The Australian Dung Beetle Project (1965–1985), conceived and led by George Bornemissza of the Commonwealth Scientific and Industrial Research Organisation (CSIRO), was an international scientific research and biological control project using introduced species with the primary goal to control the polluting effects of cattle dung.

Background and inception Upon his arrival to Australia from Hungary in 1951, Dr Bornemissza, an entomologist and ecologist, noted that Australian farmland was covered in a large number of cattle dung pads. This was in contrast to the fields of Europe where the dung was removed and recycled back into the soil by various species of dung beetle (coprids). Native Australian species of beetle had co-evolved alongside marsupials such as the kangaroo and wombat, which produce small, hard, dry and fibrous pellets of dung. Cattle were relatively recently introduced to Australia by European settlers with the First Fleet in 1788 carrying a small herd of two bulls and seven cows. In the early 1800's cattle production greatly increased.

Cattle produce large, soft, moist dung pads. Native beetles, with a few exceptions, are not adapted to utilise this type of dung as a food source or breeding ground and so without such fauna, the dung pads remain on the pasture and take months or even years to decompose. Cattle will not feed from the area of rank pasture surrounding the dung pad, and with the large quantity of dung produced (up to 12 pads per animal per day), this reduces the area of land available for cattle grazing by as much as per year. Cattle dung is also a primary breeding ground for several pestilent species of fly and parasitic worm. Bornemissza suggested in 1960 that the introduction to Australia of foreign dung beetle species, which had co-evolved alongside bovines and large herbivores, would be beneficial in removing the dung, thus improving cattle grazing and nutrient recycling and reducing the number of flies and worms.

Aims of the project

The overall aim of the Australian Dung Beetle Project was to establish a "minifauna", that is, a subsection of the natural dung beetle fauna, of introduced dung beetles on the Australian mainland and in Tasmania. Once introduced, dung beetles in Australia were studied in order to determine their effects on:

Soil quality Experiments were carried out in South AfricaHughes, R. D. (1975), Assessment of the burial of cattle dung by Australian dung beetles, Journal of the Australian Entomological Society 14: 129-134 to assess the rate at which dung beetles returned dung to the soil to aid nutrient recycling. It was found that dung beetles returned over 90% of the faecal nitrogen excreted by each steer during the summer grazing season. Further experiments showed that the uptake of the essential minerals nitrogen, phosphorus and sulphur in plants was over 80% greater in soils where dung beetles were active compared to those where they were not. In addition, tunnelling dung beetles assist root penetration and improve water infiltration to the soil, thereby reducing runoff which can lead to the pollution of waterwaysEdwards, P. B. and Pavri, C. in Bailey, P. (2007), Pests of field crops and pastures, pub. CSIRO Publishing, Australia,

Fly control Introducing dung beetles as a means to control fly populations was first utilised in Hawaii as a biological control against the horn fly (Haematobia irritans irritans).Fullaway, D. T. (1921), Horn fly control, Hawaiian Forestry and Agriculture, 18:219-221Bornemissza, G. F. (1970), Insectary studies on the control of dung breeding flies by the activity of the dung beetle Onthophagus gazella F. (Coleoptera: Scarabaeinae), Journal of the Australian Entomological Society 9: 31-41) It was found that 96% fewer flies emerged from dung pads in open pastures with a dung beetle fauna in Hawaii compared to controls. It was surmised that the introduction of dung beetles to Australia would also have a reducing effect on the number of bush flies (Musca vetustissima) and the blood-sucking buffalo fly (Haematobia irritans exigua).Doube, B. M. (1987), Dung "Down Under", South African Journal of Science 83, p87 In addition to dung beetles, predacious beetles of the Histerid family, which are less sensitive to changes in soil moisture, were introduced to Australia as another means of controlling fly populations during periods of relative inactivity by dung beetles.Bornemissza, G. F. (1968), Studies on the histerid beetle Pachylister chinensis in Fiji, and its possible value in the control of buffalo-fly in Australia, Australian Journal of Zoology 16:673-688 However, these beetles were found to make little difference to the abundance of flies, so their introduction was discontinued in 1971.

Worm control In experiments in Pretoria, dung beetles were shown to be effective at controlling infective worm populations breeding in dung. The activity of a complex of at least 20 species of coprid in cattle and sheep dung produced an average reduction of 85% of worms.

Care had to be taken to introduce only those species that would be most compatible with the Australian climates and soil types, that were not under great threat of predation or of themselves becoming pests, and that effectively dispersed dung pads within an ideal time frame of 48 hours so as to minimise successful fly and worm breeding by disrupting their reproductive cycles.

Quarantine

It was estimated that as many as 160 species of dung beetle would need to be imported into Australia in order to establish a minifauna of beetles that would be suitably adapted for the different Australian climates and soil types. However, it was also important that no other potential pests "piggy-backed" their way to Australia with the beetles. Therefore, strict quarantine measures were established to ensure no pestilent species made their way to Australia.

