The Foodies Beneath Our Feet—Urban Ants Like Human Food Too

It might be a sad fact, but in our daily lives, the most obvious example of species cohabitation may just be that of humans and ants. Now they're not man's best friend, that's an obvious fact, but these little pests get away with a lot and whether we like it our not they tend to keep coming back. But when researchers looked into the tiny species, they revealed that the reason for their blissful cohabitation may be a lot more similar to why dogs like human homes as well-namely table scraps.

Looking into the colonies of ants taking a bite out of "the Big Apple", researchers with North Carolina State University investigated ants thriving in urban environments utilizing isotope levels to track their diets. And what they found was that most of the 21 ant species living in New York City and along Manhattan's pavement indeed tend to eat a lot of human food when they're at home in the city.

"We wanted to learn more about why some ant species are able to live alongside us, on sidewalks or in buildings, while other species stay on the outskirts of human development," lead author of the study, Dr. Clint Penick says. "This could also help us determine which species are doing the most to clean up our trash."

"Human foods clearly make up a significant portion of the diet in urban species. These are the ants eating our garbage, and this may explain why pavement ants are able to achieve such large populations in cities."

In tracking the amount of Carbon-13 the ants had within their bodies, which was originally incorporated from the food their eat, the researchers were able to find near exact amounts of the isotope consumed, indicating that like humans the ants tended to dine on similar fine dining found in the city. 

However, of course it's the city, so you'd expect to find an exception to every rule. And the ants aren't any exception.

As it so happens, while nearly all of the ant species sampled preferred to wait around for table scraps, one ant species known as Lasius cf. emarginatus thrived instead on the medians in Manhattan and on trees along the NYC streets. Only discovered within the city in the past five years, L. emarginatus is one of few species found amply on the city's sidewalks, but ironically enough, they also appeared to have no preference for human food either.

And Penick says that, "this highlights the complex nature of urban ecosystems and how much we still have to learn about how these species relate to each other and to the environment."

Indeed!