A life surrounded by and living in crap has its benefits—if you’re a dung beetle. That life is also a boon to livestock, us, and our planet. The dung beetle, who spends its days living, eating, and reproducing in poop, is a master at waste management.
Many farmers and entomologists understand the value of this lowly bug, which spends each day digging into turds, rolling them into balls, drinking out the moisture (are you still with me?), dining on the nutrients, and reproducing. Dung beetles are found on every continent except Antarctica and all of the many different beetle species belong to the Scarabaeoidea superfamily. Think of the scarab, a close relative of the dung beetle; ancient Egyptians revered them.
Today, many entomologists and farmers have high praise for dung beetles. “They are the good guys,” George Hamilton, PhD and chair of the Department of Entomology at Rutgers School of Environmental and Biological Sciences, said. “We have them here in New Jersey. On farms they aerate and consume decomposing manure. Without them, decomposition wouldn’t happen as quickly as it does now.”
Hamilton pointed out that dung beetles live on different types of manure. In Africa, for example, dung beetles help reduce piles of African elephant dung. “They provide different services such as tunneling, consuming, and aerating decomposing manure,” he said.
This service helps diminish greenhouse gas emissions and aid in carbon removal, according to a study published in Nature. Around one-third of greenhouse gas emissions come from cattle and dairy farms, and a new study in Science shows how recent rises in methane emissions are likely attributable to agriculture. Films like "Cowspiracy" have tried to bring the issue to the attention of the greater public, but the role of dung beetles is often left unmentioned.
“By simply digging through, or tunneling through, cow patties, dung beetles aerate them and reduce methane,” P.J. Liesch, extension entomologist at the University of Wisconsin in Madison’s Department of Entomology, said.
In the journal PLOS One, researchers from the University of Helsinki reported that cow patties with dung beetles released nearly 40% less methane over a summer period than cow patties with no dung beetles. While most methane released by cows comes directly from the animal and not its dung, this is still a significant percentage.
“Another interesting thing is the fact that dung beetle activity may also affect the activity of certain insects, such as reducing the numbers of pest flies that also use dung as a food source,” Liesch explained. “By physically competing with fly larvae for dung patties and also by aerating and drying out the dung, it can make it harder for the flies to successfully complete their development. It’s a case that’s difficult to quantify, but is another example of one of those ecosystem services that dung beetles can provide.”
The flies may carry disease and farmers eradicate them with pesticides, which are released into the environment. Also cattle farmers use wormers to destroy internal parasites. Those pesticides and wormers harm dung beetle populations.
“We estimate that losses in the absence of dung beetle activity would be $1.83 billion,” John E. Losey, PhD and associate professor in the Department of Entomology at Cornell University, and Mace Vaughan, conservation director at the Xerces Society for Invertebrate Conservation in Portland, OR, wrote in the journal Bio Science. They noted, “This service (that the dung beetle population provides) is saving the cattle industry an estimated $130 million per year.”
Mike Ham, co-owner of Two Crows Farm in Murphy, NC, prefers using dung beetles to pesticides to eliminate flies. “Tests have shown that adequate populations of dung beetles have reduced the number of flies at cattle and horse farms by as much as 95%,” he said. “My level of fly infestation is low thanks to the dung beetles. We don’t need pesticides out in the pastures because the dung beetles take care of the flies. I get out of the way and allow them to do what they do naturally.”
The left-over stored dung that has been buried in the ground makes more nitrogen and carbon available for the use of vegetation. Nutrient rich soil is needed for the health and welfare of soil microbes, fungi, and bacteria. Organic matter is also food for earthworms, which is another one of Ham’s favorite recyclers.
So if dung beetle populations are on the decline due to pesticides and antibiotics, what’s a farmer to do? Some purchase dung beetles online from dung beetle suppliers in Florida, Virginia, other states, and overseas. Discussions about shipping dung beetles from one part of the country to another are debated among farmers and entomologists. The concern is that non-native beetles could introduce pathogens. “You want to be careful anytime you bring in a non-native species into a habitat,” said Sean Whipple, an entomologist based in Nebraska. “Non-native dung beetles could compete with native dung beetles and reduce biodiversity.”
Mike Ham agrees. He advises farmers to breed them on their own farms by providing a nontoxic place for them to live and procreate. “Dung beetles will find their food,” he said. “It’s up to us to not stand in their way or do anything that will compromise their breeding success.”
Current major threats to dung beetles are pesticides, anti-parasite drugs, and highly managed farms where cows are raised indoors, not in cow pastures. As far as global warming’s effects on this critter, it’s too early to tell. Now, however, it’s the dung beetle who’s making inroads to combat climate change.