Zizina otis Fabricius, 1757
Common Grass Blue
(often known as Zizina labradus)
Don Herbison-Evans
Stella Crossley

Zizina otis
(Photo courtesy of Harold McQueen, Goodna, Queensland)

These caterpillars are green slug-like creatures, with short pale hairs, and a dark green stripe along the back, and a thin yellowish stripe along each side of the body. The head is brown or black, although it normally cannot be seen, as the caterpillar holds it tucked under the thorax.

Zizina otis
(Photo courtesy of Harold McQueen, Goodna, Queensland)

The caterpillars rest by day at the base of the foodplant, and feed nocturnally on various members of FABACEAE, such as:

  • Emu Foot ( Cullen tenax ),
  • Australian Indigo ( Indigofera australis ),
  • Lucerne ( Medicago sativa ),
  • Glycine ( Neonotonia wightii ),
  • Romano Beans ( Phaseolus coccineus ),
  • Garden Peas ( Pisum sativum ), and
  • Clover ( Trifolium species).

    Zizina otis
    oops: the girdle broke
    (Photo courtesy of Harold McQueen, Goodna, Queensland)

    The caterpillars grow to a length of 1 cm. The pupa is dirty pink, pale green, or pale yellow, with variable dark markings. The pupa is attached to a convenient surface by cremaster and girdle. The pupa has a length of about 1 cm.

    Zizina otis
    (Photo: courtesy of Edwin Vella, Yarramundi, New South Wales)

    The female adult has a black body, and the upper surfaces of the wings are dark brown, with a purplish blue sheen around the bases.

    Zizina otis
    (Specimen: courtesy of the Macleay Museum, University of Sydney)

    The male adult has a black body, and the upper surfaces of the wings are purplish blue except for a black edge to each margin.

    Zizina otis
    close-up, showing white spot on the antenna club
    (Photo: courtesy of Harold McQueen, Goodna, Queensland)

    The butterflies have an interesting white spot on the club of the antenna. They normally fly very close to the ground. The undersides are greyish blue with a fawn pattern of spots and stripes.

    Zizina otis
    egg, magnified
    (Photo: courtesy of Ken Walker, Melbourne, Victoria)

    The bluish toroidal eggs are laid singly on the leaves of a foodplant. Each egg is covered in a microscopic triangular network of white ribs. The eggs each have a diameter of about 0.5 mm. In summer in Melbourne, eggs that we collected hatched in three days from being laid.

    Zizina otis
    mating pair
    (Photo: courtesy of Tony Rodd)

    The species is found as a number of subspecies over most of Africa, Asia, and the Pacific, including:

  • Democratic Republic of the Congo,
  • Hawaii,
  • India,
  • Korea,
  • New Zealand,
  • Thailand,
  • Zambia,

    as well as in Australia in :

  • Queensland,
  • Lord Howe Island,
  • New South Wales,
  • Victoria,
  • Tasmania,
  • South Australia, and
  • Western Australia.

    The subspecies labdalon Waterhouse & Lyell, 1914, occurs on

  • Cape York.

    Zizina otis
    (Photo: courtesy of Trevor Jinks, North Burnett, Queensland)

    There are controversies whether all the occurrences in Australasia are of Zizina otis labdalon, and whether Zizina labdalon is a separate species.

    Further reading :

    Michael F. Braby,
    Butterflies of Australia,
    CSIRO Publishing, Melbourne 2000, vol. 2, pp. 837-838.

    Kelvyn L. Dunn,
    New and overlooked distribution records for the Common Grass Bluee, Zizina otis labradus (Godart) (Lepidoptera: Lycaenidae), in eastern Australia,
    Butterflies and Other Invertebrates Club,
    Metamorphosis Australia,
    Issue 72 (March 2014), pp. 18-26.

    Johan Christian Fabricius,
    Classi VI. Glossata,
    Mantisssa Insectorum,
    Volume 2 (1787), p. 73, No. 689.

    Australian Butterflies
    Australian Moths

    (updated 1 May 2010, 9 February 2018, 11 August 2020, 10 September 2021)