Ants distracted by potato chips in Panama may be forgetting one of their biggest jobs, and scientists say that could slow the seed dispersal plants depend on

Next time you’re out on a hike and drop some chip crumbs on the trail, maybe pick them up. It’s not just about litter. Those crumbs may be silently undoing one of nature’s most important ecological partnerships.

A study published in the journal Biology by Gálvez, Dominguez, Marple, Morris, and colleagues found that when processed food scraps are left near seeds, ants mostly abandon the seeds in favor of the snacks. According to this study, seeds near food waste were removed about half as fast as seeds with no junk food nearby, and this was true in both urban settings and forests.

Ants do more than crash your picnic; they plant forests
Most people wouldn’t think of ants as environmentalists, but they are. Once ants carry seeds to their underground nest, they eat a fatty appendage on the seed, called an elaiosome, and discard the intact seed, effectively planting it. More than 11,000 plant species around the world engage in myrmecochory, or using ants to disperse seeds, according to a peer-reviewed synthesis in Myrmecological News. Some wildflowers, including trillium and bloodroot in the eastern US, depend almost entirely on ants to disperse their seeds. As insect ecologist Clint Penick noted in relation to the new research: plants don't move, so in many cases they need animals to bring them to where they need to be.

How the study worked, and what chips had to do with it
This research originated in a master’s course at the University of Panama, where ecologist Dumas Gálvez taught students to study the effects of urbanization and junk food on ant behavior. The study said they chose potato chips and cookies (without the filling) as the test foods because they are snacks people are likely to take with them while hiking or visiting natural areas.

The researchers conducted three field experiments in Panama. In the first, chip crumbs were placed in a ring around oat seeds. In this study, ants took longer to remove seeds when surrounded by chips, though the team later admitted that the ring may have served as a physical barrier rather than just a distraction. This was remedied in the second experiment, where crumbs were placed in a semicircle to one side of the seed stations: 96 near the chips, 94 near the cookies, and 100 controls. Every five minutes, the researchers recorded how many ants visited the station and how many seeds remained. In this study, both chips and cookies were found to reduce ant-seed interactions, and there was no effect of junk food type or habitat. Overall, more ants visited the urban stations, but similar numbers of seeds were removed at both sites, suggesting that city ants were more easily distracted. One researcher, Lara Dominguez, saw ants descend on crumbs of chips within 30 seconds of them being placed on the ground, long before they would have reacted to seeds.

The third experiment was designed to test distance, with chips placed at 0, 30, and 60 centimeters from the seed stations. According to this study, distraction was as strong at 0 and 30 cm but absent at 60 cm.

This isn't just a Panama problem; it's happening in American cities
Research published in Proceedings of the Royal Society B, titled "Stable isotopes reveal links between human food inputs and urban ant diets," found that the most common sidewalk ant in Manhattan, the pavement ant, showed levels of carbon isotopes consistent with a diet of processed human food. The study found that the more urban the habitat, the more likely ants were to depend on human food scraps. You see this dynamic playing out every day in American parks, trails, and city green spaces.

Little disturbance, big impact
A 2025 paper in the journal Ecology by Karnish and Bronstein at the University of Arizona shows just how finely tuned the ant-seed relationship is. The study shows that ants weigh both the nutritional benefit of a seed’s elaiosome and the effort of carrying it, and that any competing food source can easily outweigh the benefits of the seeds in their behavior. Multiply that by thousands of daily visitors dropping snacks on a single trail, and the effect on plant diversity can add up fast. As Gálvez put it, the effect can “snowball pretty quickly.”

The fix is simple: pack out your food, keep your crumbs to yourself, and let the ants do their thing.