Ants Can Get Distracted by Cookies, Chips and Other Junk Food. Here’s Why That Could Be a Problem for the Environment

The insects enjoy snack crumbs, but new research shows that this unnatural food source can divert them from one of their most significant roles: dispersing plant seeds

Katie Cottingham | Freelance Writer

June 16, 2026 12:15 p.m.

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Summer is a time for picnics and barbecues, but a few uninvited guests occasionally crash the party. These guests—ants—have developed a taste for the same processed foods that humans enjoy. In urban settings, ants that have the most contact with humans have the highest levels of carbon isotopes, which are associated with ingredients used in processed foods. The finding suggests that ants living with humans tend to eat their snacks. City ants also forage more during the day than forest-dwellers, perhaps to increase their chances of snagging food crumbs that fall as humans nosh.

A study published in April in Biology now shows that junk food can have broader implications for ants: It may distract them from their important job of dispersing seeds.

“Many ant species play a major ecological role by transporting and burying seeds, which helps plants spread and grow throughout the forest,” says ecologist Emily Marple, a global sustainability fellow at the Smithsonian Tropical Research Institute in Panama, who was involved with the recent study.

Some ants are attracted to seeds with a structure containing fats and proteins, called an elaiosome. Ants take the seed to their underground nests, and after they’ve eaten the elaiosome, they discard the intact seed, which can grow into a plant. Ants can also eat the seeds themselves, and will gather them to transport to their nests. However, they sometimes drop the seeds along the way or set them aside and neglect to eat them.

“We wanted to see how human activity, specifically food litter, affects seed-dispersal behavior,” says ecologist and global sustainability fellow Lara Dominguez, who also worked on the project.

The idea for the study took shape during a master’s course that animal ecologist Dumas Gálvez taught last year at the University of Panama. “We started talking about several topics, such as how urbanism affects ant diversity and how junk food in cities could influence the diet of the ants,” says Gálvez, who is a professor at the university and a research associate at the Smithsonian Tropical Research Institute. Although he led the study, Gálvez encouraged the students to devise the experiments and analyze the data themselves.

The students, along with Dominguez and Marple, eventually developed the topic into a full-fledged scientific study with three separate experiments looking at whether the availability of potato chips and cookies would change ant seed-dispersal behavior. The team reasoned that they would probably observe one of two outcomes: The ants might remove fewer seeds from a pile that was placed near processed food, because they were distracted by it. Or seed transport might increase if more ants were drawn to the site overall by the junk food but not distracted by it.

Lay’s potato chips and Oreo cookies (minus the filling) were chosen as the snack foods for the experiments, “because they represent the kinds of snack foods people commonly bring while hiking or visiting natural areas,” says Marple.

In their pilot experiment, the researchers set up 126 seed depots on the university grounds near buildings where students and staff commonly walked. The seed depots had as their foundation a round petri dish lid that was pushed down into the earth, so the smooth plastic surface was level with the ground. For half of the depots, the team placed oat seeds on top of the lid then sprinkled potato chip crumbs in a circle around it. The other depots were controls with seeds only, not near any junk food. The researchers counted the number of seeds at each depot over time to measure seed-dispersal activity.

They found that ants removed seeds more slowly when the seeds were within a ring of chips. “But then we realized that the experimental design was not ideal, because maybe the chips surrounding the seeds were too much of a physical barrier for the ants,” says Gálvez.

In the next experiment, either potato chip or cookie crumbs were placed in a semicircle along one side of a seed depot. Now, 96 seed depots were near chips, 94 were near cookies and 100 were controls. The researchers set up the experiment both on the university grounds, which is an urban site, and in a forest at Soberanía National Park. They counted the number of seeds remaining at the depots as the experiment went on, and this time, they counted the number of ants that were crawling on the seed depot lid every five minutes.

The chips and cookies significantly decreased the number of interactions that the ants had with the seeds. “Essentially, the ants were distracted from the seeds by the processed foods that we left out,” says Dominguez. The type of junk food and habitat made no difference in the number of seeds that were removed.

Overall, more ants visited the seed depots at the university site compared with the forest site, but similar amounts of seeds were removed at both locations. Gálvez says the data suggest that urban ants were also more easily distracted; otherwise, more ants visiting the university depots would have resulted in more seeds being removed.

Dominguez saw junk food make an almost immediate impact during the second experiment. “I was surprised to see how quickly the ants reacted to us placing chip crumbs on the ground,” Dominguez says. “Within 30 seconds of putting the crumbs down, there would suddenly be many ants. They wouldn’t react as quickly to the seeds in my experience.”

The final experiment tested how distance affected ant behavior. In 12 seed depots, potato chip crumbs were placed right up against the petri dish, and for another 12, they were placed either about one foot or two feet away. Ants were distracted to the same extent if chips were next to or a foot away from seeds, but the effect waned at two feet.

Gálvez plans to replicate the experiments and test in multiple urban and forest locations, and he hopes to investigate the effects of a junk food diet on ant physiology. Further, these experiments were performed during the day, and Gálvez wants to see how nocturnal ants would behave.

Although ants transport them, oat seeds don’t have elaiosomes. Clint Penick, an insect ecologist and assistant professor at Auburn University who was not involved in the study, says, “It would be interesting to see if the same results hold up for elaiosome-style seeds like trillium and bloodroot as they do with the oat seed.”

Ants can become so distracted by junk food that they neglect to disperse plant seeds, but the big question is: How much does this matter to real-world ecosystems?

“Plants don’t move, so in a lot of cases, they need animals to help them get where they need to be,” says Penick.

Ants distracted by junk food could shift the balance in ecosystems and reduce the number of plants in certain environments.

“This seems like it is on such a small scale that it might feel insignificant, but in locations where there are thousands of people every day dropping leftovers, it definitely could have an impact on the dynamics of dispersal, especially for those plants that depend on ant activity for their dispersal,” says Gálvez.

Dominguez agrees: “I think the most important takeaway of the study is to be mindful of how even small amounts of human disturbance can have an effect on animals and the broad-ranging ecosystem services they provide. It can snowball pretty quickly.”

Katie Cottingham | Read More

Katie Cottingham is a writer covering biology, medicine, chemistry and materials science. Her work has been featured in Scientific American, Science, Chemical & Engineering News, INFORM, EpiGenie and more.