Sphenarches anisodactylus (Walker, 1864)
Geranium Plume Moth
(one synonym : Oxyptilus diffusalis Walker, 1864)
Don Herbison-Evans
Debbie Matthews & Stella Crossley

Sphenarches anisodactylus
(Photo: Don Herbison-Evans, Manly, New South Wales)

This is a tiny green or brown Caterpillar which is covered in long white scale-like bristles which are modified setae. It may have a reddish line down its back. It usually feeds by tunneling into the flower buds of its food plants. From Gympie to Sydney it is a pest on:

  • Geranium ( Pelargonium x zonale, GERANIACEAE ),

    Sphenarches anisodactylus
    (Photo: Don Herbison-Evans, Concord, New South Wales)

    and it is also known to feed on various other plant species (especially the flower buds and flowers) including :

  • Brillantaisia ( Brillantaisia lamium, ACANTHACEAE ),
  • Gourds ( Lagenaria, CUCURBITACEAE ),
  • Birdseye ( Caperonia castaneifolia, EUPHORBIACEAE ),
  • Beans ( Phaseolus vulgaris, FABACEAE ),
  • Dixie Rosemallow ( Hibiscus mutabilis, MALVACEAE ),
  • Fireflag ( Thalia geniculata, MARANTACEAE ),
  • Sensitive Plant ( Mimosa pudica, MIMOSACEAE ),
  • Orchid species ( ORCHIDACEAE ),
  • Cucumber Tree ( Averrhoa bilimbi, OXALIDACEAE ),
  • Stinking Passionflower ( Passiflora foetida, PASSIFLORACEAE ),
  • Snapdragons ( Antirrhinum majus, PLANTAGINACEAE ),
  • Cocoa ( Theobroma cacao, STERCULIACEAE), and
  • Lantana ( Lantana camara, VERBENACEAE ).

    The Caterpillar grows to a length of about 1 cm.

    Sphenarches anisodactylus
    (Photo: Don Herbison-Evans, courtesy of the Gympie Gem Club Inc)

    The pupa is formed on the stalk of an eaten flower bud. It has no cocoon but is attached to the stalk by a cremaster. Its colour is green with brown patches, and it is spiny, being covered with white setae. When pupation is complete, the discarded Caterpillar skin is left crumpled up at the tail end. The pupal period is about a week.

    Sphenarches anisodactylus
    (Photo: courtesy of Christine Ashe, Wyee, New South Wales)

    The adult moths have a wingspan of about 1 cm. The fore and hind wings are each composed of feather-like plumes. These are buff with brown marks. The fringes on the hindmargin of forewing have black sections. The hind plumes each have a long black mark on the plume-tip. The legs are very long and carry tibial spurs. When resting, the moth sits with its abdomen curved up into the air,and its wings held at right angles to the body with the plumes folded, which makes it look remarkably like a piece of grass.

    Sphenarches anisodactylus
    (Photo: Don Herbison-Evans, courtesy of the Gympie Gem Club Inc)

    The species is known the world over, for example in :

  • Cook Islands,
  • Hong Kong,
  • Japan,
  • Nigeria,
  • Philippines,
  • Solomons,
  • Sri Lanka, and
  • U.S.A.

    In Australia, it has been found in :

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

    Sphenarches anisodactylus
    mating pair

    Further reading :

    J. Cassani, D.H. Habeck, and D.L. Matthews,
    Life history of a plume moth Sphenarches anisodactylus (Lepidoptera: Pterophoridae),
    Florida Entomolologist, Volume 73, Number 2 (1990) pp. 257-266.

    Ian F.B. Common,
    Moths of Australia, Melbourne University Press, 1990, Fig. 30.17, p. 333.

    Buck Richardson,
    Tropical Queensland Wildlife from Dusk to Dawn Science and Art,
    LeapFrogOz, Kuranda, 2015, p. 185.

    Francis Walker,
    List of the Specimens of Lepidopterous Insects in the Collection of the British Museum,
    Part 30 (1864), pp. 934-935, No. 18.

    Australian Butterflies
    Australian Moths

    (written 17 August 1996, updated 8 December 2017, 2 April 2019, 12 June 2020)