Research is on track to identify potential sites for the release of new species of dung beetles to combat bush fly numbers in Western Australia’s South West.
The Department of Agriculture and Food (DAFWA) has been carrying out monthly field surveys to assess current dung beetle populations and identify potential sites for the anticipated release of two new species imported by CSIRO.
DAFWA senior entomologist Rob Emery said the survey work could be grubby but it was worthwhile.
“During the past 18 months, researchers have handled hundreds of pieces of dung as part of their work to assess dung beetle numbers,” Mr Emery said.
“Two dozen traps are sampled monthly at 12 sites across the South West from Badgingarra and Quairading south to Narrikup and Vasse. In addition, biannual inspections have been carried out across an area spanning Esperance to Geraldton.
“The surveys have revealed healthy populations of dung beetles, as a result of work which began almost three decades ago to establish dung beetle populations in WA.”
Mr Emery said the traps had yielded 11 different species of dung beetle, averaging six species per site.
“One notable finding is a species we thought had not survived, which is doing very well in localised areas,” he said. “There may be opportunities to relocate this species to other suitable areas.”
Dung beetles deliver a variety of benefits to soils and pastures as well as destroy breeding sites of flies. In the South West, the high quality of cattle dung in spring, when bush fly populations build up, is making it difficult for existing dung beetles to have a consistent impact on fly populations.
CSIRO in Canberra is currently examining two species of dung beetles, Onthophagus vacca and Bubas bubalus, from Europe, which may have the potential to increase the overall effect of dung beetles on bush fly numbers.
These species are more active in spring, compared with existing dung beetles species in WA which are more active in summer and winter.
Mr Emery said identifying the best sites for the release of the new species of dung beetle was essential.
“If these sites are able to support a population of the new spring-active dung beetles, the beetles could then be harvested and redistributed to other locations in WA,” he said.
The survey is scheduled for completion in February 2014. Mr Emery said even with a successful release, dung beetles could take years to establish and build up in population.
CSIRO Ecosystem Sciences honorary fellow Jane Wright said work was progressing well in Canberra with the newly-imported beetles, supported by Meat and Livestock Australia.
“Rearing methods have been developed and we are on track to have beetles ready for limited release in the spring of 2014,” she said.
Entomologist and bush fly expert John Matthiessen, who is involved in the survey work, said it was natural for bush fly numbers in the South West to increase at this time of year.
Mr Matthiessen said bush fly numbers could increase in areas further south during December as summer winds pushed flies down from the north to start local breeding.
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