Ants exhibit a remarkable dietary flexibility, which is a major factor in their success across nearly every terrestrial environment worldwide. These insects are fundamentally omnivores, meaning their diet includes both plant and animal matter. The precise balance of these foods varies greatly depending on the species, the local environment, and the specific needs of the colony. The colony’s nutritional demands are split into two primary categories: rapid energy for the adult worker ants and structural nutrients for growth and reproduction.
Primary Energy Sources: Sugars and Liquids
Adult worker ants, which are responsible for all foraging, defense, and maintenance, primarily require carbohydrates for quick and sustained energy. They seek out and consume various forms of liquid sugars, which provide the immediate fuel necessary for their high level of activity. These sugars can be sourced directly from the environment through plant nectars, ripe fruit juices, or tree sap.
A particularly important source of liquid carbohydrates comes from a mutualistic relationship known as trophobiosis. In this interaction, ants “tend” or protect sap-sucking insects like aphids, scale insects, and mealybugs from predators and parasites. In exchange, the ants consume the sugary liquid waste excreted by these insects, called honeydew. Honeydew is rich in carbohydrates, making this predictable, renewable food source valuable enough for ants to actively manage these insect populations.
Essential Nutrients: Proteins and Solid Foods
While adult workers rely on sugars, the queen and the developing larvae require a steady supply of protein and fats for growth, tissue formation, and egg production. Acquiring protein is a consistent priority for foragers, who obtain it through active predation of arthropods and scavenging dead insects. Worker ants may also consume seeds, a behavior known as granivory, which provides protein and lipids for long-term energy storage.
Since the adult ant’s narrow digestive tract often prevents them from ingesting solid food particles, worker ants must break down these protein sources. They chew and process the solid food into a digestible slurry, which is then fed to the larvae. The larvae are the primary consumers of protein, converting it into the materials needed for colony growth.
Specialized Diets and Colony Food Sharing
Some ant species have evolved highly specialized diets that rely on complex social cooperation or unique ecological niches. The fungus-farming ants of the tribe Attini, which include the well-known leaf-cutter ants, are an excellent example. These ants do not eat the leaves they harvest. Instead, they chew the plant material and use it as a substrate to cultivate a specific species of fungus in underground gardens. The ants then feed on specialized nutrient-rich structures produced by this fungus, making the fungus their sole source of food for larvae and a major resource for adults.
Regardless of the food source, the distribution of nutrients throughout the colony is managed by a behavior called trophallaxis. This is the mouth-to-mouth transfer of liquid food, allowing an ant that has consumed liquid sugar or a protein-rich slurry to share it with nestmates, the queen, and the developing larvae. Trophallaxis ensures that the energy collected by the foragers (primarily carbohydrates) and the growth materials processed by the workers (primarily protein) are efficiently distributed to meet the nutritional demands of the entire superorganism.