Ant Supercolony. Image Credit: Anagoria/Wikipedia
The Argentine ant (Linepithema humile) has created one of the most remarkable biological phenomena ever recorded: a super-colony stretching around 6,000 kilometres along the Mediterranean and Atlantic coasts of Portugal, Spain, France and Italy. According to a study published in the Proceedings of the National Academy of Sciences (PNAS), these ants, which originated in South America, have formed the largest known cooperative unit in the animal kingdom.Unlike most ant species, which aggressively defend their territory against neighbouring colonies, Argentine ants in Europe display a rare social behaviour called unicoloniality. This allows billions of ants living in millions of nests to recognise one another as allies instead of rivals. The result is an enormous interconnected network that functions like a single underground city spanning thousands of kilometres, according to BBC Wildlife.
What makes the Argentine ant super-colony so large
Most people are familiar with the small mounds built by native ants, but the Argentine ant’s underground network is on an entirely different scale. Even the impressive nests of Central America’s leafcutter ants, which can grow as large as a tennis court, are tiny compared with this vast interconnected system. The super-colony stretches along Europe’s coastline, where mild Mediterranean winters and dry summers create favourable conditions for constant nest expansion. Over time, the ants have established millions of interconnected nests beneath towns, farmland and coastal landscapes. According to BBC Wildlife, billions of “happily cooperating sisters” work together across this 6,000-kilometre network, making it one of the largest known animal societies on Earth.
How does this super-colony function without conflict
The most unusual feature of the Argentine ant super-colony is the absence of fighting between ants from different nests. While colonies in their native South American range compete aggressively with one another, the European populations behave very differently.Researchers believe this cooperation is possible because the European population originated from a relatively small number of ants introduced from South America. As a result, the ants share very similar genetics and chemical signatures. Each ant carries wax-like compounds on its outer body, known as cuticular hydrocarbons, which act like an identification system. Because these chemical signals are so similar, ants from different nests recognise one another as members of the same colony instead of enemies. This allows workers to move freely between nests hundreds of kilometres apart without triggering territorial battles.
