IVOMEC®
Dung Beetle Safety
Our forefathers could never have foreseen the consequences of introducing the first sheep and cattle to Australia 200 years ago. Australia is now the world's leading exporter of many products derived from the land. This achievement is even more notable given the harsh, yet fragile environment that all producers operate in. One of the unintended and unwelcome consequences of the introduction of domestic cattle was the proliferation of bush flies and the introduction, in Northern Australia, of Buffalo Fly. In the 1950's CSIRO scientists recognised that dung beetles could provide a solution and embarked on a very successful program to identify, import, multiply and distribute species better adapted to cattle dung than the native beetles. Modern animal health remedies have helped increase production to current levels.
There are now very stringent environmental requirements and all products are extensively tested to ensure they do not adversely affect the environment. IVOMEC and IVOMEC Eprinex™ are the world's leading cattle parasiticides.More studies have been conducted using IVOMEC than any other animal health product. The results confirm that use of IVOMEC does not reduce dung beetle populations or slow the degradation of dung.

Benefits of dung beetles

By rapidly burying dung pads, dung beetles reduce fly breeding sites and therefore fly numbers. We now also know that dung burial can reduce the number of gastrointestinal parasite larvae on pastures. The beetles also help to clean up pasture and replace nutrients in the soil. The tunnels made by beetles result in greater water retention and less run-off and improve root penetration and soil aeration. Impressive results have been reported since dung beetle populations have become established. Horn Fly, a close relative to Buffalo Fly is no longer a problem in Hawaii after the successful introduction of dung beetles. Results in Northern NSW are encouraging but no reduction in Buffalo Fly numbers have yet been observed. In Busseltown, Western Australia, an 80% reduction in Bush Fly numbers has been reported. Pads attacked by beetles also produced between 48-93010 fewer parasite worm larvae than intact pads.

Life cycle

Dung beetles spend their whole life either in dung or searching for it. They can eat nothing else. Adult beetles can fly surprising distances in search of dung. Beetles have been recorded on off-shore islands up to 29 kilometres from the coast. At the peak of the dung beetle season up to 2,000 beetles can descend on a single pad.

After mating the male and female beetles work together to dig tunnels and prepare balls of dung to feed the emerging larval stages. Some beetles place the brood balls in tunnels directly under the pad. Others roll the dung ball some distance away. Still others lay their eggs in the dung pad itself. Different beetles spend from several hours to several weeks in a pad. Beetles can lay up to 80 eggs during their life time at rates of up to 5-10 per week. The eggs are laid in many different pads. Larvae hatch 1-2 days after the egg is laid. The larvae remain in the brood ball and begin to eat the dung. They pupate 1-4 weeks later and emerge as immature adults after a further 3 weeks to several months. The young adults then leave in search of new pads. Adult dung beetles live for between 1 to 24 months with most living for up to 6 months. The beetles produce 1-2 generations per year. They over-winter as either adults or pupae in the soil.


It is important to have several different species present as each is active at different times of the year. Having a diverse community will enhance the beetles' ability to disperse dung.

Safety of IVOMEC

Modern animal husbandry relies on the use of animal health products to maintain production at present levels. Internal and external parasites lead to serious disease and death with avoidable impacts on animal welfare and profitability if not treated. A number of products are used to control insects and might have unintended effects on non-targeted beneficial insects such as dung beetles.

Selection of products that are effective against target parasites, safe for the animal, operator and the environment presents a considerable challenge to the development of modern products. IVOMEC and IVOMEC Eprinex have been extensively tested for safety to ensure that no adverse environmental impact will eventuate from their use. There are more than 3,000 scientific papers published on these products.

Over 130 articles concern dung beetles. This research has been carried out in laboratories and on farms in 11 countries on 5 continents including Australia, Africa, North and South America and Europe. Ivermectin, the active ingredient of IVOMEC, has now been evaluated in studies with over 160 individual species of dung beetles and nearly 40 species of flies which breed in dung. Some studies were carried out over two successive years. No detrimental effect on the population or diversity of dung insects was described.

Trials have also investigated the effect of treatment with IVOMEC products on dung degradation. Degradation is a complex process that involves a variety of factors, both biological (birds, earthworms, insects, bacteria and fungi) and physical (weather, mechanical disturbance and faecal moisture content).

