In response to the reports of Allen, Buren, and Silviera- 

 Guido, the Agricultural Research Service of the United States 

 Department of Agriculture funded several trips to South 

 America by federal and university scientists to search for 

 potential biological control agents for fire ants. I was 

 priviledged to participate in the first trip to Mato Grosso 

 and Mato Grosso do Sul , the homeland of S^, invicta, as a 

 member of a team of five investigators. For five weeks 

 we collected fire ants and laboriously examined them indi- 

 vidually for evidence of infection. Despite the handicap 

 of not knowing how to efficiently screen ants for disease, 

 we collected spores of two species of microsporidia. Unfor- 

 tunately, all of our attempts to infect healthy laboratory 

 colonies of S^. invicta with these spores failed. 



Since we were unable to propagate and study the exotic 

 microsporidia, a survey of pathogens of S^. geminata in Florida 

 was initiated to find a locally available host-pathogen 

 model for studies of basic pathobiology , and to develop 

 techniques for the detection and study of disease in ants. 



The pathogen selected for study in detail was Burenella 

 dimorpha Jouvenaz and Hazard, a microsporidium that is trans- 

 missible per OS and which has the advantage of producing 

 pathognomonic signs of infection in pupae of S^. geminata . 

 I have attempted to trace the history of this microsporidiosis 

 form the transmission of spores to a healthy host, through 

 the life cycle of the parasite and pathogenesis in the host, 

 to the production of spores of the succeeding generation. 



