Food Bodies. Several (unrelated) species of plants produce bodies of tissue that accumulate (usually) proteinaceous materials, oils, or other substances. These bodies are harvested for food or otherwise used by animals (often insects). They are normally visible to the human eye. The most famous are Beltian bodies, protein-rich bodies located at the leaflet tips of certain species of Acacia. Here, ants harvest the bodies as part of the diet of their young, and in return aggressively defend their territory (i.e., the plant) against marauding herbivores. It’s not surprising that ant-acacias have notably unchewed leaves.

The common tropical American tree genus, Cecropia (pictured here), accumulates proteins in Müllerian bodies that occur on swollen pads (trichilia) of tissue at the base of petioles. These same cecropias are the ones mentioned above that have domiciles in their stems. Thus, the ants that live in these domiciles have ready access to a protein food source.

Don’t be concerned about the difference in the various kinds of “bodies.” The food bodies in each genus were described at different times by different persons - thus each genus of plants that has food bodies has a different name for these bodies. Big deal. While the different kinds of food bodies have evolved independently from one another, and are thus not strictly homologous, they are for the most part functionally (and in some cases structurally) very similar.

Another situation involves the production of oil-filled bodies (elaiosomes) on seeds. Such oil bodies, along with the seeds to which they are attached, are harvested by various insects (mostly ants). The ants are apparently interested primarily in the elaiosomes (and not the seeds themselves). In the act of harvesting the seeds the ants take the seeds into their nests - the inevitable result is that the seeds are effectively dispersed (and even planted!), without being damaged by the herbivorous ants.