The plant Psydrax odorata (Rubiaceae) produces swollen stems that are used by an undescribed species of ant (Podomyrma) as its domicile. The ant cares for scale insects within the nest, some of which are specific to that ant on that plant. There are also other organisms found in the garbage heaps within the nest, including fungi, flies and nematodes. Here, we characterise some of the interactions among these ant-plant communities.