Insects in overdrive: how dung beetles are helping farmers

Published: December 2018 By: Michael Sheather

Dung beetles may not be the prettiest but these creatures are helping improve pasture production, soil fertility, moisture retention and pest control.
Dung beetle with its ball of dung
The humble dung beetle at work.
For dairy farmer Jeff Dowell, the light-bulb moment came on a hot afternoon just before Christmas last year. He was tending his milkers when he glanced down at a large fresh cow pat and noticed something that stopped him in his stride.

“The pat was fresh, no more than an hour or so old, but it was crawling with dung beetles – small, black shiny beetles about the size of your thumbnail,” Jeff recalls. “These beetles have been on the property for years, so it wasn’t them I was looking at. It was a bush fly. There was only one. I could see it buzzing about the pat trying to settle, but the dung beetles were so active this single fly couldn’t find a space to land.”

At the same time, Jeff realised there were no flies buzzing in his face. He went over to the nearest cow and saw that there were no bush flies annoying her, either.

 
“Just a couple of weeks before, the flies were so thick and annoying around the cows that they couldn’t eat. Suddenly, the flies just disappeared and I realised the dung beetles had interrupted the fly breeding cycle. That started me thinking about what else they might be able to do.” 


THE PERKS OF DUNG BEETLES 

As Jeff has since discovered, dung beetles can do a lot. In fact, they may be one of the entomological world’s greatest gifts to farmers. Dung beetles eat and reproduce in dung. It’s not a pretty life but, from a farmer’s point of view, it’s an attribute that should make the dung beetle extremely attractive.

By breaking up cow pats and burying them, they break the breeding cycle of bush flies and buffalo flies as well as animal pests, potentially reducing the need for drenching. Not only can an active, healthy colony of these little beasts bury and deconstruct cow pats at an astonishing rate, they have also been shown to improve pasture production by returning phosphorus and nitrogen to the soil, potentially alleviating the need for costly fertiliser. 

Their tunnel systems help to aerate the soil and allow greater moisture penetration and retention. At the same time, they improve soil structure and reactivate vital microbial activity. On top of that, their activity prevents nutrient runoff into waterways and reduces the incidence of algal bloom.
 

“They are, say the Australian scientists who know them best, like a tiny, shiny black vitamin pill for your soil.”


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DUNG BEETLE EXPERT WEIGHS IN ON BENEFITS

With more than 54 years’ experience in this field, John Feehan is one of the country’s – and indeed one of the world’s – leading experts on dung beetles. He is an entomologist who worked on the famous CSIRO Dung Beetle Project from 1965 until the early 1990s. This project, under the direction of Hungarian-born entomologist and ecologist Dr George Bornemissza, introduced bovine dung beetles to Australia.
 
“Dung beetles are such an important part of soil ecology,” says John, who now runs his own dung beetle consultancy in Canberra. 

They perform all sorts of vital services because they break down the dung deposited by all kinds of animals and return nutrients to the soil. The problem in an Australian sense was the dung beetles that evolved here were attuned to the droppings of our native animals, not cows. In fact, there are more than 500 species of Australian dung beetles, but they only feed and reproduce in the small, dry, pellet-like droppings of animals such as kangaroos and wombats.
 

THE PASTORAL PROBLEMS WITH CATTLE



Dung beetles are a crucial part of soil ecology, offsetting the damage caused by cow pats and other above ground disturbances.
 

“When cattle were introduced to Australia with the arrival of the first fleet back in 1788, and then developed into an embryonic cattle industry during the early 1800s, nobody envisioned that as a result we would be facing a whole slew of ecological and environmental problems more than 200 years later.”


It wasn’t until George Bornemissza arrived as a refugee from Hungary in the early 1950s that anyone identified the potential problems that came with Australia’s multi-million-strong cattle herd.

“Bornemissza saw all these cow pats sitting on the top of the pasture and, from his work in Europe, he knew dung beetles should be dealing with the droppings and redistributing them back into the soil,” says John. 

