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(Narrator) In 1788, five cows, two bulls, 29 sheep, five rabbits
and other assorted livestock,
were landed in Australia by the First Fleet.
Of course there were the uninvited passengers too; fleas, lice and rats.
But one special passenger was missing from the livestock consignment,
the dung beetle.
Because of this omission an ecological imbalance was caused
which has lasted for nearly two centuries.
This has left Australia with several pests and without the means to control them.
To attempt to restore the balance scientists have turned to Africa.
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Many kinds of cattle evolved in Africa and along with them many types of dung beetles.
Over millions of years a balance has been established between them.
The cattle drop dung, the beetles break up the dung pads
and bury them as food for their young.
The beetle research program in South Africa is the brainchild of Dr George Bornemissza.
of the CSIRO's Division of Entomology.
(Dr Bornemissza) Here in Africa the large herds of herbivorous animals support an immensely
rich dung beetle fauna.
Through millions of years dung beetles evolved amongst these herds of game to such diversity
that south of the Sahara alone over 1800 species are already known to science.
It was therefore obvious that our attention had to be focused on this vast continent
and it's beetles.
The Division of Entomology of the CSIRO,
in cooperation with the Plant Protection Research Institute of South Africa,
established a station in Pretoria in September 1970
to serve as a base for a research project.
We started our program by surveying various game parks of southern Africa.
One of the many sanctuaries we visited was the Gorongosa National Park
near Beira in Mozambique.
One of the best ways to collect dung beetles is by trapping them in pitfall traps,
baited with pieces of intestines of smaller animals.
Special attention is being paid to the droppings of buffalo's
as the most compatible dung in shape,
size and consistency with that of domestic cattle.
In my search for bovine dung beetles in Africa
the most spectacular beetle I have found so far
was on Gorongosa Ranch in Mozambique.
On this ranch dung pats were exposed in a paddock to study the speed of dung burial,
a crucial factor in the control of flies that breed in cattle dung.
After 24 hours hardly a trace of dung was left.
Only the churned soil with a few exit holes
indicating that some of the beetles had already departed.
All the beetles that have been collected were taken into our laboratories,
sorted out and paired off for performance studies
and only the eggs of the most efficient species will get a flight to get to Australia.
(Narrator) Because of quarantine considerations, adult beetles cannot be sent to Australia.
Instead after surface sterilisation in Africa, the eggs of selected beetles are consigned
by air in specially designed containers.
[Music plays]
[Sound of jet landing]
(Airport announcement) Your attention please, this is the final call for passengers on flight
464.
(Narrator) Through the approval of the quarantine authorities strict measures are in force to
prevent the entry of any exotic parasites or diseases.
The first generation of beetles bred from the imported eggs
never leave the quarantine area
and eggs laid by these beetles have to pass through a highly effective surface sterilisation process.
Field releases of beetles are only made from later generations
mass bred from these first generation African species.
The imported eggs must be provided with suitable breeding conditions.
The dung beetle team set to work to roll handmade dung balls from local cattle dung.
As egg consignments may number up to fifteen hundred or more this can be a lengthy job.
Cavities made in the balls provide a suitable breeding chamber for the beetle eggs.
The balls are packed in sand inside their incubation tubes
and sprayed with water to ensure they retain a sufficient level of moisture.
Except for the eggs, all imported materials is sterilised as a further precaution that
nothing undesirable is introduced.
From egg hatching to the emergence of the adult beetle
may take between four and eight weeks depending on the beetle type.
Mass breeding of selected beetle species
takes place under laboratory conditions
to produce sufficient numbers for release in the field.
In the beetles so far introduced into Australia,
two types have dung dispersal behavior can be seen.
The first can be illustrated by the tunnelling beetle.
This builds its nest directly beneath the dung pad.
In order to film nesting activity, an artificial soil profile has been prepared in a sandwich
of two pieces of glass.
The beetles work in mated pairs.
With amazing vigor and determination the female excavates tunnels in the soil.
Pushing soil to the surface in front of her with a bulldozer action.
She constructs the egg chambers, or brood balls, from dung material
which has been pushed into the tunnels by the male.
In warm soil the beetles work rapidly, building a brood ball about every two hours.
After egg-laying the female seals of the entrance to the ball.
The larva hatches after about three days and starts feeding on the brood ball.
It eats the solid dung material as it has a well-developed biting and chewing mouth.
On the other hand, adaptation in the adult has produced highly specialized mouthparts,
which are only capable of sucking the liquid components of the dung.
The young beetle passes through it's pupal stage and after about thirty-five days emerges as
a young adult to dig its way to the surface and migrate to new dung pads in the vicinity
and begin the cycle again.
The second type of dung dispersal behaviour is dung ball rolling.
The ball rolling beetles disperse the dung by breaking off fragments
and forming them into balls.
There isn't always honour among ball rollers
and beetles may sometimes vie for possession of a ball.
But the rightful owner usually manages to beat of the intruder.
