Some species of ants have developed a fascinating relationship with aphids that resembles agriculture. Instead of hunting or preying on them, these ants actively protect and care for aphids to harvest a sweet liquid called honeydew. This behavior, often described as “farming,” benefits both insects—the ants receive a reliable food source, and the aphids gain protection from predators and parasites.
The relationship begins when ants locate a colony of aphids feeding on plant sap. Rather than attacking, the ants gently stroke the aphids with their antennae, prompting them to excrete droplets of honeydew. The ants then collect and consume this sugary substance. Over time, they become devoted caretakers, ensuring the aphids remain safe and productive.
These ants are highly protective of their “livestock.” They chase away predators such as ladybugs and lacewings and even move aphids to new plants when food becomes scarce. This behavior ensures a continuous supply of honeydew while allowing the aphid colony to expand under the ants’ supervision.
Some ant colonies take their care further by sheltering aphids inside their nests during harsh weather or nighttime. Once conditions improve, the ants carry the aphids back to fresh plant growth, resuming their farming routine.
The farming relationship between ants and aphids is a powerful example of mutualism in nature. Each benefits from the other’s presence—one gaining nourishment, the other gaining protection.
Ants that Farm Aphids
Black Garden Ant (Lasius niger)
This common European ant is one of the most frequently observed aphid farmers. They aggressively protect colonies of aphids on rose bushes, broad beans, and many other garden plants. The ants will move the aphids to new, succulent growth and defend them fiercely from ladybugs and other predators in exchange for honeydew.
Yellow Meadow Ant (Lasius flavus)
These ants farm root-feeding aphids underground. They build large, grassy mounds to house both their colony and their “herds” of aphids, which feed on the roots of plants. This relationship is so secluded that the ants can obtain all the honeydew they need without ever leaving the nest.
Red Wood Ant (Formica rufa)
Known for building massive, conspicuous mounds in forests, these ants maintain extensive “aphid pastures” in the trees surrounding their nests. They create well-trodden pathways up tree trunks to tend to aphids feeding on sap, and their territorial nature makes them excellent protectors of their herds.
European Fire Ant (Myrmica rubra)
An aggressive, stinging species, the European Fire Ant farms aphids on both low-lying plants and in root systems. Their potent sting allows them to effectively deter any predator that threatens their honeydew source. They are known to move their aphid herds between different food plants.
Carpenter Ants (Camponotus spp.)
Many species of large Carpenter Ants engage in aphid farming. They will tend aphids on plants and trees, often using the honeydew as a significant part of their carbohydrate intake. They are particularly known for farming aphids on peonies and other ornamental shrubs.
Argentine Ant (Linepithema humile)
This highly invasive ant forms enormous “supercolonies.” Their success is partly due to their efficient farming of aphids, scales, and other honeydew-producing insects. By providing protection, they ensure a massive, reliable food source that fuels their rapid expansion and displacement of native ants.
Cornfield Ant (Lasius alienus)
Common in North America, this ant farms aphids on the roots of crops like corn, potentially protecting pest populations that can damage agriculture. They are known to move their aphids to new host plants and will vigorously defend them from intruders.
Texas Leafcutter Ant (Atta texana)
While famous for farming fungus, these ants also engage in a form of aphid farming. They tend mealybugs (close relatives of aphids) within their vast underground fungus gardens. The mealybugs feed on the fungus garden’s roots, and the ants harvest the honeydew they excrete.
Thatching Ant (Formica obscuripes)
Common in western North America, these ants build large thatched nests and are aggressive aphid ranchers. They manage large populations of aphids on nearby trees and shrubs, and their foraging trails can be extensive as they travel between their nest and their aphid herds.
Silky Ant (Formica fusca)
A widespread and adaptable species, the Silky Ant is a confirmed aphid farmer, though it is less aggressive than some of its relatives. They tend aphids on a variety of plants and will transport them to optimal feeding sites, demonstrating the classic herding behavior associated with this symbiotic relationship.
Red Imported Fire Ant (Solenopsis invicta)
This notorious invasive species is a highly aggressive and effective aphid farmer. They tend a wide variety of honeydew-producing insects, including aphids, scales, and mealybugs, on both agricultural crops and wild plants. Their protection of these pests can lead to significant crop damage, as it allows aphid populations to flourish unchecked by natural predators.
Asian Weaver Ant (Oecophylla smaragdina)
These arboreal ants are master architects, building nests by weaving leaves together with silk produced by their larvae. They maintain large “herds” of sap-sucking insects like scale insects and mealybugs within the canopy of trees. They are so territorial and aggressive that they can provide complete protection for their herds from virtually all predators.
Honeypot Ant (Myrmecocystus spp.)
While famous for their living food storage repletes, honeypot ants also actively farm aphids and other hemipterans. They gather honeydew from these insects and use it to feed their specialized workers that become engorged and hang from the nest ceiling, acting as living pantries for the entire colony.
Acrobat Ant (Crematogaster spp.)
Easily identified by their heart-shaped abdomens that they raise in defense, Acrobat Ants are common arboreal farmers. They frequently tend aphids and scales on trees and shrubs. They often nest in old wood or hollow stems and will protect their honeydew sources with tenacity, often from the shelter of rolled leaves or under bark.
Big-Headed Ant (Pheidole megacephala)
This highly invasive species uses its powerful major workers (the “big heads”) to defend territory and resources. A key part of their strategy is farming aphids, scales, and mealybugs. Their success in dominating ecosystems is partly due to the reliable carbohydrate source this farming provides, which fuels their aggressive expansion.
Ghost Ant (Tapinoma melanocephalum)
A common household pest in tropical and subtropical regions, the tiny Ghost Ant is also a diligent farmer. They are frequently found tending sap-sucking insects on plants, both outdoors and in greenhouses. They will even bring aphids or mealybugs indoors to infest houseplants, maintaining their herds in a protected environment.
Singapore Ant (Monomorium destructor)
This invasive and destructive ant is a proficient tender of honeydew-producing insects. They are known for their ability to damage electrical wiring and infrastructure, but their ecological impact includes protecting pest insects like aphids, which can exacerbate their negative effects on agriculture and native plants.
Funnel Ant (Aphaenogaster spp.)
These ants are common in forests and grasslands, where they build distinctive funnel-shaped nest entrances. Many species within this genus are known to tend aphids on the roots of plants and low-growing vegetation. They collect honeydew as a valuable energy source while also being important dispersers of native plant seeds.
Long-Legged Ant (Anoplolepis gracilipes)
Also known as the Yellow Crazy Ant due to its erratic movements, this invasive species is a massive-scale farmer. They form supercolonies and tend immense populations of sap-sucking insects, leading to ecosystem collapse on some islands. The vast honeydew input fuels their enormous colony sizes and destructive swarming behavior.
Turtle Ant (Cephalotes spp.)
This genus of arboreal, armored ants is primarily herbivorous, feeding on nectar and honeydew. Many species have evolved close relationships with sap-sucking insects, which they diligently tend on tree trunks and branches. Their flat, disk-shaped heads are perfectly adapted for blocking the entrances to their twig nests, protecting both their brood and their “livestock.”
Amazon Ant (Polyergus spp.)
Known as “slave-making ants,” Amazons raid the nests of other ant species (like Formica) to steal their pupae, which then hatch and work as “slaves” in the Amazon colony. While the Amazons themselves do not farm, their captive workers do. The enslaved ants will continue their innate behaviors, including tending aphids to provide honeydew for the parasitic Amazon colony that holds them captive.