About fifty million years ago, ancestors of the Attini tribe of ants quit hunting and gathering for food to become farmers.  Today they are a highly successful group with some colonies numbering more than eight million members.  These ants, more commonly known as leaf cutter ants, grow a fungus (known as the cultivar) as their sole source of food.  The ants, however, are not the only organisms that use the cultivar for nutrients.  There also exists a parasite (the fungus Escovopsis) that will eleminate an entire cultivar crop in a few days.  The ants prevent this attack through the use of antibiotics produced by bacteria that live in crescent shaped pits on their backs.  The antibiotics prevent the growth of the parasitic fungus and allow the cultivar to grow and produce food for the colony.  This gives us a stunning example of ants using antibiotics on the rainforest floor millions of years before humans learned how to do the same in laboratories. Perhaps, this natural model will help to teach us how to avoid development of antibiotic resistance.

--Bryan Perkins