Smithsonian research associate discovers ants assemble to be picked clean by ‘cleaner’ ants, a novel insect behavior
The interaction, which resembles how cleaner fish pick at other species of marine fish, was observed in the Arizona desert
Smithsonian
image:
In the deserts of southeastern Arizona, several cleaner ants tend to a harvester ant by licking tiny particles off the larger ant's body.
view moreCredit: © Mark Moffett, Minden Pictures
In the deserts of southeastern Arizona, harvester ants congregate with serrated jaws agape outside the nests of much smaller cone ants. However, the nests’ inhabitants are not threatened. Instead, they crawl all over the harvester ants and lick and nibble their body surfaces—the first known example of an ant that cleans a much larger ant species.
The unusual behavior, described for the first time this week in the journal Ecology and Evolution, was observed by entomologist Mark Moffett, a research associate at the Smithsonian's National Museum of Natural History. He compares the new species of ant to small marine species of fish that remove dead skin and parasites from larger fish, at times even predators like sharks.
“This new ant species is the insect equivalent of cleaner fish in the ocean,” Moffett said. “The potentially dangerous harvester ants even permit the visitors to groom between their open jaws.”
Moffett, who specializes in studying the social biology of ants and other animals, observed the behavior during a visit to a research station in Arizona’s Chiricahua Mountains. While enjoying his coffee early one morning, Moffett watched worker harvester ants (Pogonomyrmex barbatus) spread out from their nests to collect seeds. He noticed a few of the red-colored insects appeared frozen in place, an odd behavior for the constantly roving workers. Using his camera, he zoomed in further and discovered that the halted harvesters had tiny cone ants on 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.”
Over the course of several days, Moffett watched at least 90 harvester ants being tended to by the smaller cone ants, which represent an undescribed species in the genus Dorymyrmex. He photographed many of these interactions, documenting the strange behavior step-by-step.
First, the harvester would approach a cone ant nest and stiffly stand high on her legs with her mandibles open (all worker ants are female). Usually within a minute, a cone ant would emerge, climb onto the harvester ant and begin inspecting the larger insect. Over the course of the interactions, some of which lasted less than 15 seconds while others surpassed five minutes, as many as five cone ants would crawl aboard and use their tongue-like mouthparts to lick all over the harvester ant, including between her serrated jaws. For her part, the harvester ant tolerated the attention without biting. When she was ready to move along, the harvester ant bucked the smaller ants off so forcefully that she often ended up on her back before scurrying away.
A Novel Behavior
Moffett had never seen or heard of a behavior like this in any other ant or insect. The closest analog occurs in the ocean when large marine fish seek out distinct “cleaning stations” where smaller “cleaner” fish and shrimp eat dead skin particles and parasites. Like the cone ants, some of these cleaner fish even feed inside their jaws.
Moffett has yet to establish what each species of ant gets out of the interaction. He posits that the cleaner ants are likely consuming calorie-rich dust-size morsels they “squeegee” off of the harvester, potentially the flakes coming off the seeds that the larger ants eat. Still, the cone ants were only interested in licking living harvester ants and did not clean frozen specimens Moffett placed outside of their nests.
The interaction may also benefit harvester ants. While harvester ants are known to groom each other to remove parasites, spores and debris, Moffett speculates that the much smaller cone ants may be able to clean areas of the worker ants’ body that their larger nestmates cannot reach. To determine the benefits, Moffett suggests that future investigations focus on whether the cone ants’ cleaning reduces infections in harvester ants or whether the behavior improves the microbiome of either species.
Moffett thinks the new work highlights just how important it is for researchers to keep their eyes open—and cameras ready—when observing animals in the field.
“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—including the ants.”
About the National Museum of Natural History
The National Museum of Natural History is connecting people everywhere with Earth’s unfolding story. It is one of the most visited natural history museums in the world. Opened in 1910, the museum is dedicated to maintaining and preserving the world’s most extensive collection of natural history specimens and human artifacts. The museum is open daily, except Dec. 25, from 10 a.m. to 5:30 p.m. Admission is free. For more information, visit the museum on its website, blog, Facebook, LinkedIn and Instagram.
# # #
Journal
Ecology and Evolution
Method of Research
Observational study
Subject of Research
Animals
Article Title
The First Cleaner Ant? A Novel Partnership in the Arizona Desert
Article Publication Date
13-Apr-2026
No comments:
Post a Comment