Too much dung to handle
The average cow drops between 10 and 12 dung pads every day. With more than 28 million cattle in Australia, this is a huge amount of dung that is produced annually. Unless the dung is buried quickly by dung beetles, pasture is smothered by dung, flies develop in that dung and nutrients flow in to waterways reducing pasture productivity. Just one large cow pad can produce up to 3000 bush flies (Musca vetustissima) in a fortnight, creating a major nuisance for people and domestic livestock.
While Australia has several hundred species of native dung beetles that make use of the fibrous pelleted dung produced by kangaroos, wallabies, wombats and other native mammals, most are unable to cope with the large quantities of dung produced by introduced livestock, particularly cattle.
CSIRO ran a program from 1969 to the mid 1990s to introduce dung beetles primarily from southern Africa and southern Europe. A total of 53 species were introduced and of these 23 have established. Some expanded their range rapidly, while others have been much slower, but overall the amount of dung burial and fly control was remarkable, the outdoor Aussie BBQ became a reality and the "Australian salute" a thing of the past.
A 2007 study 'Introduced Dung Beetles in Australia 1967-2007' confirmed that Australia's tropical and sub-tropical cattle grazing areas were served by seven to thirteen species of dung burying beetles, whereas temperate pastures had fewer than four or five species with all but one emerging in late spring and being most active during summer.
This left a two to four month gap in dung burial in early spring across southern Australia, during which time the nutrients are not incorporated into the soil, thereby missing an important opportunity to minimise dung pollution and enhance pasture growth in spring. This gap also means that there is little competition for the dung when the spring influx of migrating bush flies arrives.
Finding our exotic saviours
Our researchers restarted on two European species, Onthophagus vacca and Bubas bubalus, that had failed to establish before and are active in early spring and are suited to the climate of southern Australia. They applied for and secured permission from the Department of Agriculture and the Department of the Environment to import the beetles into Australia.
With funding from Meat and Livestock Australia and the Western Australian Department of Agriculture, the project imported the first beetles of these species from France and Spain in 2012 and additional beetles in 2013 and 2014.
The imported beetles were placed in quarantine and the eggs from these were surface-sterilised following protocols approved by the Department of Agriculture and then, following new techniques to enhance breeding, released from quarantine and transferred to artificial brood balls in the laboratory. Researchers in CSIRO's French and Canberra laboratories developed a rearing technique for each species and synchronised their development to the southern hemisphere.
Ongoing monitoring for dung beetle establishment
In the spring of 2014, both species were released at six locations across southern Australia (in WA, SA and NSW) where the climate is predicted to be optimal for establishment. The sites will be monitored over the coming years to track the establishment and success of these new dung beetle species in Australia.