In addition it was found that dung from cattle treated with IVOMEC had normal populations of:

  • BACTERIA
  • FUNGI
  • EARTHWORMS
  • ADULT DUNG BEETLES

Trials to evaluate the effect of treatment on the persistence of cattle, horse or sheep dung have been conducted under a wide range of conditions in Australia, Europe, United States and Africa. Two thirds of the 18 studies have shown no delay in degradation of dung; five did demonstrate a delay and in 1 trial degradation was accelerated. Some of the variation might be explained by differences in experimental design. Some studies were conducted under conditions not representative of the natural environment. For example, in studies where dung degradation was prolonged, experimental dung pads were used and were protected against mechanical break-down by grazing animals and birds. Such protection can make it difficult to apply these results to normal field conditions.

Independent reviews have confirmed that IVOMEC is not detrimental to dune beetle activity New South Wales Agriculture reported results from a dung beetle project run on the NSW North Coast and South Eastern Queensland from 1996 to 1999.

Findings from the project were:

  • Warmer weather was associated with more dung beetles
  • Treating cattle with synthetic pyrethroid insecticides was associated with reduced dung beetle activity
  • Treating cattle with macrocyclic lactone and organophosphate insecticides did not appear to reduce dung beetle activity

The National Registration Authority recently commissioned a thorough review of the possible effect of all the Macrocyclic lactones (ML) products, including IVOMEC, CYDECTIN and DECTOMAX, on dung beetles. The review was conducted by an eminent CSIRO scientist and included both published and unpublished data.

The NRA concluded that:
"... there is no clear evidence to demonstrate that any of the macrocyclic lactone products have a long term detrimental effect on dung beetle populations or dung disappearance rates in the field in Australian conditions".

Australian Background

There are approximately 7,000 species of Dung Beetles in the world. Australia has some 315 species of native beetles. These have adapted to using the comparatively dry fibrous faecal pellets of our native marsupials. They are largely restricted to forest and woodland habitats, and mostly in areas of higher rainfall. Adult activity is restricted to the moist periods of the year. The CSIRO initiated a program to identify, import, multiply and distribute dung beetle species that were adapted to open grassland, cattle dung and Australian climatic conditions. Beginning in 1968 a total of 52 species of dung beetles were imported from Africa, France, Greece, Spain and Turkey. Forty-two of these species were released and by 1991 twenty-two had established breeding populations. Some species occur over much of the continent, whereas others are restricted to Northern (summer rainfall) or Southern (winter rainfall) regions. Table 1 lists some of the introduced beetles and their distribution.

Table 1: Species of introduced dung beetles established in the summer and winter rainfall zones of Australia

Establishing and Maintaining Dung Beetles on Your Farm

Absence of dung beetles or a reduction in dung beetle numbers might be because:

  • Seasonal conditions at the time were too cold or too dry for large populations to be readily observed
  • The beetles haven't spread to your property
  • The beetles are present in numbers too low to easily find. It may take 2-3 years for numbers to increase, even after a successful introduction
  • The beetles were unsuited to the local environment so they left or died out

It is important to establish a number of different types of beetles, as each species is highly active for only part of the year. Matching the correct beetle to your environment is best done after talking to an expert. Contact your local Department of Agriculture or Landcare group. Because dung beetles are mobile they will not stay where they have been released. Consequently consideration should be given to introducing beetles by a group of neighbours. In the early stages of dung beetle establishment it is recommended that you monitor the population on your farm. Remember however that climate can have a huge impact on dung beetle populations. Most beetles are morn active in warm moist conditions and decrease during dry or cold periods.

Monitoring involves assessing both dung beetle activity and the diversity of species present. NSW Agriculture suggests the following program:

  • Monitor the dung beetle population once a month
  • Rate dung beetle activity as 'nil', 'low', 'medium' or 'high'. 'Nil' means no activity as seen in dung pads, and 'high' means that most pads are rapidly dispersed
  • Count the number of each species of dung beetle present in four dung pads. The dung pads need to be 18 to 48 hours old and show evidence of dung beetle activity. Put the dung pads plus 5cm of soil from under the pad, into a tub of water. Break up the pad and wait a few minutes, then collect the beetles as they float to the surface.

Conclusion

Dung beetles have had some success in reducing Bush and Buffalo Fly numbers since their introduction to Australia. They have the potential to further reduce fly populations, to reduce gastrointestinal worm larvae on the pasture, to improve soil structure and fertility and to facilitate a higher population of earthworms. The adult beetles are mobile, and spend their time either in dung pads or searching for fresh ones. Once established the beetles can help to rapidly remove dung pads. Substantial scientific effort has been undertaken to investigate the environmental safety of IVOMEC. Dung from treated animals has no effect on bacteria, fungi or earthworms. Routine use of IVOMEC or IVOMEC Eprinex does not affect dung beetle populations and does not reduce the rate of dung degradation under field conditions.

Contact CRT Kyneton or CRT Seymour
©Steve Cselka 2006 - 2011