Manhattan ants are invading New York City. Researchers have finally identified these invasive insects.

Since 2011, the invasive ant “Manhattan Ant” has been infiltrating New York City, worrying scientists, who have finally discovered the species of this larger-than-average black and red ant. Since this giant ant appeared in the heart of New York City, its population has begun to spread and, like other pests, it could cause ecological damage.

The Manhatta ant was not reported in the 2009 New York City Ant Survey. When the insect was first observed, its population was relatively small, concentrated mainly in parks. But today, it is one of the most common ants in the region, and each year its population has expanded by about 2 km, allowing the species to cross the Hudson River into New Jersey.

Although the concrete jungle might not seem like the ideal breeding ground for invasive species, several have thrived in the city, including the Asian long-horned beetle.

A research team led by Clint Penick of Auburn University says many invasive species are only discovered when they reach “pest status” and it is often difficult to identify them and try to prevent their spread.

Using DNA testing and observations of the ants, they determined that they are part of the Lasiu marginalatus species of Europe.

The researchers found the Manhattan ants where you might expect them: in trees. But they also observed them on a sixth-floor balcony and inside buildings.

“A colony of L. emarginatus “A nest was even discovered in a small planter in the middle of Times Square, far from the street trees or large ornamental plants that typically serve as nesting habitat,” the study, published in May in Biological Invasions, said. “Often, the only nonhumans visible in Times Square are humans dressed as Disney animals, and yet hidden in that flowerpot was an entire society of animal beings.”

Manhatta ants are not a supercolony, that is, large groups of ants that expand and dominate habitats, often displacing other ant species. However, they have rapidly expanded their population and may have negative impacts on other ants and trees.

They have adapted their diet to their urban environment, feeding on the honeydew of other tree pests, a sticky substance secreted by insects as they eat. This species generally does well on smooth surfaces, so city concrete is no problem. They also feed during the day and night, even when it rains, if the tree bark remains dry.

The impact of Manhattan ants on the ecosystem is not yet known, but they could be serious pests, researchers say. Many people have reported ants in their homes, and in 2022, local hardware stores reported running out of ant bait when the insects began showing up in New York City apartments.

The researchers also observed Manhattan ants dismembering other ants on the sidewalk, meaning they could be having a negative impact on local insects.

The fact that they live on the honeydew of other insects could have an impact on the health of the trees.

With 7 million trees in New York City removing 51,000 tons of carbon and 1,100 tons of air pollution per year, tree pests are a major concern, researchers say. New York City’s trees reduce residential energy costs by $17.1 million per year, and replacing the city’s trees would cost about $5.2 billion.

Because the species was detected relatively soon after its arrival in New York, researchers hope to assess its potential impact on the environment. They will continue to research the pest and are asking people to report their sightings of the species on iNaturalist, which collects photos and data about the species from the community.