The ant that's taken over Manhattan

MARY LOUISE KELLY, HOST:

Frank Sinatra famously said that if you can make it in New York, you can make it anywhere. Well, there is one recent immigrant to New York that is making it big time. It is an ant, a dark brown ant with a red midsection. It has become the top of the heap, as the song goes, and it is starting to spread beyond the city's borders. NPR's Nell Greenfieldboyce reports that this ant's success is both surprising and worrying scientists.

NELL GREENFIELDBOYCE, BYLINE: This ant showed up in Manhattan just over a decade ago in 2011. It was clearly a new arrival because it hadn't been found when researchers surveyed the city's ants a few years before. This mysterious newcomer briefly made headlines. The New York Post called it the ManhattAnt.

IZZIE KAPLAN: So I got one in here. There's a bunch of debris in here, but you can see it climbing up the side.

GREENFIELDBOYCE: Izzie Kaplan holds up a clear plastic vial so I can peer in.

KAPLAN: It has the red thorax, so that's how you can tell that it's the ManhattAnt.

GREENFIELDBOYCE: She's a student at Fordham University in New York City, where she works at an insect research lab. We met up a few blocks from Central Park. She took me over to a concrete wall and lifted up some vines.

KAPLAN: You can see one crawling.

GREENFIELDBOYCE: Yeah, it just disappeared.

KAPLAN: Yeah.

GREENFIELDBOYCE: You got to be pretty fast to get these guys, I guess.

KAPLAN: Yes, they're very fast, and that's...

GREENFIELDBOYCE: Besides being speed-walkers, these ants also like to climb, startling New Yorkers who aren't used to seeing ants up in high-rises. ManhattAnts seem to be everywhere - crawling on a trash can, near a metal grate in a sidewalk, under a gazebo. Clancy McCann is another Fordham student. I watched her use a contraption with a long, plastic tube to suck ants out of a big flower pot. She says these ants don't sting.

CLANCY MCCANN: But they are very aggressive towards other ants, and you will see them carrying other ants' bodies across, like, the pavement, and it is crazy.

GREENFIELDBOYCE: So will the ManhattAnts be a problem for native ants or anything else that lives around here? Clint Penick would love to know that. He's with Auburn University, and he worked to conclusively identify this ant. It turns out to be one that normally lives in Europe, which shocked an ant expert there.

CLINT PENICK: He was like, are you sure - Lasius emarginatus? He was like, they're not even really dominant in any European area. They're not known as an urban pest. And so it was quite surprising that this species was the one that was taking over Manhattan.

GREENFIELDBOYCE: And it is definitely taking over. Penick and some colleagues just published their research in the journal Biological Invasions. It shows that the ManhattAnt is vying with the so-called pavement ant for being the most common ant in the city, and it's no longer confined to its namesake island. It's moved north into the Bronx, south into Long Island and across the Hudson River into New Jersey, spreading at a rate of a mile a year.

PENICK: We predict that they could expand as far north as Maine and as far south as Atlanta, Ga.

GREENFIELDBOYCE: And what's concerning is that this ant does share some habits with invasive ants that have caused troubles in the past. Samantha Kennett is a Ph.D. student at Clemson University. She says this ant likes to eat the sugary poop of aphids and scale insects. The ants will protect and herd these plant pests, increasing their numbers, which may be bad news for the plants.

SAMANTHA KENNETT: I think it would be really interesting to see how, in the long term, the ManhattAnt could have effect on trees in New York or anywhere that they are invading.

GREENFIELDBOYCE: Ants are tiny but so numerous that their activities can wreak serious havoc in a new environment, sometimes in unexpected ways. One study in Kenya showed that invasive ants triggered a chain of events that led to lions eating fewer zebras. So far, no one has noticed any major changes in the wake of the ManhattAnt's arrival, but the ant hasn't been here that long, and people have only recently started looking. Ellen van Wilgenburg is a researcher at Fordham University who studies ants as well as the spotted lanternfly. She says when the spotted lanternfly hit the East Coast, it got a lot of public attention.

ELLEN VAN WILGENBURG: Like, so many people were telling me, like, this is terrible. We need to get rid of this species.

GREENFIELDBOYCE: Meanwhile, she says, the ManhattAnt has been crawling all over the city, largely unnoticed under millions of feet.

WILGENBURG: It's probably more abundant even than the lanternfly, and no one knows.

GREENFIELDBOYCE: Researchers are hoping the public will help them track this ant as it moves into new areas. That's why they set up a special Project ManhattAnt page on the iNaturalist website. People can upload photos to show exactly where this ant is and what it's doing. Nell Greenfieldboyce, NPR News.

(SOUNDBITE OF SONG, "THEME FROM NEW YORK, NEW YORK")

FRANK SINATRA: (Singing) Start spreading the news. Transcript provided by NPR, Copyright NPR.

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