Ants build their nests in a variety of ways, and can be either very simple or very complex in nature.
Ant nests are a form of shelter and home that protects ants from their enemies and the environment around them, including the weather. They also provide a suitable place for the ants to safely rear their brood and to keep their queens and themselves protected. Without their nests most ant colonies would die out very quickly; though there are a few exceptions.
Most ant nests are made in damp soil and can be several feet in depth and circumference. Other nests are made out of wood pulp chewed into a paper like substance, very similar to the way that wasps make their nests. Some ant nests are created inside the stems of plants, and one group of ant species make their nest in a ball made of leaves, which have been ‘sewn’ together by the worker ants using their larvae as silk thread producers. Some ant nests are very discreet with only one small entrance barely noticeable on the ground, whilst others, such as the southern Wood Ant, Formica rufa make large mounds of earth and pine needles, some being several feet in height, and have many entrances/exits.
The complexity of ant nests varies from species to species too. Some nests may be simple excavations of only a few tunnels and chambers, whilst others are a far more complex system of many chambers of various sizes with interconnecting tunnels. One of the best nest makers in the UK is the subterranean dwelling yellow meadow ant, Lasius flavus, whose nests are skilfully made. My Myrmica rubra colony, for example, has built a rather simple nest, made of several large vertically descending chambers, connected with a few thin corridors. These chambers seem to be in one area of the ant farm, rather than being spread out within it. Whereas my Lasius umbratus colony has made a complex nest of horizonal chambers that connect together with a simple hole in the ceiling/floor of the chamber above/below.
Generally, ants excavate their nests by biting a little chunk of soil with their jaws and carrying it outside the nest. Sometimes they will also use their front feet to assist in moving the soil as they dig; they’ll bite out the soil and drop it by their front feet, then rake the soil into a larger clump before carrying it away. Each ant tends to transport what it has dug itself, rather than any organised chain gang. Thus, sometimes ants can get in each other’s way, but a little jostling soon puts that right. Depending on how many ants there are in the colony and how large the intended nest is, it can take anywhere from a few days to several weeks to create a finished nest. On top of that nests are constantly being expanded as the colony grows in size, especially when the large flying ants start to be produced.
The environment within an ant nest is strictly controlled by the ants. They can open and close various entrances to provide more or less air circulation. The lower parts of the nest tend to be cooler and perhaps damper, and ants will often move their brood from various parts of the nest if it gets too cool, warm, wet or dry for the larvae. This is why it is vitally important that you do not dig into an ant nest when searching for ants and/or queens for your ant farm. You will ruin the carefully balanced microenvironment within. Not forgetting, of course, that by digging up an ant nest in search for, say, the queen, you could very well injure and/or kill her in the process. Then you may have sealed the doom of the entire colony. During hibernation ants will seal all the entrances and move down to the bottom of the nest so as to avoid being in areas of frozen soil during the winter frosts and snows.
Most ants will fiercely protect their nests from enemies and danger, though there are a few species that prefer to run rather than fight, picking up their brood and queens to take them to safety. Some ants can be a little lazy and rather than digging their own nest they will invade the nest of other ants, attacking them and killing them until their host ants give up and run away.
Lasius niger are my favourite ant species, and I have kept them for about 30 years. I have noticed that they tend to build many chambers connected with fairly large tunnels. They seem to prefer to make their nests on a horizontal plane rather than just going straight down. Some tunnels do, obviously, go in a downwards direction but on the whole, they tend to have various levels in their nests. They prefer to dig against a hard object such as a wall, a flat stone, or against the side of an ant farm. As the colony grows so the nest will expand both upwards and downwards. Lasius niger prefer to nest in moist soil though, of course, these can dry out over time. They tend to build fairly long tunnels some of which come close to the surface and sometimes will even break through into the open air.
Lasius flavus, the yellow meadow ant, builds quite complex soil nests, and indeed are some of the most skilled of nest makers within the British species. They are rarely seen above-ground, preferring to forage for food underground, within the soil into which they are nestin. Often, they will build mounds, especially if the colony has been well established for a number of years, and often these mounds will have various forms of vegetation growing on them, which can help mask their obvious presence. The seeds that have produced the vegetation on their mounds has probably been dropped/blown on the soil of their mounds by various natural methods, rather than the ants themselves planting them.
Lasius umbratus start their own nests/colonies when the newly mated umbratus queen infiltrates an already established nest of Lasius niger. Once the umbratus workers are produced, they build quite elaborate nests, similar to Lasius flavus.