The first beetles to be imported to Australia came from Hawaii. Here, dung beetles, particularly the species Onthophagus gazella, had already been successfully introduced from Africa in order to help biologically control the numbers of horn fly. It was thought that these beetles would be a safe source since the only parasite present in Hawaii that does not already exist in Australia is the giant liver fluke, Fasciola gigantean, the eggs of which do not survive ingestion by beetles. Samples of O. gazella were shipped to the CSIRO research base in Canberra, where they were kept under quarantine and observed before potential release. Unfortunately, direct importation from Hawaii was found to be unviable since it was discovered that the beetles were infested with potentially harmful pyemotid mites. For this reason, these particular beetles were never released onto Australian pastures.

However, the mite-infested beetles were not destroyed and were instead used to breed new generations of beetles under sterile conditions. Dung beetle eggs were dipped in 3% formalin for 3 minutes to sterilise them, then packed into hand-rolled dung balls for incubation. These eggs successfully developed into adult beetles and were among those in the first batches released into the wild on 30 January 1968 in Lansdown, near Townsville, Queensland. This quarantine method was subsequently adopted at the CSIRO research base in Pretoria, South Africa, with the added step of the eggs being transported by air in sealed containers of sterile peat moss.

First introductions

In the early years of the project, the dung beetle species O. gazella, which was able to remove dung pads in as little as 24 hours, showed the most promise in becoming established in Australia. After the first stocks were released onto pastureland in Northern Queensland in 1968, beetle recapture figures showed that the species had spread at the rate of 50–80 km per season, including the colonisation of two islands, Magnetic Island and Palm Island, 10 km and 30 km offshore respectively. By April 1970, O. gazella was firmly established over an area of 400 km2.

This performance however, was not uniformly excellent in all areas of Australia at all times of the season or year and so showed that Australia would need a number of other dung beetle species to fill the gaps in O. gazella'''s activity.

Australian Dung Beetle Project Research Unit in Pretoria

In order to find a suitable minifauna of beetles for Australia, Bornemissza set up the Australian Dung Beetle Research Unit in Pretoria, South Africa to find species that would complement the work of O. gazella. South Africa was chosen as a location to study dung beetles for several reasons. Firstly, there are a large number of different species from which to choose from (some 800 species south of the Zambezi and Kunene rivers alone), and these species have co-evolved alongside large bovids (e.g. African buffalo) for many thousands of years. There are also homologies between the sub-tropical climates of areas of the two countries. The political climate in other parts of Africa and the more advanced nature of scientific research in South Africa also made it an ideal location. The Plant Protection Research Institute in South Africa funded much of the work at this research base. Further field stations were also maintained in Cape Town during 1978-1980 and in Hluhluwe Game Reserve during 1981–1986.

The aim was to find beetles that would match, as closely as possible, 8 selection criteria:

1. Genuine dung-breeders Dung beetles for introduction to Australia needed to breed solely in dung and with no other food sources so as to avoid the species' becoming pests in other habitats and to eliminate the possibility that they would avoid cattle dung altogether.

2. Predominantly bovine dung-breeders Dung beetles tend to have a preference for a particular type of dung. To avoid the introduced dung beetles out-competing native Australian species of coprid that have a preference for other types of dung, the introduced species needed to prefer cattle dung over other types.

3. Dung burial efficiency The criterion was set that dung beetles selected for importation to Australia should be able to bury at least 25 ml of dung per pair per day, on a pro-rata basis depending on beetle size and rate of activity.

4. Ease of handling Beetles were chosen for export, which were able to breed easily in insectaries and could withstand the strict quarantine procedures imposed by Australian customs.

5. Fast breeder Preference was given to dung beetle species that were able to reproduce quickly in order to maintain large stocks of beetles for release onto pastureland.

6. Compatibility In order to minimise interspecific competition, dung beetles selected for export to Australia needed to be compatible with each other. Beetles that had co-evolved and co-existed (usually found on the same dung pads) were preferred.

7. Distribution range Beetles adapted to a wide geographical range were preferred as this gave an indication as to how well they would establish across the range of climates found in the large Australian continent.

8. Taxonomy Although not always possible, researchers preferred to select beetles that could be easily identified in terms of their taxonomy so as to be able to correctly identify them in mark, release and recapture follow-up experiments.

While most of this research was carried out in South Africa, it was recognised that further study in other areas of the world would be useful in selecting dung beetle species for introduction to Australian climates not matched by those in South Africa. To this end, a further research unit was set up in Montpellier, France, as a base from which to study European species that may be more suited for introduction to cooler, southern areas of Australia.

Beetle collection surveys