With prodigious energy the ball rollers go about their work,
often molding and maneuvering lumps of dung far larger than themselves.
At the chosen nesting site the female climbs onto the ball and excavates a chamber.
After a single egg has been laid, she seals off the cavity,
raising a slight mound over the egg chamber.
The ecological imbalance, which resulted from the introduction of domestic livestock into
Australia without suitable dung burying beetles
was not relieved by the naturally occurring beetle species.
These had adapted themselves to dispose of the smaller drier droppings on animals such
as kangaroos and other marsupials.
The native beetles couldn't deal effectively with the larger and wetter dung pads from
domestic livestock.
This cattle dung is the chief breeding site for pest flies.
The bush fly in temperate areas and the buffalo fly in topical areas.
[Sound of buzzing flies]
Studies carried out in temperature control insectories
have established that speed of dung burial by beetles is a critical factor in fly control.
This time-lapse sequence, filmed over some forty-three hours,
shows the activities of beetles in breaking up and burying a dung pad
alongside a control pad where beetles are absent.
If beetles are sufficiently numerous and active,
a cow pad can be buried within the first 24 hours.
At this rate of disposal, fly development in the dung will be severely restricted
and the few flies produced will be stunted, short-lived
and incapable of laying many eggs.
On the left, fly reproduction has been normal in the pad where beetles were absent.
While in this other dish, few have survived the burying activity of the beetles
and those that have are small.
Another natural enemy to help control fly populations is the Histerid beetle.
This is not a dung burying beetle but feeds directly on the fly larva in the dung pad.
No dung pad adapted Histerids were known to exist in Australia,
so this beetle species too had to be imported.
Particularly after periods of lean food supplies,
Histerids can show extraordinary enthusiasm for their work.
North on the Tropic of Capricorn, dung pads are the breeding grounds for the buffalo fly.
This is a major pest of livestock in areas such as coastal Queensland, the Northern Territory
and the Kimberley region of Western Australia.
Infestations can number thousands on one animal alone.
In the past chemical sprays were used to control the buffalo fly
but their use is now being restricted
to avoid problems of chemical residues in animal products.
A fly may bite an animal 10 to 12 times a day.
This causes extreme restlessness in cattle
and can lead to sores around the animal's eyes
and lesions of the hide due to the beast's efforts to relieve the irritation.
The dung beetle can play a key role in tropical areas
by dispersing the buffalo fly's breeding sites.
In heavily stocked cattle country dung lies around wastefully blanketing significant areas
of pasture.
The amount of dung dropped by one animal in a year
can smother and alienate up to one tenth of an acre of pasture
and there are some 25 million cattle in Australia.
Where the pads are left undisturbed
a leaching of concentrated dung nutrients
stimulates a rank fringe of grass growth, which is unpalatable to cattle
and remains ungrazed.
Where dung beetles are active this lose of pasture is avoided
and pads are rapidly broken-down.
Grass growth actually benefits from dung nutrients released and combined with the soil.
In the long term the level of soil nutrients will rise with the continued burial of dung.
Three soil samples are sown with Japanese millet seed.
In the first pot the millet plants were grown in soil alone.
In the second, dung was allowed to remain undisturbed on the surface.
While in the third, beetles were added and allowed to bury dung in the soil.
Of course this was a laboratory experiment
and in the field such dramatic variations in growth will rarely occur.
However over a period of time dung beetle activity will substantially increase the availability
of the dung nutrients for plant growth.
By studying beetle behaviour under comparable conditions of soil, climate and dung types
in Africa, and under laboratory trials in Australia,
a scientist can select the most promising beetle species
from the vast number available in Africa.
Releases of dung beetles are being made progressively throughout the chief cattle areas of northern
and southern Australia.
Field releases are made by officers of the CSIRO's Division of Entomology,
in cooperation with the state Departments of Agriculture,
farmers and others with knowledge of the local situation.
Release sites are selected where the particular beetle species is most likely to adapt best
to the local conditions and multiply and spread rapidly.
(Researcher) Well if you could give us a bit of an idea Steve as to where your property
is and what paddocks we use.
(Steve) Yes, the property is situated four miles north of Yarra Glen
in the valley of the Steels Creek.
A valley that consist of some 3,000 acres of land,
much of it creek flats and rising hill country.
(Researcher) And there are plenty of cattle in the area?
(Steve) Yes, it's a predominantly cattle area.
(Narrator) Cooperation of graziers in selecting sites is readily offered
and is vital to the success of the program.
Aside from the presence of grazing animals,
a major considerations in selecting release sites;
a suitable climate and type of soil.
The nature of the soil will affect the beetles ability to construct soil tunnels.
Areas that are subject to regular flooding should be avoided in making the initial releases
because of the likelihood of beetles drowning.
It has taken us nearly two centuries
to start putting the missing link back into the ecological chain.
While there remain many unknown factors, which may affect the success at the beetle program,
early results indicate that dung beetles will prove an outstanding example
of biological control of immense value to Australia.
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