Some ant mounds give little hint of the elaborate world hidden underneath, where nurseries, storage rooms, waste sites, and even fungus farms spread out belowground.
For some leafcutter ants in Central and South America, those subterranean "cities" can be so large that they rival the size of a tennis court.
As Discover Wildlife detailed, leafcutter ants in Central and South America dig connected tunnel networks linking nursery chambers, leaf-fed fungus plots, storage areas, and refuse zones.
Scientists have examined some of these nests by using latex or plaster to make casts of the tunnels before digging them up. Those tests revealed forms the size of camper vans and pointed to colonies of roughly 6 million ants.
However, even larger colonies may come from the invasive South American Argentine ant, Linepithema humile.
Outside its native range, colonies introduced into North America, Japan, Australia, South Africa, and Europe have merged into huge supercolonies. One European supercolony stretches 6,000 kilometers (3,728 miles) along the coasts of Portugal, Spain, France, and Italy.
Ant nests reshape soil, move plant matter, and influence the health of entire ecosystems.
Leafcutter ant nests include fungus gardens, a form of agriculture that takes place underground. That kind of large-scale activity can alter how nutrients move through forests and grasslands.
Invasive species such as the Argentine ant can push out native insects and disrupt ecological balance when they spread across multiple countries and form countless interconnected nests containing billions of ants.
Biodiversity loss makes ecosystems less resilient. When native species are displaced, the effects can extend to gardens, farms, and nearby natural areas that support pollination, soil health, and broader environmental stability.
The latex- and plaster-casting experiments give researchers a rare look at underground architecture that would otherwise remain hidden, helping scientists better understand colony size, organization, and behavior.
Monitoring invasive ants is another major tool. Because Argentine ants have spread through accidental human introduction, tracking where they appear can help researchers and officials respond before colonies become even more established.
Avoiding the movement of potentially infested soil, potted plants, and outdoor materials can reduce the risk of spreading invasive ants to new areas.
Supporting native habitats can also help. Healthier ecosystems are generally better able to withstand ecological disruption, and local invasive-species programs can give residents a direct way to protect the places where they live, work, and spend time outdoors.
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