EVERY sheep producer in north-west Victoria will have their eyes on a project releasing millions of sterile male blowflies on Kangaroo Island to see whether it will suppress the blowfly reproduction rate and population – and by default the incidence of flystrike.
The release of masses of sterile male insects into the wild to mate with the females and thus reduce the next generation’s population is a method of biological insect control which has been successfully used worldwide for decades for numerous pest insects.
The Australian sheep blowfly lucilia cuprina is thought to be a good target for this sterile insect technique.
Sterilisation is induced through irradiation on the reproductive cells of the insects and not through genetic modification.
The release of sterile male blowflies on Kangaroo Island (4500km2 area, 600,000 sheep) in South Australia is under way and if blowfly suppression there is successful, it could indicate that suppression on the mainland might also be possible.
AWI program manager, animal wellbeing and industry resilience, Carolina Diaz, said that while there was no guarantee the project would be successful, the rewards could be significant of it was.
“It is hypothesised if producers could work together to strategically release sterile male blowflies within defined regions at targeted times, it might reduce fly pressure and thus reduce woolgrowers’ need for other fly management tools such as mulesing or chemicals,” Ms Diaz said.
“However, it is important the sterile male blowfly density is sufficient to dominate the already present wild, non-sterile male population, so there is less competition for the sterile blowflies to mate.
“Even if initially successful, there is always the risk that wild populations could be reintroduced through uncontrollable biosecurity gaps.
“The relative isolation of Kangaroo Island means it is a good testing ground for the technology, but it must remain biosecure from the mainland’s wild blowfly population, otherwise it will be at risk of reintroductions.”
In the current (second) phase, sterile blowflies are being released on the Dudley Peninsula (650km2) on the eastern end of Kangaroo Island which will be followed, if successful, by three years of large-scale releases across the rest of the island.
This will require the rearing of a massive 40 to 50 million blowflies per week.
Rearing and harvesting equipment, diet composition and climate control will need to be developed and optimised for production at this industrial scale.
