrhinum majus, PLANTAGINIACEAE ).

    Psilogramma casuarinae
    head and thorax close-up
    (Photo: courtesy of Trevor Jinks, Upper Burnett, Queensland)

    As it matures, it becomes voracious, being observed to eat at least 28 leaves from the small-leaved privet tree a day.

    Psilogramma casuarinae
    Brown form of the caterpillar
    (Photo: courtesy of Tom and David Sleep, Brisbane, Queensland)

    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.

    Psilogramma casuarinae
    defensive posture
    (Photo: courtesy of the Macleay Museum, University of Sydney)

    When disturbed, the caterpillar lifts the front of its body, and bends its head underneath, exposing a lot of little white tubercles on its thorax.

    Psilogramma casuarinae
    (Photo: courtesy of the Macleay Museum, University of Sydney)

    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 soil. The pupa, like that of many Hawk Moths, has a separate compartment at one end in which the haustellum develops.

    Psilogramma casuarinae
    (Photo: courtesy of Ted Cadwallader, Swan Hill, Victoria)

    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.

    Psilogramma menephron
    underside
    (Photo: courtesy of Eileen Collins, Chiltern, Victoria)

    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.

    Psilogramma casuarinae
    (Photo: courtesy of Tom and David Sleep, Brisbane, Queensland)

    The eggs are spherical and off-white, and laid singly on the underside of a leaf of a foodplant.

    Psilogramma casuarinae
    (Photo: courtesy of Tom and David Sleep, Brisbane, Queensland)

    The species occurs in Australia in

  • Queensland,
  • New South Wales,
  • Australian Capital Territory, and
  • Victoria.


    Further reading :

    Ian F.B. Common,
    Moths of Australia,
    Melbourne University Press, 1990, fig. 41.3, pl. 29.1, pp. 50, 411.

    Peter Marriott,
    Moths of Victoria - Part 1,
    Silk Moths and Allies - BOMBYCOIDEA
    ,
    Entomological Society of Victoria, 2008, pp. 28-31.

    Francis Walker,
    Catalogue of Lepidoptera Heterocera. Sphingidae,
    List of the Specimens of Lepidopterous Insects in the Collection of the British Museum,
    Part 8 (1856), pp. 210-211.

    Paul Zborowski and Ted Edwards,
    A Guide to Australian Moths,
    CSIRO Publishing, 2007, p. 169.


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    (updated 3 April 2013, 24 February 2015)