Myrmica rubra, a red stinging ant found in gardens, meadows and forests, tend to build nests consisting of large tunnels and chambers, perhaps going down to almost half a metre. Some Myrmica species, such as Myrmica ruginodis, build smaller chambers but can be slightly nomadic in that they often move to a new nest location. My past ruginodis colony did this several time within a medium size fish tank that I kept them in.
Lasius fuliginosus, a jet- black, shiny ant with a heart shaped head, larger than Lasius niger, live in ‘carton’ nests. They create these nests in old tree stumps, where the wood has died and rotted to the extent that it is easy for the ants to bite and chew the wood. They will mix this chewed wood with honeydew, making a substance like Papier-mâché. They then use the pulp to create the physical nest itself. Similar to the way many wasps build their nests and to be a fairly tough material, tougher than the paper nests created by wasps. They will still dig tunnels down into the soil beneath the tree stump and will move down into these deeper soil tunnels during the winter hibernation months.
Formica fusca is another dark ant found in the UK, which builds its nests in soil. However, rather than having a lot of horizontal tunnels and chambers like Lasius niger do, they tend to build deeper tunnels connected by a series of vertical shafts, with one small entrance on the surface. I had a colony of these once and they did just that, building their nest in the centre of the fish tank I kept them in, underneath a piece of dead wood.
Formica rufa, the red wood ant found in pine forests of southern England, builds large thatched mounds which, like Lasius fuliginosus, tend to start centred around old tree stumps. The wood ants bring soil and various plant detritus, commonly pine needles, to build up over the tree stump until it is eventually completely covered. The nest extends throughout the mound, into the stump, and into the ground. These mounds can be as high as one metre and have a circumference of several metres. They tend to be situated on the edge of pine forests, particularly where a pathway meets the forest edge; this is because the ants like to have the sun shine on the mound as much as possible in order to keep it warm. It is interesting to note that Formica rufa build their mounds with the south facing slope being at a gentler incline than the other sides. They do this so that the south facing slope, which is the side facing the sun most of the day, has a larger surface area and therefore captures more of the sun’s warmth. This acts as a kind of central heating method, as when the colder nights come in, the heated surface of the mound slowly releases the heat it has stored during the day, which radiates into the nest. Also, heat is generated by the decomposing plant material on, and within the mound, which, again, radiates into the nest. This is actually very important during the winter, as it helps prevent the ants from freezing in cold conditions such as frost, when hibernating. The mounds have many entrances which are opened and closed in order to maintain a specific inside microenvironment. Within, which is extremely important for the development of the brood.
Temnothorax nylanderi are a very small yellow-brown species of ant that often builds its nests inside rotting, hollowed out acorns. These tend to have small colonies of only a few hundred ants.
The nests of some species of ant in the tropics of the world can be even more impressive.
Some species of Leafcutter ant, for example, can builds chambers so large than a man could stand up in one!
Weaver ants, as their name suggest, “weave” their nests. They find a suitable tree or large plant and pull leaves toward each other so that their leading edges touch. The ants will often form several chains of 2 or 3 ants that are used to pull the edges of the leaves together to achieve this. Other ants will then pick up their larvae and touch the mouth of the larvae to one of the leaf edges. The larvae then produce a silk like thread which is sticky, much like a spider does when making a web, and, incredibly, the ants will use the larvae as sewing needles and stitch the leaves together. This eventually creates a ball of leaves in which the ants live.
Some army ant species do not have nests in the traditional sense, but rather they are nomadic. They do nests in one area for a short period of time, whilst the brood develops into adult ants. Other than that, they are constantly on the move. When they do stop as just mentioned, they create a bivouac, a nest structure made of their own living bodies. Huge numbers of ants link themselves together, to form the walls of the living nest, with the queen and brood protected inside. The remainder of the ants will go out in large numbers to forage. Once it is time to move on, the living nest breaks up and all the ants then march off in search for another area to nest in. Why do they not just stay in one place? Some of these army ant colonies can have up to 20 million ants, and so they can very quickly wipe out prey fauna, especially other insects. By moving about they not only find more food, but it allows the area that have moved out of to recover its fauna.
This is a picture of my captive Myrmica rubra colony. As you can see they have built a series of large design chambers, link by a tunnel. The thin horizontal tunnel you see disappearing to the right is a dead end.
From my experience with other rubra colonies that I have had, this seems to be their usual nest build.
This is a photograph of a seemingly abandoned part of my Lasius umbratus colony.
Note the many horizontal chambers, which are linked not so much by tunnels, but rather by entrance/exit holes in the ceiling/floor of each chamber.
This picture was kindly provided to me by Timothy Goodman. He was working in the pump room of a swimming pool in, I think, a school. He discovered this ant nest among the pipework.
This is a cartoon nest of Lasius fuliginosus. Note the similarity of this method of nest building to that of a wasp.