A ancient antagony between two highly competitive ants (Linepithema humile and Solenopsis invicta) from the same river basin in South America plays out again in North America where both have been introduced. Austin, Texas, USA
Fire ants may have taken over Texas, but the invasive population is not harmonious. Here, workers have pinned down an ant from a rival colony, who defends herself with her stinger. Bastrop State Park, Texas, USA.
As neighboring Tetramorium pavement ant colonies grow into each others' territories, they test their strength in extended battles. Champaign, Illinois, USA
