[The following is a guest post by ant scientist Rob Dunn]
How a group of 19-year-old undergraduate students discovered a common but unnoticed ant species in plain view in New York City.
This story of discovery has a concrete beginning. I remember the day I got the call. I had just returned from a hiking trip in one of the oldest forests in Great Smoky Mountains National Park and the phone rang. It was an invitation to help lead an expedition into the dirty bowels of New York City.
I rarely turn down an opportunity and yet New York inspires more anxiety in me than pleasure. I grew up as a country kid, most comfortable in and among trees. Sure, Manhattan has trees, but it also has a way of making them seem dwarfed beneath the shade of buildings, as though each and every one were part of some oversized diorama.
The call was from an old friend, James Danoff-Burg, then at Columbia University, and so I listened. James wanted me to help make “big biological discoveries” in New York City’s wildest parks. I said I would come but I didn’t think we would find much. I was wrong.
James and I went on our first odyssey together in the desert Southwest of the United States when he was a graduate student at the University of Kansas and I was still a 19-year-old undergraduate student at Kalamazoo College. I helped him search for reclusive monsters called sceptobiines that live hidden in the tunnels of ants, much the way rats live in the subway tunnels of New Yorkers. During that work, we were nearly shot by a farmer, stuck on a talus slope with no way down, and trapped inside a tent as a skunk walked over our feet (2 out of 3 of those were my fault, but I digress). James promised this New York expedition would be straightforward. If memory serves, that is also what he had promised when we went to the southwest.
The New York expedition was part of a course called “The Frontiers of Science” designed to expose every new student in Columbia College at Columbia University to how neuroscientists, astrophysicists, geologists and biologists approach the world. Our job was to show them the frontlines of biology by having them make discoveries in the city. The astrophysicists could point to the stars, James said, “but what if we took the students to the least disturbed parks in the city and had them point to life forms no one knew were there!” James wanted to send Economics, English, Political Science, African American Studies and even English majors, English majors mind you, to document the wild life of Manhattan. It would be, he argued (and he was right), one of the first major studies of the biodiversity of America’s biggest (he probably said “greatest”) city.
While James imagined big discoveries, I found it easier to conjure disasters. I worried we would not find anything interesting. Worse, I worried about the students. These were urban New Yorkers. Many of these kids had probably never seen a wild animal larger than a rat (though, I suspected, they had probably seen some pretty big rats). I pictured Gucci bags snagging on tree branches, black, high heels stuck in the mud, leaf-litter samples filled with equal parts broken glass, poison ivy, and needles. Then, of course, there was the issue of the bodies. As everyone who has seen Law and Order knows, when you push aside the leaf litter in the parks of Manhattan you almost always reveal bodies.
When I arrived in New York I found James in a classroom at Columbia in front of one of the groups of students that we would lead out into the woods. All told, James would lecture to 550 students, each and every new undergraduate, before sending them off, graduated out into nature. James lectured to this particular group about conservation, discovery, the sex lives of ants (tawdry), and the frontier at which they found themselves. He explained that the ants and other species of the city performed services. Without the ants and dung beetles, New York would be knee deep in dog poop, cookie crumbs and dead pigeons and roaches. “These are the undertakers, farmers, and predators that keep the city alive.”
When James was done, each student was handed the tools necessary for Ivy-league success, or at least success out in the ivy. Each group had a plant identification guide, a sheet on which to put leaf litter in order to search for ants and an “aspirator,” a device into which they would suck any ants they saw. Aspirators consist of a jar and two flexible tubes. One tube leads from the ant to the jar, the other tube leads up between the lips of whoever is using it. When an aspirator is working properly, a piece of filter paper keeps the ants from being inhaled. When one is not, well, you get to learn the taste of ants. Some taste like candy. Others taste like acid. The equipment was not fancy—insufficient for astrophysics—and yet to do good biology, it was enough.
I decided to start off by going to Inwood Hill Park with one of the groups. Other students had already been to Central Park and Riverside Park. Inwood seemed more remote and untrammeled. My group and I descended the 10 floors of the building and went outside. Now we would trek to the field site. When I have worked in forests elsewhere—say Bolivia, Ghana or Australia—getting to a field site can be a real challenge, long hikes, wet socks, blisters, boils and bad buses. In New York, we took the subway.
The day seemed a little too chilly for discovering many insects. I wanted the students to find something, even if it wasn’t an actual discovery, at least some species they had not noticed before, something that was new to them if not to New York. But it was early fall and a little late in the season for ants. More to the point, Manhattan is so incredibly urban, so impacted relative to what once bloomed in the city’s absence (towering Chestnut trees, white tail deer, bear and wolves) that it was possible the ants would have decided to pack it up for wilder shores. Inwood Hill Park was our best hope.
Once near Inwood, we exited the underground and headed for the park entrance where the teaching assistants gave one last lesson. I heard someone say, as I walked ahead, “If you see poison ivy don’t touch it. Wipe your hands in the dirt, if you do touch the poison ivy. If there is broken glass in your plot, let us know, and we will find you a new plot.” In groups, students sifted leaf-litter onto white sheets and, as quickly as they could, sucked up what scurried away. Sure enough, not all the aspirators were working. Somewhere someone yelled, “Help, I think I swallowed an ant!”
