1. What Ants Eat and Who Eats the Food Carried to the Nest
What ants eat varies by species. Some eat small insects, some eat plants, some grow mushrooms, and others eat almost anything. Many species use flower nectar or aphid honeydew as energy sources[1]. A puzzle arises when we see workers carrying solid objects. In a magazine for pest control professionals, it is explained that solid bait carried by workers is usually for larvae, as adult ants are typically considered liquid drinkers[2]. Scientific papers also state that adults consume liquids, while larvae eat liquids or solids depending on the species. The sharing of food and secretions among colony members is called trophallaxis (nutrient exchange)[3]. Thus, the worker carrying the food and the larva eating it are different. However, this does not apply to all species, as some larvae drink only liquids.
2. How Larvae Turn Solid Food Into Liquid for Adult Ants
How do adults drink solid food? A pest control magazine explains that solid food is placed on the outside of a larva’s body. The larva releases digestive fluid onto it, turning it into liquid, which workers can then drink[2]. In this way, larvae act like a "kitchen" inside the nest. In mouth-to-mouth transfer, the direction is reversed. Workers regurgitate liquid food stored in a sac called the crop to feed larvae[2]. Through this exchange, food circulates around the nest. Note that this path does not apply to all species, as some larvae drink only liquids. Another example shows the flow in reverse. In one species, pupae just before emergence produce a nutrient-rich molting fluid similar to mammalian milk, which larvae drink. Larvae that did not drink it grew poorly and had lower survival rates[4]. This is an example of one species and cannot be read as a general rule for all ants.
Food does not enter adult mouths as solids. It becomes liquid through larval digestion or circulates as liquid via mouth-to-mouth transfer.
3. How Sugar Level and Stickiness Affect the Way Ants Carry Liquid
A research group at Okayama University compared how ants transport sugar water. With 10% sugar water, 79% of ants only drank it, and 18% grabbed it after drinking. When the sugar concentration rose to 60%, the percentage of ants only drinking dropped to 35%, while those grabbing and carrying it rose to 60%[5]. Thick sugar water is not just sweet; it is also sticky. Researchers tested liquids with increased viscosity (thickness) but no added sugar. They found that 44% of ants only drank, and 44% grabbed the liquid. This led to the conclusion that increased viscosity encourages grabbing behavior[5]. Here, "grabbing" means using large jaws to hold a drop of liquid after drinking. These are experimental results under specific conditions. We cannot say this happens with every liquid in the wild, but it suggests that "sweetness" and "stickiness" work separately.
The results showed that even without higher sugar concentration, increased thickness alone encouraged ants to grab the liquid.
4. How Ants Get Sweet Honeydew From Aphids
One sweet food for ants is aphid honeydew. Aphids suck sugar-rich sap from plant tubes and excrete the excess as honeydew. Ants protect aphids in exchange for this honeydew. This relationship is considered mutualism, where both benefit. However, honeydew is not always given to ants. A study introduced by the Japan Science and Technology Agency showed that in closed plant galls, aphid honeydew has less than 0.5% sugar and is absorbed by the plant tissue there[6]. This is a different processing method than giving it to ants. Honeydew sugar levels vary by species and conditions. Recalling the previous section, ants might change how they handle liquids based on concentration.
Aphid honeydew is another source of liquid food for adult ants.
5. How Ants Began Farming Fungi More Than 50 Million Years Ago
Besides liquids and insects, ants have "farms." The tribe Attini is thought to have switched from hunting and gathering to growing fungi for food about 55 to 60 million years ago[7]. About 25 million years ago, lineages growing fungi that make small protein-rich lumps appeared. Around 15 million years ago (with some variation in estimates), leaf-cutting ants appeared, creating large farms to support colonies of millions[7]. Leaf-cutting ants carry leaves to the nest to grow fungi for food[8]. If human agriculture started about 10,000 years ago, ant farming is thousands of times older, though these dates are estimates. Leaf-cutting ants do not eat the leaves themselves; they eat the fungi grown on them. Even the workers cutting and carrying leaves eat the farm fungi, not the leaves. This overlaps with the idea that larvae digest solids.
Why did adult ants, who do not eat solids directly, use plant leaves as food? By layering roles—adults drinking, larvae digesting solids, and fungi breaking down leaves—we see that ant feeding works as a whole colony and surrounding organisms, not just one mouth.
6. How Plants Use Fatty Seed Attachments to Get Ants to Carry Their Seeds
Finally, let’s look at ants’ food from the plant’s side. Some seeds have an elaiosome, an attachment rich in fat. Ants carry these seeds to nests to eat the elaiosome, then discard the seed inside or outside the nest[9]. In December 2025, Professor Yamao and colleagues at Kyoto University announced in the journal *Plant Species Biology* that seeds of foxtail grass and autumn foxtail grass also have elaiosomes specialized for ant seed dispersal. This is the first discovery in a plant from the grass family, confirmed by field surveys and experiments with kept ants[9]. Is this always good for the plant? A study of three spring-flowering plants in European forests found elaiosomes made up 7.6 to 29.9% of seed weight. In 90 minutes, 10 to 34% of seeds were carried. Ants often ate the elaiosome on the spot. Researchers concluded this relationship is not beneficial to the plant, but neutral or slightly negative[10]. Results differ by plant and location.
7. How to Observe Ants Drinking Sugar Water in Your Garden
On a sunny day, find an ant trail. Prepare two small dishes. Put a few drops of sugar water in each. Make one solution thin and the other thick by reducing water. Place them slightly ahead of the ants and watch closely. Use a clock to time about 10 minutes to see if they drink or do something else after drinking. Do not touch the ants, and take the dishes home when finished. Comparing thin and thick liquids lets you check the story from Section 3 with your own eyes. For reading, Kyoto University’s research news (December 26, 2025) describes the foxtail grass and ant relationship in Japanese. The Okayama University viscosity study is available on the Japan Science and Technology Agency Science Portal.