Nikki Jordan Senior Corporate Affairs Consultant
With their day-flying habits and colourful hind wings, Golden Sun Moths might be mistaken for butterflies. They were once common in the grassy plains across south-eastern Australia but have suffered profound declines from increasing development.
There are now only around six known colonies of the moth in Victoria, including one in the Wimmera, where our Conservation Reserve is helping to protect its habitat.
Male Golden Sun Moths have dark brown front wings with pale grey scales, and bronzy-brown hindwings with dark brown patches. Slightly larger than the female, the male has a wingspan of 3.4cm.
The female Golden Sun Moths have bright orange hindwings with black spots near the edge, while its forewings are similar to the males but more grey than brown. Both sexes have green eyes. Females have a wingspan of 3.1cm.
The larvae (caterpillars) live underground and feed on the roots of native grasses, particularly wallaby grasses, before they turn into a moth. Once they transform, the moth has no functional mouthparts and doesn’t eat at all.
Female moths have poor flying ability due to their small hind wing, and instead tend to walk between tussocks of grass to lay eggs. The male spends its entire life flying, searching for females to mate with. It flies in a zigzag pattern about one metre above the ground generally during the hottest part of bright sunny days from November to January.
Golden Sun Months prefer to live near natural temperate grasslands and grassy box-gum woodlands where wallaby grasses are found. Grasslands dominated by wallaby grasses are typically low and open. The bare ground between the tussocks is thought to be an important microhabitat feature for the Golden Sun Moth, as it is typically these areas where females are observed displaying their bright wings to attract males.
Reproduction and lifespan
In general female sun moths emerge from the pupa with fully developed eggs, ready to mate. After mating, the female lays up to 200 eggs at the base of wallaby grass tussocks. The eggs hatch after about 21 days and the caterpillars then tunnel into the ground, where they live for one to three years. Adult moths live for only one to five days due to their inability to eat.
Threats and recovery
Key threats facing the Golden Sun Moth include loss and degradation of habitat by urban, residential, infrastructure and agricultural development. Farming practices such as fertiliser, ploughing and grazing also impact the moth’s habitat. Weeds have also been known to reduce its habitat, particularly exotic pasture species including St John's wort.
We aim to help protect the moth and its habitat with our efforts to reduce foreign plant species and stop development on our Conservation Reserve.