Ms Casey Gove1,2, Dr Maarten van Helden1,2, Dr Thomas Prowse1

1University of Adelaide, Adelaide, Australia, 2SARDI, Waite, Australia

Biography:

Casey Gove is a Masters student at the University of Adelaide working with SARDI on the Kangaroo Island Australian Sheep Blowfly eradication project (LuSIT). Casey is also the South Australian representative for the Australian Entomological Society.

Abstract:

The Australian Sheep Blowfly, Lucilia cuprina, is the primary species responsible for initiating flystrike in Australia. Flystrike, or cutaneous myiasis, is the skin infestation of fly larvae which, if left untreated, can kill the affected animal. Management practices and loss in meat and wool production costs the industry between $209-565 million annually. Increased chemical resistance, animal welfare, and environmental concerns necessitate an alternative approach. Previous attempts to develop SIT-like approaches for L. cuprina have been unsuccessful due to funding, rearing, and male performance issues. SARDI’s LuSIT project, now in its fifth year, intends to eradicate L. cuprina on Kangaroo Island (KI) using the Sterile Insect Technique (SIT). KI has a significant sheep industry, with roughly two sheep per hectare, and its isolation makes it an ideal location for a pilot eradication. If successful, the blowfly rearing facility can be transported to the mainland to other areas densely populated with sheep.

SIT requires inundation of the wild target species with sterile insects to prevent the production of offspring. To efficiently outnumber the wild population, sterile insects should be released during a low point in their annual population cycle. In the temperate climate of KI, L. cuprina overwinters as diapausing post-feeding maggots. The population low and synchronised emergence in early spring is the best time to begin releases.

The 2023 spring emergence of L. cuprina was investigated across 10 sheep farms on KI, each equipped with weather stations. Post-feeding maggots were deposited in soil emergence traps in May, June, and July. Some May and June released maggots emerged without diapause as adult flies in July/August. Peak emergence for all maggot releases occurred in October. Ongoing data analysis is aiming at identifying the responsible environmental cues for spring emergence to inform the 2024 spring release of sterile L. cuprina on KI.