How the humble dung beetle engineers better ecosystems in Australia

MARCH 11, 2020

by Paul Weston and Theo Evans, The Conversation

Dung beetles play an important role helping clear up all the dung left by other animals in an environment.

In Australia there are approximately 475 native species of dung beetle.

But there's a problem. Most of them are adapted to deal with marsupial dung. When British colonisers brought livestock down under, they introduced an entirely new type of dung that the native dung beetles were ill-equipped to handle.

Not touching that dung

Cattle dung is wet and bulky. It is very unlike marsupial dung—which is typically small, dry pellets—and so the native dung beetles largely left it alone. As a result, large deposits of cattle dung accumulated in the Australian agricultural landscape.

Besides fouling the land, the dung was an excellent breeding site for bush flies and other nuisance insects, as well as internal parasites that plague the digestive tracts of livestock.

So CSIRO embarked on an ambitious plan to introduce into Australia many dung beetles that were adapted to livestock dung. Starting in 1966, it imported and released 43 species of dung beetles over 25 years.

The beetles came from places such as South Africa, France, Spain and Turkey. The chosen beetles had similar climate requirements and were adapted to wild and domestic livestock, so they could live in Australia and process livestock dung.

Continued

Dung beetle has galloping gait

Scientists have discovered that three species of dung beetle walk with a "galloping" gait not seen in any other insect.

The vast majority of insect species walk with what is known as an alternating tripod gait - steadily moving forward three legs at a time.

It is not clear why these flightless beetles have shifted so radically from the usual way of walking.

The findings are reported in the journal Current Biology.

The researchers wrote: "Like a bounding hare, the beetles propel their body forward by synchronously stepping with both middle legs and then both front legs."

They beetles appeared simply to "drag" their back legs, they added.

Dr Jochen Smolka, from the University of Lund in Sweden, who carried out the research in South Africa, was studying wingless desert dung beetles in order to find out how they navigated to their burrows.

"We noticed that [one species we were looking at] was kind of bobbing along in a peculiar manner," he told BBC News.

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