The Chemical Basis for the Attine Ant-Fungus Symbiosis. Absence of Antibiotics

Abstract

The theory that attine ants maintain pure cultures of their food fungi by application of antibiotics to their fungus gardens has been rendered untenable. Extracts prepared from the ant Atta colombica tonsipes Santschi, from its wild fungus gardens, from expended fungus gardens, and from laboratory cultures of its fungus have been assayed for antibiotic activity against a wide spectrum of microorganisms, and no significant growthinhibiting activity has been detected. The conclusion is unavoidable that the mechanism by which the attines prevent contamination of their fungus cultures by alien microorganisms does not involve the elaboration of antibiotic substances by the ants, the fungus, or any unspecified 3rd symbiont.