“But it wasn’t happening here. Instead, the cow pats were simply drying out and remaining on the pasture, which has all sorts of negative effects.”

HOW DUNG BEETLES HELP CONTROL THE FLIES

There are 26.2 million cattle in Australia. Individually, they produce 10 to 12 cow pats a day and each pat can incubate up to 3,000 flies in two weeks. 

That means cows drop up to 795,000 tonnes of dung on top of Australia’s productive pasture every single day, helping hatch billions of flies to annoy and spread diseases across the country’s human and animal populations. 

More than that, the cow pats take years to break down, souring the grass around them, and making swathes of pasture unproductive and contributing to waterway pollution through run-off.
 
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THE GLOBALISATION OF DUNG

The answer, Dr Bornemissza concluded, was to import dung beetles from similar climates around the world to deal with the bovine dung. It was, recalls John Feehan, a delicate process that involved dozens of people across the globe.

“First we would identify a corresponding climate to the area where the beetles were to be deployed in Australia,” he says. 

“For example, if we were to put the beetles in Canberra, then we looked at parts of France and Africa where the climate matched to give the beetles the best chance of establishing themselves. Then people would go out and collect as many egg samples as they could from these foreign populations.”


Dr. G. Bornimissza with part of his beetle collection.
Dr. G. Bornimissza with part of his beetle collection, sourced from all over the world to help with ecological issues in Australia.

Dung beetles roll dung into tiny balls, known as brood balls, which they then deposit underground. Each ball of dung contains a single beetle egg. “These brood balls were collected,” John explains.

Each one was broken open by hand. Each egg was carefully lifted out and washed in distilled water, immersed in a formalin solution for three minutes and then again washed in distilled water. This was to stop any unwanted bacteria or viruses from entering Australia. The eggs were then placed in packing material sent from Australia and shipped to Canberra. The eggs arrived in batches of 3,000 and CSIRO entomologists, John included, placed each egg by hand into a carefully constructed, man-made brood ball of Australian cattle dung. 
“This painstaking process had an initial failure rate of 98-99%. But the surviving eggs were just enough to establish breeding colonies of foreign dung beetles. It was a world first."

Between 1968 and 1984, 1.73 million dung beetles from 44 species were reared and tested in breeding facilities. The CSIRO released colonies in selected areas around Australia and 23 species survived. 

“It’s a numbers game,” says John, who is one of several dung beetle suppliers in Australia. 

“Simply put, the more beetles, the faster they bury a cow pat. With the right numbers, beetles can remove an entire cow pat in 48 hours, sometimes faster, depending on the species and the season. The dung beetles we have released around Canberra can bury cow pats in 24, 48 or 72 hours depending on the species. That’s knocked out the flies that used to plague Canberra, but the real benefit to Australia is in improving soil quality. 
 
“Only about 5% of this continent has reasonable soil and reasonable rainfall. The other 95% is marginal ground right down to unproductive desert. Farmers are bringing phosphate fertilisers from Russia, China, the US, Canada and Morocco. "

The cost of that is enormous, but we have half a million tonnes of cow dung per day that is already being deposited on our farms. It’s already in the paddocks. It’s already spread around. But it’s on top of the soil, where bush flies, buffalo flies and internal parasites complete their life cycle. If we bury that dung, then we can rejuvenate the soil for little or no cost to the farmer.”

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THE GREATEST THREAT TO THE AUSTRALIAN CATTLE INDUSTRY

John says the buffalo fly is perhaps the greatest economic threat to Australia’s cattle industry. Once a largely tropical parasite, it is now creeping south into northern NSW. These flies are blood suckers and cattle can be attacked by thousands at a time.


“This affects productivity,” says John. “That loss of blood can reduce growth by as much as 40kg – and 40kg per beast across a herd can mean the difference between a farmer surviving or going under in a financial sense.”


