Golden sun moth (Synemon plana) - endangered species listing

The Scientific Committee, established by the Threatened Species Conservation Act has made a Final Determination to list Synemon plana Walker 1854, the Golden Sun Moth as an ENDANGERED SPECIES on Part 1 of Schedule 1 of the Threatened Species Conservation Act. Any submissions received following advertisement of the Preliminary Determination have been considered by the Scientific Committee. Listing of endangered species is allowed for by Section 10 of the Act. Synemon plana Walker 1854 (Lepidoptera: family Castniidae) has also been known in the literature as Synemon hesperioides R. Felder 1874.

NOTE:  This final determination has been superseded by the 2022 final determination.

NSW Scientific Committee - final determination

The Scientific Committee has found that:

1. Synemon plana is found in naturally treeless grassland, and occasionally in secondary grassland, dominated by Danthonia carphoides in the ACT and NSW, and by other Danthonia spp. in Victoria.

2. Adult Synemon plana are active from about mid November to early January. Individuals live only a few days. Males fly rapidly in the heat of the day but females are relatively immobile. They are unable to feed or drink and so must mate and lay eggs rapidly. Eggs are laid between tillers of Danthonia or between tillers and the soil. Larvae feed on underground parts of the Danthonia. The length of the larval stage is unknown but the most likely estimate is about two years. The larvae remain underground and pupate underground after preparing tunnels to the surface, through which the pupae can escape. The pupal stage probably lasts for about 6 weeks.

3. Synemon plana is currently known from five sites in Victoria, seven small and one large site in the ACT and a single site in New South Wales.

4. Museum records show that the species was more common prior to 1950 and the original range may have been from near Bathurst, south to central Victoria and west to South Australia.

5. The number of authentic, location specific, records from NSW is very small.

6. There has been a severe decline in the area of the habitat occupied by Synemon plana. The habitat is threatened by agricultural practices, invasion by exotic weeds and from housing development.

7. Given that:

• the known populations of the species are fragmented in distribution and that there is only one authenticated extant site in NSW;
• there is evidence of a decline from a previous wider distribution;
• there is evidence of a decline in available habitat; and,
• threats to the habitat continue, the Scientific Committee is of the opinion that criteria for listing as an endangered species specified in Section 10 of the Threatened Species Conservation Act are met. Both Sections 10(a) and 10(b) are satisfied.

C. Dickman
Chairperson
Scientific Committee

Gazetted: 15/11/96