Dietary Implications of Interactions between Ants and Symbiotic Bacteria

Studies of symbiotic bacteria have demonstrated that they provide multiple benefits to their hosts. These studies, however, have overlooked the importance of interactions with other bacteria and environmental factors that affect bacterial assemblages. To understand what shapes bacterial assemblages, I manipulated the diet of ants from the genus Cephalotes and disturbed their gut microbiome. I found that a deficit of nitrogen reduces bacterial densities. Furthermore, the data suggest that bacterial abundance may influence ant survival. I followed this experiment up by manipulating a putative protein source in the field. Our lab assigned Allomerus octoarticulatus ant colonies to treatments in which potential prey were present or absent. I collected data on foraging behaviour, colony performance, and composition of the bacterial community. The absence of prey increased ant recruitment to protein-rich baits; these ants were also less fit than ants that had insect prey but their bacterial assemblages were not affected.MAS