How many ants are in one ant hill?
Thanks for your question!
Ants are abundant: they collectively rival with humans as dominant organisms on terrestrial ecosystems, weighing as much as all humans present on Earth; and, combined with termites, they comprise almost a third of animal biomass in tropical terrestrial habitats! The reason for such success is their social nature. More, there are around 16,000 described ants species in the world, and we think there is approximately the same number of species yet to be discovered. As their large species number indicates, ant societies exhibit a diverse array of behavior, morphology, and also nest sizes.
While Myrmoteras barbouri has around 8 individuals in their colonies, some species of nomad ants that live in the old world, A.K.A driver ants, may have nests with several million individuals. Another good example of large nests is the ones built by Atta sexdens, a leaf cutter ant living in the Neotropic, which may possess 5 to 8 million ants!
Dorylus driver ants in Kibale, Uganda. Image by Alex Wild (www.alexanderwild.com).
Among the diversity of ants we find on Earth, there are the mound-builder ants. Their nests are more than a pile of revolved soil covering an underground home; they have symmetric shape, complex interconnected systems of galleries and chambers, and are often thatched with leaves and stems fragments, or adorned with pebbles. Those types of nest indicate habitats under extreme climate. The mound reduces the loss of temperature and humidity, while it also increases the area exposed to sunlight, keeping the nest warmer than the outside environment. Their thatched or pebble sprinkled roofs are an additional heat source (think of how warm is a stone under the sunlight, or the heat produced by material in decomposition), besides preventing evaporation.
Thatched mound nest of Formica obscuripes, an ant found in North America. Image by Alex Wild (www.alexanderwild.com).
The nests of some mound-building ants, such as Formica (also known as wood ants), often last for many decades, and they can be massive, rising from the soil surface as much as 5 feet (1.5 meters).
A thatched mound nest of Formica rufa, found in Palearctic region, may have 4 million ants; while in North America, nests of the western thatching ant Formica obscuripes, house around 40,000 ants. The soil mound nests of Solenopsis invicta possess approximately 100,000 individuals.
Lateral view of Solenopsis invicta, a tramp species found in the United States. Image by April Nobile/antweb.org.
You will find interesting information on mound nests and thermoregulation here.
All the best,
Flavia Esteves & the AntAsk Team