isaak@apolling (Mark Isaak) (10/14/89)
I heard this story from an entomologist in Australia. I don't guarantee
I remember all the details correctly.
Australia has lots of grasslands. Ranchers saw this, said "great
pasture!", and started raising cattle.
The cattle, of course, leave droppings. Unfortunately, the dung
beetles in Australia have been raised for generations on a diet of
kangaroo droppings and have no taste whatsoever for cow patties. Thus
the cow patties just sit there and bake in the sun. Eventually, the
cow patties break down from microbes and other reasons, but by then
they've killed the plants underneath them, leaving little round bare
spots in the fields.
But is this so bad? It may look a little unsightly, but there's
plenty of grass left. However, consider the grasshopper. Grasshoppers
not only need grass to eat, they need bare ground to lay their eggs.
The pock-marked praries are ideal for them, so you get lots of locusts
eating up not only the cattle pasture, but neighboring croplands and
gardens as well.
The Australian government is working on this problem. They've
researched bringing in a new species of dung beetle from India, but
that didn't work because the new beetle didn't have sufficient defenses
against a native parasitic wasp (if I remember correctly). The problem
is still unsolved. Who knows where this story will end.
--
Mark Isaak imagen!isaak@decwrl.dec.com or {decwrl,sun}!imagen!isaak
"To undeceive men is to offend them." - Queen Christina of Sweden