Inwood Hill Park is big enough to have secrets. It is where I would go to avoid detection if I were a coyote or a rare ant species. It is where bald eagles were recently released as part of a reintroduction project and where some of the largest trees in the city can be found. The biggest trees, some of them hundreds of years old, cast shade over an understory of trails, shrubs and a great density of human history. The Lenape, the Native Americans who lived in Manhattan when Europeans arrived, built encampments where the park now stands. Inwood’s forest, in other words, is big and old enough to have some secrets. As we climbed up the trails, we could see children down below us playing baseball to our east and to the west we saw the Hudson. I was beginning to feel more at home. I started turning logs.
For me, and I suspect many biologists, turning logs is therapy. Turn a log and you reveal a new world. Tunnels lead from under logs into another universe of smaller life forms. You never know what is beneath a log or rock until you turn it. Sometimes a salamander, other times a snake, nearly always an ant, pill bug (AKA woodlice, rolly pollies and isopods) or other small, mysterious form. As I began to turn over logs and rocks in the park, I nearly forgot I was in Manhattan.
What I saw first were the worms. Worms were everywhere—wriggling worms, dead worms, great piles of worm castings and poop. But there weren’t just worms, there were also tokens of city life—cigarette butts, bits and pieces of ritual paraphernalia, a pink feather, an elastic waste band—and then, beneath the third log I turned, ants.
The first ants I saw were citronella ants of the species Lasius claviger, a shepherd ant. They carry scale insects and aphids from one root to another. They kill some of these cattle to feed their babies, but most are tended to with what passes for care until they can be milked for their sweet honeydew. Just why these ants produce and smell like citronella remains a mystery. Also a mystery is where their queens hide. Although citronella ants can be very, very, common, no one appears to have ever found their queen, at least not in a mature colony. She is down there, no doubt, fat and fertile, but well hidden, a discovery waiting to be made even in New York. With those ants, I was rolling. I yelled to the nearest students to come see. One came to look and ask questions. It was the English major, the one who had earlier given me a look that seemed to say, “I am an English major and I am going to be a great writer, please let me go back inside.” She was smiling. Success! I was off, looking for more logs.
As the day progressed, I found more ants. I turned more logs. I peeled back bark. I broke open acorns. I was happy. I had found the real societies of Manhattan –-or at least the ones in which I was most interested—and was able to share them with students who would never have seen them otherwise. Here were bulbous species of Formica ants, polygamous odorous house ants (Tapinoma sessile), and more, even the long-legged Aphaenogaster rudis, carrying off the head of the beetle (for the record, the only dead body we found in the park). By the end of the day, the students, teaching assistants and I had collected 13 ant species, individuals of thirteen lineages, each older than humanity.
I hoped the students were happy. They seemed to be. I heard laughter and even some outbursts of unprompted joy. One guy mentioned he wanted to come back and look some more another day. Two women were talking about how to tell a spider from an ant and then as I walked past one group I heard “How are we going to get the worm in the jar.” “Suck it up” “Expletive!” I thought about telling them that they were only supposed to collect ants, but who am I to judge. I just hoped their aspirator had a filter.
That might have been the end of the story. In some ways, it was an end, at least to the students experience that day. It was a good day, a day that mattered, but there was to be more.
Most people on Earth now live in cities. If they are going to care about and understand nature it is going to have to be urban nature, at least as a point of departure. This concept has been called the pigeon paradox, where the paradox is that the conservation of wild things, like tigers, can depend on the ability of urban-living folks (who have most of the world’s power and money) to care about the species around them, be they red-tailed hawks, ants or even pigeons. If there was a lesson from these students, it was a hopeful one. They could be shown the way toward caring about or at least paying attention to the life around them. I thought about all of this as I rode the subway back to Columbia where I sat down with James to identify the ants the students had found. As James stared out the window at the lights city, I looked through the microscope at the details of a smaller world.
At least initially, there was no true rare gem. There were winter ants (Prenolepis imparis), which I had already pointed out to the students. Winter ants forage only in the cooler times of the year when they can avoid competition with tougher ants. They are cool-season pacifists. They make up for what they miss by storing sugar-water, a sort of honey, in the abdomens of some of their sisters. These sisters serve as a living larder for the hot months when on the streets above children are cooling down by running through the fire hydrant’s spray. Cool, but not new.
There were other interesting ants too, but predictable ones, species we were not surprised to find. Then there was a species of the genus Nylanderia, the clan of the crazy ants. There are a handful of Nylanderia species that might be found in New York. That one of them might be common was, again, not big news. But as we looked at this one, something about it was strange. It was not one of the native species. WAIT! Here was something big, maybe.
