Scientists Discover 'Cleaner Ants': One Species Grooming Another in the Wild

A paper published in Ecology and Evolution in April 2026 describes what appears to be the first documented case of one ant species grooming another in the wild.

Entomologist Mark Moffett, a research associate at the Smithsonian's National Museum of Natural History, observed small cone ants climbing onto much larger harvester ants in the Arizona desert and grooming them, including reaching inside their open jaws.

What Moffett Observed

The interactions took place near a research station in Arizona's Chiricahua Mountains. Moffett noticed harvester ant workers (Pogonomyrmex barbatus) standing unusually still, which immediately stood out. Zooming in revealed why: tiny cone ants from an undescribed Dorymyrmex species were licking and nibbling all over them. He initially assumed aggression, but the harvester ants were clearly cooperative. They visited the cone ants' nests willingly, then held still while the smaller ants groomed them.

"Given the usual tendencies of ants, I first assumed that I was observing aggression," Moffett said. "But the larger ants seemed to seek the attention of the smaller ants by first visiting their nests and then allowing the small ants to lick and nibble all over them." He documented more than 90 of these interactions over several days. Sessions ranged from around 15 seconds to more than five minutes. When the harvester ants had enough, they shook the cone ants off, sometimes hard enough to flip the smaller ants onto their backs.

What Both Species Get From It

The most obvious parallel is to cleaning stations in marine environments, where small fish like cleaner wrasse remove parasites from much larger animals. Scientists believe something similar is happening here between these two ant species, though the details are still being worked out.

For the cone ants, the likely payoff is food. They appear to collect small, energy-rich particles from the harvester ants' bodies, possibly fragments from the seeds the larger ants spend their days collecting. This would explain why cone ants placed near dead harvester ants showed no interest at all: whatever they are after is only present on a living, active ant.

For the harvester ants, the benefit looks like hygiene. Ants invest heavily in grooming within their own colonies to remove debris, fungal spores, and pathogens. The cone ants, with their finer mouthparts, may be able to reach places the harvester ants simply cannot clean themselves. Researchers also point out that at least one Dorymyrmex species produces antifungal and antibacterial substances, raising the possibility that the cone ants actively contribute to the health of the ants they clean.

Why This Matters for Ant Keepers

If you keep ants, this discovery adds something new to a behavior you have probably already watched hundreds of times. Ants in a formicarium groom each other constantly, and it serves real purposes: clean ants stay healthier and colonies tend to be more stable. This research shows that the same instinct can, under the right conditions, operate between completely different species.

It is also a good reminder of how much ants depend on what they eat and what they encounter as part of their daily routine. Keeping your colony well-fed supports those natural hygiene behaviors you see in the nest. Our guides on what ants eat and feeding your ants protein cover the basics of giving your colony what it needs.

"All kinds of amazing discoveries are still there to be made outside of the lab," Moffett said. "Finding new species and behaviors in nature often requires us to pay close attention to the small things." Finding this in ants, after so many decades of study, is a good example of why fieldwork still matters.

Sources

Moffett, M.W. (2026). The First Cleaner Ant? A Novel Partnership in the Arizona Desert. Ecology and Evolution.

Smithsonian Institution. (2026). Smithsonian Research Associate Discovers Ants Assemble to Be Picked Clean by 'Cleaner' Ants. Smithsonian Newsdesk.