When introduced species of dung beetles first arrived in Australia as biological control agents they certainly had their work cut out for them.
The ecological damage caused by the arrival of cows and sheep with the First Fleet in 1788 was 200 years in the making. Pastures were in ruin and the native bush fly was flourishing in sloppy, wet cow dung.
Back in the 1970s, our scientist George Bornemissza was the first person to put the biological link back in the chain. He brought in the first introduced dung beetle species as biological control agents.
The dung beetles’ legacy continues
Fast forward to June 2021 and a new shipment of Moroccan dung beetles (Gymnopleurus sturmi) has arrived on Australian shores.
A long way from home in northern Africa, we’re hoping the beetle will thrive in southern Australia as the climatic conditions are similar to those in Morocco.
There are 5000 species of dung beetles worldwide and Australia is home to 500 native species. Our native beetles evolved with kangaroos, wallabies and wombats. So, while they’ve picked up some skills in breaking down marsupial dung, the sloppy dung left behind by cows and sheep is no match for our local beetles.
A beetle for all seasons
Our entomologist, Dr Valerie Caron, is responsible for bringing in the new batch of beetles. “To date, 45 species have already been introduced, of which 23 have established. We’re in the process of introducing three new species,” Valerie said.
“Even though dung beetles have done a fabulous job in Australia, gaps in activity still exist. Currently, we don’t have beetles who work through spring in Southern Australia, and we need beetles working so we don’t have dung accumulating during these months,” she said.
Rolling on in
The new batch of Moroccan beetles are known as “Rollers”. They’ve acquired their name due to their nature of rolling and burying a ball of dung. Not only do the beetles lay one egg in each dung ball, but they also use dung as a food supply for adults and larvae.
And believe-it-or-not, this is our first roller rodeo (in recent times).
“This is the first time in recent years that we’ve brought in Rollers. This species aggregate and trample the dung making it impossible for flies to lay eggs,” Valerie said.
“Dung beetles aren’t just good at controlling flies. Burying dung makes nutrients available to plant roots, aerates the soil and reduces water runoff and nutrient loss. Other related benefits include fewer livestock parasites and a reduction in carbon emissions.”
We observe Australia’s strict biosecurity measures when bringing in any biological agent.
Before arriving in Australia, researchers study the beetles in the field before taking them to our lab in Montpellier, France, for biosecurity processing. Researchers then clean them and remove any mites. Once the beetles have the all-clear, they are set for travel to our lab in Canberra.
Only adult beetles are allowed in to quarantine. The adults are reared for eggs and all eggs are surface sterilised for 15 minutes then rinsed before exiting quarantine.
After quarantine, our partners in the Dung Beetle Ecosystem Engineers program rear the beetles in mass-rearing facilities for a few generations. After this, we can release adults into the field.
Where to from here
The beetles are very sensitive and will only establish when the conditions are well suited to them. While it could take up to five years to truly understand if our new Moroccan beetles thrive in Australia, our scientists are expecting big benefits from these little beetles.
26th June 2021 at 2:20 pm
I remember those paddocks of the 1950s. Some fields looked like they had a large pile of cow dung for every square yard. Tricky and squishy to negotiate as a child looking for mushrooms. As the years passed, I remember driving by and noticing there wasn’t anywhere near the amount of dung as there used to be. So if that was your doing, CSIRO, I am very impressed. Congratulations. On the downside, one time when I was nine, an excited farmer on the far side of the field held up this giant mushroom for us to see as we drove past. The mushroom was a good foot across. I have never seen anything that size since. Must be the lack of ye old piles of cow dung.
22nd June 2021 at 9:24 pm
I could swear at the Melbourne Museum there is a display of dung beetles and it says that very soon after colonisation it was realised that the native beetles weren’t processing the introduced species’ dung because it was sitting in the fields and rotting so they brought over some European ones pretty soon after. Is that not true? Thanks
24th June 2021 at 3:29 pm
Hi Jennie, thanks for your question.
Introduced dung beetles didn’t arrive in Australia until the 1960s. They were brought to Australia to process the dung from livestock that arrived with European settlers, so almost 200 years had gone by between the introduced livestock and introduced dung beetles. There are 23 dung beetle species now established in Australia and some of those are from Europe.
19th June 2021 at 10:23 pm
Why do you describe sheep dung as wet and sloppy? #farmmuch?
13th June 2021 at 8:20 am
i don’t think you should introduce them because it could create political problems
11th June 2021 at 10:03 pm
At a local scale, should these introduced dung beetle species consume all the available manure from domestic animals, is there a danger they could move onto the dung of our native species and thus, out-compete our local species?
12th June 2021 at 5:03 pm
Good question. I look forward to seeing a reply to this.
16th June 2021 at 9:27 am
Thanks for your comment. Our new dung beetles eat cow and sheep dung. We will test to see if they eat marsupial dung, however, we don’t expect they would use much as marsupial dung is much drier and more fibrous. The Moroccan beetles like dung that is wet and sloppy. Our new beetles also prefer open sites, like pastures, while most marsupials prefer some shade and tree cover.
20th June 2021 at 2:16 am
What if they adapt to Australian conditions, and after a nominal period,say 10 years start consuming marsupial dung, possibly even exclusively? Can we say this is not possible?
21st June 2021 at 5:00 pm
Hi Graeme, thanks for your question.
Dung beetles were first introduced in Australia more than 50 years ago. Since that time 23 species have established. Throughout this time, the introduced beetles have focused on the dung of livestock and haven’t moved to marsupial dung. Dung varies between animal species and most dung beetle species specialise.
For a dung beetle, dung quality depends on several things including the nutritional value (what the animal ate for example), texture and moisture content. The dung beetles we are introducing now like sloppy wet dung from cows and wetter sheep dung. Marsupial dung is usually very fibrous and much drier, making it unappetising to the introduced dung beetles.