Aussie dung beetles are coming

22:43, Feb 05 2011
'Dung beetles should have come to New Zealand 150 years ago,' says farmer John Pierce.

Swarms of potty-mouthed Aussies are headed for New Zealand – but they're worth their weight in gold.

Ten species of dung beetles are to be imported from across the Tasman, with the potential to save farmers over $150 million each year and reduce the country's greenhouse gas emission.

Environmental Risk Management Authority – ERMA – earlier this week gave permission for the importation, with initial releases on properties in north Auckland and Southland.

Cows avoid soiled areas.

"The introduction of dung beetles would potentially enhance our production efficiency and sustainability by improving soil health and reducing the runoff into waterways," said John Hartnell, Federated Farmers' biosecurity spokesman.

"The beetles also reduce greenhouse gas emissions from dung and urine."

The beetles could have a significant impact on the rural sector with their natural habit of laying eggs in dung and then burying it.


As the eggs hatch the grubs feed on the dung, breaking it down and turning it into a sawdust-like material that adds to the fertility of the soil. This gets rid of the dung sitting on top of the ground, while acting as a natural fertiliser.

New Zealand lacks native pastoral dung-burying beetles and, while dung decomposes naturally, intensive farming means large amounts are dropped on to pasture.

This can lead to leaching of nutrients into waterways and reduced production as cattle avoid fouled areas in pasture.

"Dung beetles should have come to New Zealand 150 years ago with the first cows and sheep, but they didn't," said organic Rodney farmer John Pierce, chairman of the group behind the project. "They're part of a whole package."

Hartnell agreed and said: "The beetles that naturally dealt with their effluent never came with them, and now we've got a chance to rectify this imbalance.

"Agricultural exports are 66% of New Zealand's total exports. Our dependence on primary production may be unique by OECD standards, but it is this that makes us leaders in our field. We must continually look for leading-edge solutions.".

Half of New Zealand's green-house gas footprint comes from agriculture. Burying dung will likely reduce the amounts of methane, nitrous oxide and carbon dioxide produced as the manure breaks down on the surface, as well as the potential to increase the amount of permanent carbon stored in the soil by nearly 20 tonnes per hectare.

Economic benefits are likely as buried dung will become a natural fertiliser, reducing expensive fertiliser applied to pasture.

Production increases will come from the removal of dung pats from pasture, which stock won't graze close to when eating.

Less dung also means less of another scourge of country life: flies. Introduced dung beetles in Hawaii have reduced pest flies breeding in dung by 95 percent, says Hugh Gourlay, one of the Landcare Research scientists involved with the project.

Sunday News