The Ants You See On The Sidewalk Are Considered By Experts To Be Environmentally Damaging Invasive Insects

Everyone has seen anthills within pavement cracks and sidewalk crevices, and much of the time, the ants that build these hills are also visible. The group of ants that excavate soil from beneath and around paved areas are aptly known as pavement ants. People probably encounter pavement ants more often than any other group of insects. In fact, pavement ants are encountered so often that many people no longer take conscious notice of them. Although pavement ants seem well at home within the United States, they are not actually native to North America. Pavement ants were first brought to the US from Europe toward the start of the 19th century, and now they have established an invasive, and likely permanent, presence in a majority of US states as well as parts of Canada. Although pavement ants are considered to be invasive pests in the US, some research shows that these ants may benefit the environment while also harming it, albeit indirectly.

Tetramorium caespitum and Tetramorium impurum are the two pavement ant species that are most commonly encountered, and both of these species originated in Europe. Pavement ants construct their colonies in regions where vegetation is scarce, which is why they thrive within urban areas where pavement is abundant. These ants are notable for their resilience, as they are the only insects that have been documented as recolonizing areas of land that had been subject to intensive human developments, such as construction projects. A survey concerning ant diversity on New York City’s road medians found that the pavement ant species, Tetramorium caespitum, exist on 93 percent of all the city’s road medians, and they are easily the most abundant species in these areas. Not surprisingly, this species was most abundant on road medians that were relatively lacking in vegetation.

Pavement ants are considered pests to homes and vegetation, but their status as home-invading pests is questioned by some experts. However, pavement ants defend and protect other well established insect pests, such as aphids and scale insects. Both aphids and scale insects are known to dwell peacefully within pavement ant nests. By protecting these two destructive agricultural pests from predators and parasites, aphids and scale insects are able to inflict more damage to plants than they otherwise would. Pavement ants have also developed a taste for human junk food, which is why they often invade homes. It should be noted that pavement ants may also benefit the environment, as they are known for killing highly destructive ant pests, most notably red imported fire ants.

Do you avoid stepping on pavement ant nests when you encounter them on sidewalks?