title: Pathogenic nature of Syncephalastrum in Atta sexdens rubropilosa fungus gardens.
abstract: BACKGROUND
  Leaf-cutter ants are considered to be a major herbivore and agricultural pest in the Neotropics. They are often controlled by environmentally persistent insecticides. Biological control using pathogenic fungi is regarded as an alternative for the management of these insects. Here, we assess whether the filamentous fungus Syncephalastrum sp. is a pathogenic microorganism responsible for a characteristic disease in fungus gardens. We also characterise the damage caused by this fungus by evaluating physiological and behavioural responses of Atta sexdens rubropilosa subcolonies infected with Syncephalastrum sp.
  
  
  RESULTS
  Syncephalastrum sp. fulfils Koch's postulates characterising it as a pathogenic microorganism. Ant workers recognise the infection and remove contaminated fragments from the fungus garden. Syncephalastrum sp. infection causes an interruption of foraging activity, an increase in ant mortality, subcolony deterioration and an increase in the amount of waste generated, all resulting in subcolony death. Syncephalastrum sp. also inhibits the ant fungal cultivar in vitro. The pathogenic effect of Syncephalastrum sp. does not depend on host morbidity or stress (e.g. worker mortality caused by an entomopathogenic fungus).
  
  
  CONCLUSIONS
  Syncephalastrum sp. treatment resulted in progressive damage in subcolonies. The interactions among Syncephalastrum sp., fungus garden and ants offer new opportunities in integrated pest management of leaf-cutter ants. © 2016 Society of Chemical Industry.
authors.affiliation: Department of Biochemistry and Microbiology, UNESP - São Paulo State University, Rio Claro, São Paulo, Brazil.
authors.forename: Mariana O
authors.initials: MO
authors.lastname: Barcoto
authors.affiliation: Department of Ecology, UNESP - São Paulo State University, Rio Claro, São Paulo, Brazil.
authors.forename: Felipe
authors.initials: F
authors.lastname: Pedrosa
authors.affiliation: Centre for the Study of Social Insects, UNESP - São Paulo State University, Rio Claro, São Paulo, Brazil.
authors.forename: Odair C
authors.initials: OC
authors.lastname: Bueno
authors.affiliation: Department of Biochemistry and Microbiology, UNESP - São Paulo State University, Rio Claro, São Paulo, Brazil.|Centre for the Study of Social Insects, UNESP - São Paulo State University, Rio Claro, São Paulo, Brazil.
authors.forename: Andre
authors.identifier: http://orcid.org/0000-0002-4164-9362
authors.initials: A
authors.lastname: Rodrigues
mesh_terms: D000818:Animals; D001000:Ants / Q000254:growth & development / Q000382:microbiology*; D001522:Behavior, Animal; D009090:Mucorales / Q000502:physiology*; D010572:Pest Control, Biological; D010935:Plant Diseases / Q000382:microbiology
keywords: biological control; co-infection; inhibition; interaction; leaf-cutter ants; opportunistic fungi; sulfluramid