Species of beetles use dung in different ways. Most species excavate tunnels in the soil under or next to the dung pad. They carry the dung down into the tunnels and fashion it into balls in which the females lay their eggs.
Other beetles carve a mass out of the dung and move it some distance from the pad before burying it. Some species simply butt the mass across the ground. Others knead pieces of dung into smoothly-rounded balls and roll them for many metres before burying them.
Egg laying subsequently takes place in the soil chamber where the ball has been buried.
At some times of the year some species of beetles shred the dung instead of burying it. This process is still effective in controlling flies.
Ten introduced beetle species are established in the south-west.
Eight are widespread:
- Onthophagus taurus, Onitis aygulus, Euoniticellus pallipes and Bubas bison can be found across much of the south-west.
- Onthophagus binodis and Euoniticellus fulvus are throughout the lower south-west coastal district.
- Onitis alexis and Euoniticellus intermedius are in the region extending north of Perth and beyond Geraldton.
Application by CSIRO to import two new species of dung beetle was approved in October 2011 along with a collaborative agreement between DPIRD and CSIRO, which will ensure that the new dung beetles will be made available to WA as soon as possible.
While the new species (Bubas bubalus and Onthophagus vacca) are not ideally adapted to all WA conditions, they are expected to be active earlier in the season than the present dung beetle species. Experts remain hopeful that the new introductions will have some further impact on bush fly populations.>
Copris hispanus currently has a very limited distribution, having not dispersed very far from the original release site. This is a very large winter active beetle that buries good quantities of dung.
Redistribution of this species is underway with the expectation of a number of new populations established within a few years.
Survey of performance
DPIRD began a two-year survey of dung beetles in the south-west to examine the populations and their impact on bush fly numbers, ensuring we have the best sites for the release of these new varieties of dung beetle.
Trapping occurred at 12 locations including previous trial sites, field surveys have also been undertaken to complement these trapping sites. This work has studied the distribution of a number of species including Bubas bison and Onthophagus taurus extending significantly on previous knowledge.