Humans took our first steps in agriculture about 25,000 years ago. However, ants have been on it much, much longer. In fact, leaf-cutting ants belong to an insect lineage that has been dealing with fungus farms for more than 50 million years. Closer in time, about 3 million years ago, these insects also began to grow flowering plants, in the current Fiji archipelago.
Now, research led by Guillaume Chomicki has shown that millions of years of ant farming have not only evolved this species, but have also reconfigured plant physiology.
Agricultural ants deposit feces rich in nitrogen directly into plants, which has led to the evolution of these ultra-absorbent structures. This means that the nutrients derived from ants are actively directed to the hyperabsorption sites. This new knowledge can offer important clues in our fight for food safety and abundance, say the authors of the study published in New Phytologis.
The custom of these ants is unique since they not only grow their food, but also their home: plants provide cavities in which ants nest. This relationship is essential for both parties: ants have lost the ability to build nests that have most of them and plants, which are epiphytic (plants that grow on the surface of trees), rely on ants to obtain nutrients and defense.
To demonstrate how the nutrition of the plants grown by these ants influenced both species, the Chomicki team tracked the deposition of nutrients by the ants within these plants. Specialized ants defecate exclusively in hyperabsortive warts on the walls of the plant, something other ants in the area do not. The results indicate that hyperabsortive warts have evolved repeatedly in plants colonized by agricultural ants.
Research reveals that because these ants supply nutrients to their crops, they have the potential to modify their nutrition, something that has led to evolutionary changes in both.
This supports the idea that millions of years of ant farming have remodeled the physiology of plants, moving from nutrients derived from ants as byproducts to active and directed fertilization. Just like our precision agriculture uses computer-controlled devices, drones and sensors to direct nutrients to the places where they are most needed, these ants have developed a special type of precision agriculture. Delving into it can help us obtain better crop yields and greater health, both for plants and for humans.