Australian fritillary butterfly
Common name: Australian fritillary
Scientific name: Argyreus hyperbius inconstans
Conservation status: The Australian fritillary is 'Endangered' in Queensland (Nature Conservation Act 1992).
Description: The adult male is light orange above, with rounded black spots and a double black subterminal line. Beneath the forewing it is pinkish orange, with the apex light orange, and otherwise marked as above. The hindwing is light orange with black markings edged with silver. The female is similar above to male, but its ground colour is paler orange with apical, subterminal and terminal black markings rather more pronounced than in the male, sometimes with the apex of the forewing and hindwing tinged with green.
Habitat and distribution: Most specimens have been collected from river estuaries or swampy coastal areas at or near sea level. They are restricted to open, swampy, coastal areas where the larval food plant, Viola betonicifolia, grows as a small, insignificant ground herb in association with Lomandra longifolia (long leaved matrush) and grasses, especially the grass Imperata cylindrica (bladey grass) This habitat is called Melaleuca wetlands, although the larval food plant does not occur in all sub-types of this plant community.
It has been recorded in south-eastern Queensland and north-eastern New South Wales between Gympie and Port Macquarie. Of the 23 recorded localities only four have extant populations. The historic sites at Glenugie Creek near Grafton (1895), Ballina (1898), Billinudgel (1910), Lauderdale (1911) and Indooroopilly (1916) among others were some of the first to be lost in the almost catastrophic trend which has followed, resulting in a range contraction of greater than 80 percent.
Behaviour and life history: Adults fly in moist or swampy places where the larval food plant grows, feeding at flowers and settling on low vegetation or on the ground. Adults can be expected throughout the year although there is presently no evidence of the adult presence in September.
One report states that in midsummer the eggs hatch in about five days and the pupal duration is seven to nine days. However, other observations about the life history recorded a larval duration of four instars over 23 days, and a brief pupal duration of only four days. It was found that all adults emerged in the morning and females, when about to oviposit, settle on the ground and crawl about in search of the host plant, which is intertwined among other ground plants. Females lay on the host plant or leaves of plants over which the host is growing.
Threatening processes: Habitat destruction is a known threat to the Australian fritillary. Investigation at a site near Condong found that 'the area had recently been sprayed with herbicide and the drains around the cane fields had been cleared and the host plants Viola destroyed'. Other possible threats include the invasion and predation by introduced ants (e.g. fire ants (Solenopsis invicta) and coastal brown ant (Pheidole megacephala) and uncontrolled butterfly collection at sites essential to the Australian fritillary.
Recovery actions:
- The remaining localities with extant populations need to be reserved and monitored to protect them from disturbance.
- Habitat requirements need to be determined and a scheme to re-establish populations at old sites or new areas where the habitat is suitable should commence.
- The factors for successful courtship need further investigation. Field caught females will readily oviposit if confined over the host, so captive populations may prove easy to obtain and could be distributed to butterfly houses in Australia for display and as a stock reserve to repopulate areas where they may be secured.
- Trials on introduced Viola species should be undertaken to see whether populations could be established in urban gardens where these species are grown as decorative ground covers.
Further information:
Sands, D.P.A. and New, T.R. 2002. The Action Plan for Australian Butterflies, Environment Australia, Canberra.
Last updated: 05 September 2006