Beetles batting farm dung excess
Science knows them as Onthophagus binodis but they’re better known as dung beetles. Scattered onto a pile of manure, 100 of them soon dig deep into the fragrant soft brown stuff.
In less than a minute the beetles disappear into the pile shovelled together by farm owners Ian and Heather Atkinson.
The couple’s organic sheep, beef, deer and cropping farm was one of two in South Wairarapa to receive the tunnelling beetles as part of a nationwide release.
Four species of beetles will eventually be introduced in the Greater Wellington region: the Geotrupes spiniger which is active all year round, the Onthophagus taurus and Onthophagus binodis, both active and from spring to autumn, and
active during Digitonthophagus summer.
Landcare Research’s Shaun Forgie, who worked with the Dung Beetle Release Strategy Group, told 30 farmers and supporters of the project ‘‘we are completing the missing link.
‘‘ When you bring in livestock into a county which doesn’t have dung fauna you already have an imbalance in the system,’’ Forgie said. One of the reasons for introducing the beetles to New Zealand farms was to deal with the amount of manure on paddocks created by livestock which contributes to the perpetuation of parasitic worms.
The beetles would help reduce the worm infection of livestock by killing the eggs and young larvae of these worms, he said.
‘‘It is estimated that cows defecate 11 times a day. That’s an awful lot of dung appearing on your paddocks each day,’’ Forgie said. ‘‘If you have a moderate loading of dung beetles that’s a lot of tunnels produced under your fresh dung pats.’’
Tunnelling beetles increased levels of plant nutrients in the subsoil, increased aeration, reduced compaction and brought subsoils to the surface.
By burying dung, these beetles help increase the amount of organic matter in soil and stimulated microbial activity and nutrient cycling. This material also feeds earthworms and other soil organisms.
Their tunnels improve water infiltration which reduces surface ponding and helps fertiliser enter the soil. This reduces the amount of contaminants entering waterways.
Dung beetles are attracted to newly excreted dung by the aroma. Below the surface, their tunnels house eggs inside dung ‘‘sausages’’ the beetles had constructed. The sausages are eaten when the larvae hatch.
Group member John Pearce, a South Kaipara farmer, said Forgie introduced tunnelling beetles to his farm 15 years ago.
‘‘Within two to three days the dung is buried,’’ Pearce said. His complement of dung beetles has multiplied so much that they have begun to migrate to other farms along Shelley Beach.
‘‘They have gone about seven kilometres from where they were released,’’ he said.
An estimated 800 beetles are the first deliberate introduction of beneficial insects on to Mr and Mrs Atkinson’s farm.
‘‘For me, it’s very consistent with the way we’ve been trying to farm for a number of years. So, it seems like an obvious tool to use,’’ Mrs Atkinson said.
‘‘One of the ways it has interested me is that it will improve our waterways and improve fertility, improve pasture growth. It will be a win-win for everybody.
‘‘This is only the start – there are 14 types to be released. The idea of organic farms being used at the start is that there are no treatments being used, so this gives them the best chance to survive and get established.
‘‘Once they are up and going, then we’d become a repository to supply other farms.’’
For more information about dung beetles see dungbeetle.org.nz and to go on a waiting list to receive beetles, contact Agrilink NZ project manager Andrew Barber at firstname.lastname@example.org.
Good bug: Some of the 800 Onthophagu binodus dung beetles that were recently released.