GC-MS analysis of organic molecules on fungus-gardening ants

‘Higher attines’ are a taxa of ants that grow fungus as a food source in an obligate symbiosis. The symbiotic relationship between the ants and fungus is known to be chemically mediated. This research was conducted to characterize the chemical profile of the fungal gardens and ants, in an attempt to identify molecules that may be involved in this chemical mediation.One Atta texana colony, ten Trachymyrmex septentrionalis colonies, and one Mycetomoellerius turrifex colony were excavated, with 21 ants and 200-500 mg of fungus collected from each colony. The ant and fungus samples were submerged in pentane for a minimum of 3 hours. The supernatant was then run through the GC-MS. Peaks from the resulting spectra were compared to entries in the NIST library for identification. The relative abundance of each molecule was used to conduct a Bray-Curtis Dissimilarity test, and results were visualized using an NMDS plot. The NMDS plot comparing fungus samples does not show significant similarity between the colonies, suggesting that the chemical profile of the fungus is more dependent on environmental factors such as diet rather than fungal lineage or partner ant species. The chemical profiles of the ant samples are simpler in composition and do not show a high degree of similarity between individuals. Future research comparing chemical profiles between different fungal clades, or between field-collected fungus and lab cultured fungus, would help determine what factors determine the fungal chemical profile.