Doratifera casta (Scott, 1864)
Black Slug Moth
(one synonym : Doratiophora acasta Froggatt, 1907)
Don Herbison-Evans
Stella Crossley & Ian Baird

The eggs of this Caterpillar are laid in a mass of about 40, and covered in brown fur.

Doratifera casta

When the caterpillars hatch, they feed communally. They sit on the leaf surface, touching each other, eating initially only the surface layer from the leaf. Later they separate, having a whole leaf each.

Doratifera casta

The caterpillars have been found feeding on the foliage of various trees in MYRTACEAE, including:

  • Gum Trees ( Eucalyptus species ),
  • Bottlebrush (Callistemon species).
  • Water Gum ( Tristaniopsis laurina ),
  • Brush Box ( Lophostemon confertus ),

    as well as on

  • Wattles ( Acacia, MIMOSACEAE ).

    Doratifera casta
    (Photo: courtesy of Martin Purvis, Ingleburn, New South Wales)

    The caterpillar is black, with very pale green fleshy spikes along the back, and cream fleshy spikes along the sides of the caterpillar. Four of the spikes on the thorax protrude rosettes of cream stinging hairs if the caterpillar is disturbed. Their contrasting coloration offers a warning that these caterpillars sting. The head is brown, and normally tucked under the body. The caterpillars move like slugs because their legs are reduced.

    Caterpillar attacked by the bug Oechalia schellenbergii
    (Photo: courtesy of Jenny Holmes, Great Western, Victoria)

    The caterpillars are known sometimes to totally defoliate a tree, and are then considered to be a pest. However the caterpillars have many predators and enemies that parasitise or infect them, which normally keep the population at tolerable levels.

    Doratifera casta
    caterpillars looking for a nice place to pupate
    (Photo: courtesy of Cheryl McCouat Photography, Rylstone, New South Wales)

    The caterpillars grow to length of about 2 cms. When fully grown, the caterpillars leave the foodplant and walk as far as 20 metres looking for a suitable crevice or piece of leaf litter in which to pupate.

    Doratifera casta
    (Photo: Don Herbison-Evans, Manly, New South Wales)

    The pupa is enclosed in a spherical brown woody cocoon, about 0.7 cm in diameter. The pupal period varies from 2 to 10 months.

    Doratifera casta
    (Specimen: courtesy of the Macleay Museum, University of Sydney)

    The adults have brown wings, with a row of four black dots each outlined in orange on each forewing. The moths have a wingspan of about 4 cms. They often sit with the forewings vertical, and the hind wings held horizontally, like skipper butterflies.

    The adults may easily be confused with those of of Doratifera quadriguttata, but the adults of Doratifera casta are darker and the black spots are more distinct. This is one case where the caterpillars provide much clearer identification of the species.

    The species occurs in:

  • Queensland,
  • New South Wales, and
  • Victoria.

    Further reading :

    John L. Capinera (Ed.),
    Encyclopedia of Entomology,
    Springer Science & Business Media (2008), p. 1734.

    Ian F.B. Common,
    Moths of Australia,
    Melbourne University Press, 1990, figs. 29.1, 52.13, p. 302.

    James T. Costa,
    The Other Insect Societies,
    Harvard University Press (2006), pp. 577.

    Phillip W. Hadlington & Judith A. Johnston,
    An Introduction to Australian Insects,
    UNSW Press (1998), p. 64.

    Harriet, Helena, and Alexander W. Scott,
    Australian Lepidoptera and their Transformations,
    Australian Lepidoptera,
    Volume 1 (1864), pp. 18-19, and also Plate 6, top right.

    Australian Butterflies
    Australian Moths

    (updated 29 January 2013, 17 February 2017)