This Nylanderia species was something neither of us had seen before. It was, it seemed that day and we later confirmed, a Japanese species, Nylanderia flavipes. At the time, this species does not appear to have been reported from Manhattan or even from New York. What was more, it was the most common ant the students had found. It was in nearly every patch of leaf-litter sampled in every park. In other words, the students had not discovered a new rare species in the city. They had discovered a new common one, a species no one appears to have really realized was there and certainly that no one knew was so widespread. Here it was, a discovery made by English majors, History majors and every other student that entered Columbia College in 2004, a discovery that anyone could have made, but no one did. Millions of people must have sat on, stepped on and inadvertently fed these ants without paying quite enough attention. We tend to assume common species are well known, but very often, it seems, they go unnoticed and ignored (see truck stop discovery). I will hazard there are as many individuals of this ant species in Manhattan than there are human New Yorkers.This particular species is introduced and so bad rather than good news and yet, either way, a discovery.
Since the frontiers course, I have gone back to Manhattan with some frequency. It seems like a more comfortable city now that I know it has wild places and wild species left to find. If you happen to see me there, you will be able to spot me among the tourists craning their necks to look up at the buildings. I will be the one looking down.
The first time I went back to see the ants was a year or so later, when Marko Pecaravic, a Croatian student, began a masters degree with James. Marko studied the ants on street medians on Broadway and Park Avenue. There, he found, in addition to many, many, individuals of Nylanderia flavipes, another species no one knew was present, Pachycondyla chinensis, also from Japan.
Then, earlier this year, it was my turn to call James. He was not living in Manhattan any more, but I wanted to know if he was up for an expedition to New York to find something new. He was. We went back to Inwood Hill Park and then Marko’s medians to look for ants. James and I have searched for ants on several continents together, but nothing, he showed me, is quite like looking for ants in Manhattan. As we paused to joke in one median, a horn honked. House sparrows rose up out of one of the planted trees. The subway vibrated beneath us. And all around us, ants, bees, wasps and thousands of other species moved about their lives, the other 99% who have occupied Wall Street and the rest of New York. We will go back again. There is so much to see in Manhattan, especially when you are looking at the ground.
I can’t help but wonder where those 550 Columbia freshmen went. They should all have graduated by now, out into the world of their chosen professions. I hope that at least a few of them still remember that the big apple is riddled with life. It is one of the most highly observed cities in the world and yet so unknown that if any of them were to choose to, they could go outside right now and do more science. Doing real science, I learned in New York, and I would learn again each time I work with students or the public, is for everyone. As for New York, it is for the birds, but also the ants and other insects for everyone of us who wants the streets clean and the flower pollinated, that is a good thing.
Back in the medians, James and I did not find anything terribly new on our most recent trip to Manhattan (except for science writer Carl Zimmer). We must have needed the students to make big discoveries, a possibility confirmed when three of my students from North Carolina State University—Britné Hackett, Brian Parham, and Benoit Guenard—went to Manhattan to do more work on ants. They too went to the Broadway medians but then also to Riverside Park where, lo and behold, they found a new ant species, apparently not recorded in North America before. We are keeping that species a secret until we confirm its identity for sure. They also found thirty other species, some of them the same species the Frontiers of Science class and Marko found, but many of them new, at least to Manhattan, and in some cases to the state of New York.
In 2005, the field expedition portion of the Frontiers of Science was cancelled, but its mission, to help everyone do and understand science and the living world, lives on1. The course was part of what inspired me to work with Andrea Lucky to figure out a way to get students all around the U.S., not just those from Columbia University, to be able to get out into their own cities and see the ants. Now they can. The School of Ants project (www.schoolofants.org), allows anybody, anywhere in the U.S. (and soon more parts of the world) to sample ants. If English majors can discover the most common species in Manhattan, imagine what lurks in Chicago, Tucson and Miami, to be found for the first time by whoever goes to look. We can help you to know what you find, but your task to go out searching, looking for ants, but also whatever other species crosses your path or emerges like a revelation from under a stone.
Meanwhile, in Manhattan we still don’t know what lives outside the medians and parks of the city. Who lives under the cement, or crawls under your door? No one knows, so if you do live in New York, make a kit, put some cookies out and wait, for something to come marching, though just what it will be no one is sure.
1-In multiple ways… I’m now collaborating with Sergios-Orestis Kolokotronis, at Barnard College, now plans to lead a course this spring in which he will take his students out to sample ants and study the extent to which they are genetically isolated and diverging between Manhattan’s different patches of green and grey. Elsewhere, Jason Munshi-South, whose work includes a study of the population genetics of the mice of Manhattan (see Zimmer’s article), is working with his students at CUNY to sample ants too using the schoolofants protocol.
Rob Dunn (RobRDunn on twitter) is a science writer and biologist in the Department of Biology at North Carolina State University. His enthusiasm about the wild life in cities like New York is part of what led him to write his most recent book, The Wild Life of Our Bodies, about the species everywhere around us. The Wild Life of Our Bodies, explores how changes in our interactions with other species, be they the bacteria on our skin, forehead mites or tigers, have affected our health and well being. Rob lives in Raleigh, North Carolina with his wife, two children, and lots of strange, small, species.