PNNL

Abstract

Leaf-cutter ants cultivate specialized fungus gardens with fresh plant material. The fungus garden microbial symbionts contain the molecular machinery needed to access and transform nutrients from plant biomass that would otherwise be unavailable to the ants. Here, we evaluated the lipidomic differences between the leaves feeding the gardens, gongylidia produced by the fungus to feed the ants, and spatially-resolve regions of the fungus garden at initial to advanced stages of leaf degradation. Significant variations were observed between the sample types and garden regions. Lipids containing alpha-linolenic acid (18:3) from the leaves were enriched in the top of the gardens, but not dominant in the middle or bottom regions. Furthermore, the gongylidia was dominated by lipids containing linoleic acid (18:2). This manuscript examines how the cultivar modified the plant lipids and illustrates that leaf-cutter ants respond differently to 18:3 and 18:2 lipids with aggression and attraction, respectively, in behavior experiments.