The 1.3 billion large ruminants—dairy cows and beef cattle, buffalo, sheep, goats—that burp, fart, and poop around the world emit more greenhouse gases than does the transportation industry, according to the UN.
These animals are responsible for about a third of global emissions of methane, a gas that makes up half of farming's contribution and is even more potent than the much-maligned CO2. (The other big methane offenders: the natural gas/petroleum industries and landfills.)
So any animal helping to quell gas release invites investigation. In a paper published August 7 in the journal PLOS ONE, Atte Penttilä and colleagues from the University of Helsinki report on experiments designed to see whether dung beetles affect how much methane is released from cow patties, the dung heaps that dot farm pastures.
Dung beetles, by the way, dig burrows into pasture feces and feed on the droppings of cows and other ruminants. They also deposit their eggs in the excrement, and their hatchlings feed on the same stuff. (Watch a video of an African dung beetle at work.)
The answer to the methane question was yes. The scientists found that cow patties with beetles, specifically Aphodius species, rummaging around in them released nearly 40 percent less methane over a summer period than beetle-free cowpats did...
Importantly, the study also showed that the presence of the beetles in aging cowpats increased the release of another greenhouse gas, nitrous oxide. More studies will help clear up whether this cancels out their methane-related efforts.
"In terms of the net effect on global warming, I'd say the jury is still out," said study co-author Tomas Roslin. "Much of the methane emission from cattle escapes from the front and rear of the animal; less escapes from the dung pats.
“But the beetles' actions should be weighed into any calculations of net effects, so we don't miss the mark," he said.
keyboard shortcuts: V vote up article J next comment K previous comment