Schematic overview of the three components of our study: the cross-phylogeny bioassay experiments (left panel), the within-Acromyrmex bioassay experiments (middle panel), and the sub-colony evaluation of the role of in vitro antagonism on stability of novel in vivo sub-colony ant-fungus-bacterium combinations.
For the cross-phylogeny bioassay experiments, the number of ant colonies for which cultivars and Pseudonocardia strains were obtained is indicated next to a schematic tree showing four of the five distinct attine agricultural systems: Paleoattine agriculture (pink), Neoattine lower agriculture (brown), Neoattine higher agriculture (green and purple), and leaf-cutter agriculture (purple) (see [30] for details). For the within-Acromyrmex bioassay experiments, the number of colonies from each of the five Acromyrmex species is likewise indicated. The right panel (sub-colony experiment) indicates the approach of the experiment: novel ant-fungus-bacterium combinations were performed in which there was directional antagonism from one, both, or none of the mutualists. The role of antagonism on stability was assessed by evaluating fungus garden mass and abundance of Pseudonocardia on ant cuticles (see main text for details).
More »