Ant nests

Introduction to ant nests

The homes of ants can look very different from one another. Specific ant species have specific ant nests, and differ in the way they are constructed. Some prefer the confines of the ground while others place themselves in the treetops.

When looking at the big picture, one quickly realises that ants prefer warmth in place of cold. The tropical regions of our planet are teeming with ant species, and the closer one travels to the poles the less ants are present. This love for warmth is one of the reasons that temperate regions often have ant nests built under stones or other objects that generate heat. Ants like it when the temperatures are above 20°C, and their brood prefers it even higher to optimise their growth-curve.

Most would probably describe ant nests as the classic anthill; a mound of forest material built by the woodland ants (for example Formica rufa). A large dome out of dirt, twigs, needles, resin, leaves and small parts of charcoal. Everything needed to keep the dome impenetrable to enemies and weather. For an ant nest to work there are a few demands that should be met. Among other the following:

Protect the ants in the nest
Repel rain water
Generate heat from the sun
Conserve heat for when the sun sets

And the ants do all of this splendidly. But the large needle-infused anthill is not the most common one. It doesn’t even come close. Only 16 of the 81 Scandinavian species build these mounds, which says a lot about the diversity of other ways of generating heat and protection.

A colony of Aztec ants have built their nest in a Cordia nodosa plant. The ants and the plant live together in a state of symbiosis. Or rather, the ants live in the plant, protected from enemies, while providing the plant protection from parasites and predators. Photo: Alex Wild.

Different ant nests

Many species instead digs themselves deep below the surface of the planet. The classical mound naturally possesses the same systems of chambers beneath the earth just like a dirt-nest, but other species have all of their colony there. For example, the black garden ant of Lasius niger. It builds no mounds, but rather construct a dirt-nest in contact with a heat-absorbing object (mostly stones). Beneath the object, the larvae, pupae and queen are held during the day. The heat helps them develop. This boost to the brood and egglayers is of great importance in the competition-driven world of ants. With the heat-generating object, the ants can start their activity earlier in the spring and keep it going longer when autumn arrives. In a sense, the ants were using radiators hundreds of millions of years before mankind even existed.

A plaster ant nest by the weaver ant Pogonomyrmex badius of Florida. Photo: Shaners Becker

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References

1. Per Douwes, Johan Abenius, Björn Cederberg, Urban Wahlstedt (2012) Nationalnyckeln “Steklar: Myror-getingar. Hymenoptera: Formicidae-Vespidae” (Swedish)

2. Bert Holldobler & Edward O. Wilson (1990) “The Ants“