Australasian Science: Australia's authority on science since 1938

Early Beetle Gets the Dung

Dung beetles imported from the south of France have been released into Western Australian grazing land after a 2-year breeding program by CSIRO.

There are about 28.5 million head of cattle in Australia. Each one produces about a dozen cowpats per day, each weighing about 2.5 kg. That’s about 12 million tonnes of dung every fortnight. And every one of those cowpats can generate about 3000 flies in that time.

The appetite of native dung beetles has ensured that Australia hasn’t been buried in manure or completely blanketed in flies. The beetles use dung as a food supply for both adults and larvae.

From past introductions, 23 species of exotic dung beetles have become established in Australia. However, there is a seasonal gap in the activities of existing dung beetle species.

The newly imported species of beetles have been selected to fill the seasonal break in activity in early spring across southern and western Australia. By introducing the spring-active beetle, the long-term goal is to ensure that dung is buried in early spring so that nutrients are returned to the soil and made available to plant roots. This will lead to increased pasture productivity and reduced run-off of nutrients into waterways.

Another benefit is that the beetles will compete with bush flies for the dung, thus slowing the build-up of fly numbers over spring, and enabling established beetle species to have a greater impact on fly populations over summer.

The two new species of dung beetle were originally imported in 2012. These were placed in quarantine and set up to breed. Their eggs were then sterilised in accordance with quarantine protocols. Following that, the eggs were taken into the laboratory outside quarantine and transferred to artificial brood balls.

These beetles were the start of a laboratory colony that has now produced sufficient beetles for field release around Kojonup in Western Australia, which was chosen because it is home to many large herds of cattle – and hence cow dung.

The first species, Onthophagus vacca, has now been released while a second species, Bubas bubalus, is planned for release in 2015.