How dung beetles saved Australia…
Everybody knows that herbivores feed on plants, carnivores on meat and omnivores gobble up everything. Fewer people would be familiar with the term fungivore (for an animal feeding only on fungi) or know what a xylophagous diet consists of (wood) or that oophages consume only eggs and embryos.
Fewer still are likely to have come across the term ‘coprophage’. And yet, coprophages are perhaps the most important of the lot, for without them we’d gradually get buried in faeces and dung. The job of the coprophages, to break down and recycle animal wastes, no doubt is an unpleasant one, but one that at the same time is of inestimable value to the web of life. Think of the brown and sticky, semi-liquid and smelly cow pads around and what would happen if they were not removed or recycled?
This was, indeed, a problem of such magnitude in Australia where the pastures are brown and dry (don’t believe an Aussie if he talks to you of lush, green meadows in Australia) that the government of Australia heavily supported a research programme designed to test, screen, and select the finest dung-removing beetle species of the world. My small role in all this was to examine the functional anatomy and ultrastructure of the dung beetle eye, but the main emphasis was to select a fast-breeding, efficient dung beetle that would not harm the native species. The goal: to give the “winners” a green card and introduce them to Australia and her acres and acres of delicious food for the chosen beetles. The few species of native Australian dung beetles were totally over-burdened with the task of removing the dung from the introduced cattle and sheep, for they had evolved to handle kangaroo poo and not the wastes of rapidly digesting grass shredding grazers. The successful species came from East and Southern Africa, because that part of the world contained many kinds of dung beetles that had evolved to deal with the dung of all those hoofed and grass-eating animals of the African steppe.
Those species that passed the test were given “immigration status” and first bred in captivity to sufficiently high population numbers, before airdrops over the Australian countryside became possible. The project was a huge success and a fine example of biological control of a system gone out of control. Cowdung pads are actually fascinating biotopes and I can clearly remember that as a boy my curiosity and admiration for the multitude of life forms in the form of maggots, flies, mites, worms, beetles, etc. in it, won out hands down against the natural repulsion one usually harbours towards all faecal matter.
But let’s also not forget that for the ancient Egyptians the dung beetle was one of their holiest creatures and even now you can’t miss the scarab jewellery when you visit a souvenir shop in Egypt. Still, what I could not resolve as a boy and don’t wish to dwell on now is, who removes the dung of the coprophages, for they must have a digestion, too, won’t they?
© Dr V.B. Meyer-Rochow and http://www.bioforthebiobuff.wordpress.com, 2016.
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