At the end of May, when she traveled to New Orleans and New Jersey, she left her apartment on East 81st street clean. She was angry when she found the ants in her house.

She said there wasn't anything to be had. She lived on the 6th floor and had never seen ants before.

In high rises, ants prefer soil-filled parks and yards. Scientists who study ants say a species from Europe has recently made the city its home and is now being found in living spaces several stories above the street.

A witness on the r/Brooklyn forum wrote that he woke up to ants in his living room. I live on the third floor and have never had a problem with insects. The 25th floor of the apartment building had ants.

"They just showed up one day, and I've never seen an ant in my life," said the woman who has lived in the same apartment for eight years. The neighbor had them as well. She sent three photos of liquid ant baits. Each was full of dead ants.

The reporter has lived in New York for decades and had never seen ants before. One day in May, they were up on the fifth floor of an elevator building in New York. They were seen parading across the living room. They congregated under the couch.

People living in the quiet woods of Westchester or the sleepy suburbs of New Jersey may think that having ants is something that happens to other people. In an urban environment, ants can be difficult to understand. The graduate student in Dr. Clint Penick's social insects lab is excited about the project. She studies ants.

ImageThe ManhattAnt is a European immigrant and possibly arrived in New York by ship.
The ManhattAnt is a European immigrant and possibly arrived in New York by ship. Credit...Evelyn Freja for The New York Times
The ManhattAnt is a European immigrant and possibly arrived in New York by ship.

Ms. Kennett is studying an ant named Lasius emarginatus. The ant is not native to the United States and may have arrived by ship. In New York, it was first seen. There were lots of other ants in a previous survey, but not Lasius emarginatus.

The Lasius emarginatus, which has a reddish-brown thorax and a dark brown head and abdomen, has been thriving in New York over the last ten years.

Ms. Kennett's research focuses on understanding how this ant, who is now one of the most common ants in New York City, has been able to survive in the city. She found Lasius in trees all over Broadway and Midtown. They were located in Times Square. "They are all over the place."

The upper floors of apartment buildings are included. The ManhattAnt is mobile. She said it forages in trees. It goes a long way. They found it in European buildings. It seems to be scaling the structures of New York City.

Ms. Kennett was able to confirm the presence of Lasius emarginatus in the photos. Ms. Guhl didn't have photos, she couldn't tell the species that visited, and she had to dispose of the corpses. "I wasn't paying much attention to them," said Ms. Guhl.

It's not known how high Lasius emarginatus will go. Project ManhattAnt was started by Ms. Kennett in order to help scientists track the spread of the insect in New York.

According to a professor at North Carolina State University, any ManhattAnts New Yorkers see are probably looking for water. The ant is in the ground. In all the studies we have done, it prefers to live in the woods.

ImageIn a 2006 scientific survey, no Lasius emarginatus were found in New York. It is now the most common ant in the city and has been spotted in Times Square, all along Broadway, and inside apartments, several stories up.
In a 2006 scientific survey, no Lasius emarginatus were found in New York. It is now the most common ant in the city and has been spotted in Times Square, all along Broadway, and inside apartments, several stories up.Credit...Evelyn Freja for The New York Times
In a 2006 scientific survey, no Lasius emarginatus were found in New York. It is now the most common ant in the city and has been spotted in Times Square, all along Broadway, and inside apartments, several stories up.

Ms. Kennett explained that Lasius emarginatus doesn't care about cookie crumbs. I am trying to figure this out. When ants live in urban environments, they tend to eat a lot of human foods and they can shift their diet towards more human food. Even though it is living in the most urban area, this ant doesn't seem to be consuming food.

The ManhattAnt eats other insects as well as a substance called honeydew that is made by tree pests.

The ManhattAnt is not impervious. Liquid ant baits were used by you and yours to kill the interlopers.

According to Jerry Walsh of Mayday Hardware in Prospect Heights, powerful ant baits are too potent to be used indoors. Wherever they go, they will carry that poison. You don't want that on your dishes. When you are having a mild case of stomach poisoning, you will think that you have a stomach virus.

The ManhattAnt has calmed down. They are active in April through June and less active in July.

According to Jesse, ants have always been one of the more consistent pests in New York. He didn't seem to mind when he was told that scientists had found a new species in the city that could fly.

The population of rodents has gone up a lot. There have been a lot of rats.