In the paddocks of northern New South Wales, a tiny underground army is waging war against a powerful greenhouse gas — and winning. Dung beetles, no bigger than a thumbnail, slash methane emissions from cattle manure by 85%, according to a new study from Southern Cross University and the University of New England. The findings, published in the journal Ecological Entomology, are the first in Australia to put a number on what these busy insects do for the climate.
Methane is a potent gas that traps heat in the atmosphere. When cattle dung piles up on pastures, it creates anaerobic conditions — essentially, suffocating, oxygen-free environments — where methane-producing microbes thrive. But dung beetles burrow through the pats, tunneling and aerating them. This changes everything.
"By tunneling and aerating the dung, these beetles effectively repurpose greenhouse gases for low-emission decomposition," said Nigel Andrew, a professor at Southern Cross University. "They disrupt the suffocating and anaerobic conditions required by methane-producing microbes and shift the pathway toward aerobic respiration. Essentially, they are providing the ideal conditions for high-impact methane to be converted into lower-impact carbon dioxide."
Researchers set up controlled chambers called mesocosms and watched dung pats over 90 days. Some pats were home to four introduced beetle species: Euoniticellus intermedius, E. africanus, E. fulvus, and Onthophagus granulatus. Others had no beetles at all. The difference was dramatic. Control pats without beetles spiked with methane on days 6 and 16. Beetle-colonized pats stayed near zero methane throughout the entire experiment.
The beetles also reduced the total greenhouse gas footprint of decomposing manure by 18%. And here's the remarkable part: the climate benefits continued long after the beetles had moved on. Most insects departed by day 23, but the physical changes they made to the dung structure kept the microbial environment hostile to methane production.
While Australia has more than 500 native dung beetle species adapted to marsupial droppings, the research focused on four introduced species. Australia's scientific agency, the CSIRO, brought in over 20 dung beetle species from Africa, Hawaii, and southern Europe between 1968 and 1992 to improve soil aeration, boost pasture growth, and reduce pest fly breeding.
Co-author Jean Holley said the study adds to what these insects already do well. "Not only do they recycle nutrients, reduce fly numbers and aerate the soil, but they may also help to mitigate greenhouse gas emissions from livestock production."
Livestock agriculture is a major source of global greenhouse gas emissions, and Australia faces pressure to shrink the environmental footprint of its grazing systems. The researchers say supporting healthy dung beetle populations could be a simple, low-cost tool for farmers looking to cut emissions — no new technology required. The beetles are already working. The question now is how to help them work even harder.