The study, which is available online in Royal Society Open Science, is one of the largest ever undertaken of parasites associated with leaf-cutter ants. It began in 2000 and involved collecting, cataloging and analyzing samples of parasitic fungi called Escovopsis from dozens of colonies of leaf-cutter ants and their relatives in Brazil, Argentina, Panama, Mexico and the Caribbean islands of Guadeloupe and Trinidad and Tobago. Researchers identified 61 new strains of the fungi, which attack the ants' food source.