City Ants Love Junk Food, And it’s All Our Fault

We know that many animals have adapted to deal with our sprawling urbanization, but a new study reveals that ants might also be getting in on the act by developing a taste for our waste food scraps and our junk foood.

The research, conducted by scientists at North Carolina State University and published in the journal Proceedings of the Royal Society B, aimed to investigate the eating habits of the most common ant species in our big cities. To do this, the researchers took a sample of 21 different species found in New York City, including those who lived in parks as well as ants we might find on our sidewalks, and tested them in a quite ingenious way: isotope testing.

This is a method scientists can use to look for the presence of particular types of carbon, and in this case the researchers tried to determine which species of ants had the highest presence of a carbon isotope called carbon-13 which we know is linked to the corn and sugar cane that we regularly consume in much of our packaged foods and junk food. If the ants had higher concentrations of this carbon isotope in their system that would mean they were probably eating far more of our food waste than if they didn’t.

Perhaps unsurprisingly, the ant species with the highest concentrations of this isotope was the common pavement ants, as well as well as several species that frequent traffic medians which are the grassy strips between traffic lanes.

“Human foods clearly make up a significant portion of the diet in urban species,” says Dr. Clint Penick, lead researcher in this study, in a press release. “These are the ants eating our garbage, and this may explain why pavement ants are able to achieve such large populations in cities.”

The types of ants that had the lowest levels of the carbon isotope were those who confined themselves to city parks. Interestingly though, the researchers found that one type of ant who lives on traffic meridians didn’t have high levels of this isotope, probably meaning they don’t like our waste food.

The species, known as Lasius cf. emarginatus, is relatively new to NYC and only arrived about five years ago. It is one of the only species that can compete with the pavement ant, but the isotope comparison shows that the newer species doesn’t have much of a taste for our waste food and instead is content to forage among the trees and around its nests for its more traditional foods.

Obviously, by availing themselves of scraps of human food the common pavement ants have a certain advantage, and that’s why this finding is so fascinating. “Humans bring a ton of general resources,” Penick told the Guardian. “The species that can take advantage of these resources the best, sort of wins.”

In the future, the researchers would like to look into whether the pavement ants are just being opportunistic–the food is there so they’ll take it–or have actually developed a preference for human food over their own food. If it turns out that they have formed a preference, this will tell us a number of things, and it could be important for how we manage our urban environments.

Firstly, this would emphasize something this research already illustrates: that, in terms of providing food for ecosystems, humans don’t only have destructive powers as our records might suggest but we can–albeit unwittingly in this case–be a provider of food that can cause species divergence and specialization and, indeed, population increase–because the common pavement ants adapting to enjoy our food is probably what has led to their population boom.

Second, it also suggests a need for us to be careful. We know that other animals such as the urban fox, squirrels, rats, pigeons, and several other species, have adapted to urban life and now come to rely on our food waste and junk food in order to survive. When we attempt to clean up our act, get our streets clean, and embark on health campaigns to change the kinds of foods we eat, we do so primarily for our own sake. However, this research emphasizes that we are tied into a complex ecosystem and that our changes to the environment can have unintended consequences.

As such, this research gives us a glimpse into which ants are benefiting from our current habits and which ones are keeping themselves to themselves, which is vital data in itself if we should ever need to embark on population control efforts. In the meantime though, it’s nice to know that at least some species might be benefiting from our food waste problem.

Photo credit: Thinkstock.


Siyus Copetallus
Siyus Copetallus2 years ago

Thank you for sharing.

Melania Padilla
Melania Padilla2 years ago

Of course it is our fault! Who else invented junk food but us? Like the addiction of wild bears to our bad food :(
Nice going, again, humans.

Ruhee B.
Ruhee B2 years ago

What on earth are ants and other urban wildlife meant to eat? As the song goes "we've paved paradise and put up a parking lot" The natural habitat where these animals lived and foraged for their natural food has all been taken over by humans. They were here long before us and have every right to be here - I do hate our species for it's selfishness, greed and arrogance! Oh and the only species which seriously needs "population control" is us!!!!

Mahmoud Khalil
Mahmoud Khalil2 years ago


Jan N.
Jan N2 years ago

The only ants I have live outside by the driveway. Or probably in the back yard, but I don't go looking for them.

I'm like Anne K., I used to give sugar to the ants when I was a kid. I would also fill a jar with dirt and capture ants, and they would dig tunnels and create an "ant farm". They got sugar also, and the occasional dead bug I either found or killed just for them. I can't do that now, but as a kid I could. I also used to catch spiders and put them in a jar with a propped up stick and they would make a web and I would catch bugs (usually flies) for them to eat. I wanted to be an entomologist, but when I got older I learned most entomologists got jobs trying to find ways to kill bugs, so I ditched that idea.

Anne K.
Anne K2 years ago

OMG! It's MY fault! I never thought of this before. When I was a little kid, I was fascinated by ants (maybe I still am - fascinated with nature in general) I used to take teaspoons of white granulated sugar and white bread crumbs out to the ants to watch them carry the "food" to their mound. I would lie on the ground and observe the ants. I thought I was doing them a favor by feeding them.

Margaret Goodman
Margaret G2 years ago

This article was really interesting, and it got me to wondering.

The pavement ants are eating more corn and cane sugar than do other ants.

So, are the pavement ants less healthy than the other ants?
Do the pavement ants have more diabetes than the other kinds of ants? Can ants even be diabetic?
Are the pavement ants becoming obese? If so, how does obesity work with the exoskeletons of the ants?

I'm not expecting answers, but there might be a research topic there for an entomologist...

Are the pavement ants being affected by all the GMO corn and sugar beets?

sandra vito
Sandra Vito2 years ago


Muff-Anne York-Haley

This is kind of sad!