THE ULTRASTRUCTURE OF ACACIA CORNIGERA L. BELTIAN BODY TISSUE

Beltian bodies of Acacia cornigera have evolved as multicellular structures which serve as food for protective ant colonies. At the ultrastructural level, Beltian body cells contain a large amount of protein and lipid that presumably contribute to the ant's nutrition. The non-soluble protein is aggregated into tubules of two size classes: one is present in both the cytoplasm and nucleoplasm, and has an individual tubule diam of 75 A, while another size class, located in the cytoplasm, has a diam of 280 A. These two classes of protein tubules aggregate into units that occupy a high percentage of a cortical cell's volume. Numerous lipid droplets are present in the cytoplasm, adding an energy source to the ant's diet. Each droplet is surrounded by a single layer of filaments, the molecular composition of which is unknown at this time. This study indicates that the evolutionary development of this tissue has produced a highly desirable food source for the inhabiting ants.