Dung beetles take a piece of dung from the cow pat, pass it to the female, who then withdraws into the tunnel system the beetles dig underneath the cow pat.  This tunnel system can be as big as a bicycle wheel. Once in the tunnels, the female deposits her egg into the piece of dung, fashioning it into a protective brood ball, which is then sectioned off inside the tunnels to protect it from potential predators. As a result, the cow pat is broken down and taken into the soil often as deep as 30cm, right in the grass root zone. Here, the dung, which contains valuable nutrients in the form of phosphorus and nitrogen, fertilises the soil and breaks down very quickly.

HOW DO DUNG BEETLES IMPROVE SOIL?


Dung beetle on ball of dung
A dung beetle with his brood ball, ready for deposit in the tunnels that will both aerate and fertilise the above soil.

The tunnels also aid in water penetration and retention, improving pasture production rates. Studies in South Australia have shown the Bubas bison species of dung beetle, initially introduced from France, can improve pasture growth by up to 30%. Similar studies in Western Australia showed an increase of 26% in just over a nine-month period. Increased growth rates mean the pasture can support more cattle per hectare and also allow farmers to reduce fertiliser use. Soil fertility is one of the biggest potential agricultural problems of the future, says John, who has dispatched more than 5,000 colonies of dung beetles, in 19 distinct species, across Australia since 1993. 

 
“Our current sources of phosphates are rapidly running out,” he says. “There are indications that the world may well run out of them in as little as 20 years. Cow pats are rich in both phosphorus and nitrogen, without which nothing grows.”


“If the dung lies on the surface of the soil, 80% of the nitrogen evaporates into the air. However, if dung beetles bury the cow pat that situation is reversed and 80% of the nitrogen is returned to grass roots. The nitrogen is reason enough to invest in dung beetles because it has such a productive return for the pasture. 

“The cost of a beetle colony can be roughly the cost of a single tonne of fertiliser. That’s a bargain because the farmer will get 100-1,000% more benefit from dung beetles, eventually, than they ever would from phosphate fertiliser.”
 

SHOULD YOU INTRODUCE DUNG BEETLES TO YOUR FARM?

For dairy farmer Jeff Dowell, this is a major motivating factor in his decision to introduce more species of dung beetles to his 280-hectare property near Mt Gambier in South Australia. He has released four colonies of different species to promote cross-seasonal activity. In the past, he has spent up to $70,000 a year on fertilisers. This year, he will spend almost nothing. 
 
“The thing that got me really thinking about dung beetles was the fact that as a dairy farmer I haven’t been getting a lot for my milk during the past few years,” Jeff says. “No-one has in the dairy industry. We haven’t been making much money at all in the past three years."

“Because of that, we haven’t got as much money as we had in the past for all the other costs that go along with this type of farming. We haven’t got money to spend on lots of fertiliser to keep things going. So I have cut back on fertilisers and hopefully these little beetle fellas will be able to help me out in that regard."

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“Getting all that nitrogen and phosphorus back into the soil may well be the key to cutting some of those costs for me. That’s what I am hoping anyway.”  
 

Types of dung beetle diagram
The Bubas bison is a winter-active dung beetle introduced from southern Europe thats good for environment and soil health. The Geotrupes spiniger is a tunnelling dung beetle introduced from southern Europe.
 
THE BENEFITS OF DUNG BEETLES:

- Break the breeding cycle of flies and parasites.

- Clean up pastures.

- Improve pasture production by returning nutrients to the soil.

- Aerate the soil, allowing greater moisture penetration and retention, and improving soil structure.

- Prevent nutrient run-off into waterways and reduce the incidence of algal bloom.

HOW MUCH DOES A DUNG BEETLE COLONY COST?


Budgets associated with the introduction of a dung beetle colony for a farmer are low. A starter colony of 1,500 beetles can cost as little as $400, moving up to $600-$800 for rarer species. The price also fluctuates from year to year depending on seasonal availability. Once a farmer releases a colony of beetles, there are no other costs involved. Farmers may need to look at the type of drenches they use as some chemicals are not compatible with dung beetles.

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