Immigrant Pavement Ant Tetramorium immigrans

Europe's gain is North America's problem. These tiny ants arrived as unintentional stowaways and have become one of North America's most abundant urban insects. They nest under pavement—hence the name—and thrive in the warm concrete jungles of cities and suburbs, out-competing native ants with ruthless efficiency.

What makes them successful invaders? Flexibility and aggression. Look closely and you'll see distinctive grooves on the head and thorax, plus a single pair of spines on the back. They're harmless to humans, making them fascinating examples of how some species flourish when they escape natural predators and compete unopposed in new territory.