Ancient Ant Supercolonies: A Glimpse Into Prehistoric Life

In 2009, researchers made a groundbreaking discovery in Europe: an enormous supercolony of Argentine ants (Linepithema humile) that spanned from northern Italy through the south of France into the northeast corner of Spain. This supercolony covered over 6,000 kilometers, making it one of the largest known insect colonies in the world. The sheer scale is staggering, with billions upon billions of ants inhabiting this vast area—many millions more than any previous estimates. To put this into perspective, this single ant colony stretches almost equivalent to the entire length of the United States.

Origin and Spread

The Argentine ant is native to South America but has spread globally due to accidental human transport. These ants often stow away in imported plants and other goods, allowing them to establish new colonies far from their original habitat. Once they arrive in a new location, they outcompete native species for resources and quickly develop their colonies.

Unique Colony Behavior

When two separate ant colonies meet, they engage in territorial battles. However, researchers found that ants from different parts of this supercolony recognized each other as allies rather than enemies. This behavior suggests all these ants belong to a single, massive colony.

Genetic Analysis

Genetic analyses have provided insights into why these ants get along so well despite being spread over such a large area. The individuals within this supercolony share a very similar genetic makeup, indicating that they are descendants of the same queen or group of queens. This common ancestry allows for memory imprinting within generations about who is part of their family and who isn’t.

Ecological Implications

This startling discovery raises significant questions about introduced populations’ ability to grow unchecked without natural predators or other ecological checks on their populations. The success and expansion of the Argentine ant supercolony highlight how invasive species can dramatically alter ecosystems by outcompeting native species and disrupting local biodiversity.

Conclusion

The discovery of the Argentine ant supercolony in Europe is not just a fascinating entomological finding but also a crucial case study in understanding the impact of invasive species on global ecosystems. As these ants spread and dominate new territories, ongoing research will be essential to manage their influence and protect native biodiversity.