Most of us were probably taught that ants live in ant hills or mounds when we were kids. Yet aside from this basic association, many don’t exactly know what these mounds are and why ants build them.
Boring as these piles of soil may seem, these mounds actually hold an interesting story behind their existence and their seemingly random construction.
Such is why in this article, we’ll discuss why ants build mounds, their ecological value and disadvantages, and if you should worry and bother to get rid of these mounds. Before all that though, let’s first understand what ant mounds are exactly.
What Are Ant Mounds?
Ant mounds or ant hills are a byproduct of the excavation done by soil-nesting ants as they build their underground nests. They’re made of fine particles of excavated soil, clay, sand, and bits of plant material, that’s taken above ground and deposited together in one location.
Depending on the size of the nest, these mounds can range from a small pile of dirt to large mounds as tall as bushes scattered all over the ground.
Why Do Ants Build Mounds?
Although ant mounds seem as if they’re mere hills of excavated soil, they actually serve an essential purpose for the nest.
These mounds act as a thermostat for the nest. During the daytime, the pile of soil absorbs heat and distributes it throughout the nest, keeping the temperature and humidity inside even, especially during night time. This allows for ants to strategically move brood around to ideal conditions that favor growth. In short, these mounds serve as moisture and temperature regulators.
Additionally, it acts as the entrance to the underground gallery of tunnels, more like the main gates of the nest which serves as a shield against vicious predators or intruders that may try to damage and invade the nest.
Ecological Value Of Ant Mounds
More than a thermostat and defense system for ants, ant mounds also provide ecological value and help with the overall balance of the ecosystem. According to research, the presence of these mounds produce a boom of diversity in plant and animal life. Since they indicate the existence of ants, the mounds attract various organisms to the habitat, which both directly and indirectly depend on ants for survival.
For instance, a mound’s regulated and warm environment is also a perfect place for the egg-laying of several insects such as grasshoppers, butterflies, and even some reptiles. Furthermore, thanks to its varying micro-climate, the presence of ant mounds, especially on grasslands, provides a conducive environment for the survival of various microorganisms, including fungi and bacteria which also provide balance to the ecosystem.
Lastly, the act of digging tunnels and creating dirt mounds is an efficient process of turning over underground soil. Like with the act of plowing, this allows organic material-rich soil to cover the topsoil encouraging the growth of various flora in the area.
Disadvantages Of Ant Mounds
Invaluable as they may be to the balance of an ecosystem, these hills also present several disadvantages, especially to humans. Since they often look like random piles of dirt, people or other animals can step on them without warning. This, in turn, makes the ants inside go crazy and overprotective of their nest, which may lead them to strike on the “attacker” by biting or stinging them.
Ant mounds are also a bane of landscape architectures and farmers. They are a particular headache on well-maintained grasses like those on golf courses, as they make the surface bumpy and hilly. And because the act of tunneling and dumping loosens the soil underground, this can also unearth crops resulting in wilting and plant death.
Should You Worry About Ant Mounds?
As mentioned, ant mounds can be quite beneficial and so for the most part don’t necessarily need to be controlled. However, they can become a nuisance and depending on the species of ants living inside the mound, even dangerous.
For instance, mounds can be rather unsightly, as they cause uneven lawns, and damage or kill grass. The ants in these mounds may also invade your house for food depending on the distance of the nest to your property.
As far as being dangerous, among the different ants that build mounds are the notorious fire ants. These ants are known for their aggressive behavior and painful stings that cause allergic reactions which may lead to anaphylaxis or symptoms such as nausea, headaches, shortness of breath, and chest pain. They’re especially dangerous to children and small animals.
All in all, despite their ecological benefits, ant mounds aren’t exactly something you’d want on your property especially if they’re housing fire ants. If such is the case, then yes, you should worry about them.
How To Get Rid Of Ant Mounds
As with any infestation, the best course of action is to contact professional help. But you can, of course, try to get rid of them yourself. To do that, you need to first locate the mound.
The quickest and usually easiest way to do so is to find and follow an ant trail back to the nest. If you can’t find a trail however, you can try searching around common nesting areas.
Ants like to make use of their environment so they typically place these mounds near food, moisture. and generally favorable conditions. Check near trees, under stones, logs, or stubs. It’s also common for these mounds to face the direction of sunlight so check those areas as well.
Once you’ve located the nest, it is then time to apply the appropriate measures. For the most part, chemical control isn’t necessary unless the mounds are inhabited by aggressive ants.
Usually, raking the mound flat and dispersing it with water is enough to at least maintain and prevent the mounds from causing damage. However, if you want to fully get rid of the mounds and the ants inside, you may use the following methods of treatment:
Simply raking the mound open and dousing it with boiling water may be enough to get rid of the nest. Doing so will flood and destroy the tunnels or galleries of the nest while also killing ants on contact.
A downside to this method however, is that there’s no guarantee that the boiling water will reach the queen, and if that’s the case then the colony can simply move to another area and rebuild.
Boiling water can also kill vegetation and possibly burn you, so be careful.
Ant baits are slow-acting insecticides made of a mixture between toxic matter and food that’s attractive to ants. They do well for out-of-reach nests as foraging ants may take them back to their nests themselves and feed the bait to the queen. When this happens, it often results in the eradication of the whole colony.
Furthermore, most commercial baits are non-toxic to humans, pets, and other wildlife, making them a safe solution to maintaining ant populations.
That said, certain ants can be selective in the baits they accept and it’s also possible for ants to neglect baits depending on food availability.
Aside from baits, other options include liquid, foam, and dust insecticides which are to be applied directly into the ant nest. When using these however, you’d have to make sure that they fully penetrate the nest or you risk the survival of the queen.
More commonly known as DE, diatomaceous earth is a chalky powder made from diatom shells that serve many functions including being an insecticide. When it comes in contact with ants, it absorbs oils and fats from their exoskeletons which upsets water balance and eventually dries up the ants and kills them.
Despite being an insecticide, DE is non-toxic to plants and other animals making it a great choice for managing ant populations. That said, they’re only suitable for dry areas as DE doesn’t work when wet. Also, DE will not provide instant results and it will take some time for it to get rid of the queen and the entire ant population.
Are Ant Hills And Ant Mounds The Same?
Yes, ant hills and mounds refer to the same build up of soil, clay, sand, and plant material which serves as the entrance of the underground nest.
How Are Ant Mounds Built?
As mentioned, ant mounds are a result of excavations done by soil-nesting ants. To create their underground tunnels and chambers, these ants make space by removing soil, debris, and other materials out of the nest. They then deposit these materials above ground and around the nest entrance, which thus form the mounds.
How Big Can Ant Mounds Get?
Ant mounds can get quite big depending on the size of the colony and their nest. For example, mature mounds of the ant species Formica exsectoides can grow up to 30 inches in height and six feet across. Other ants may also build larger mounds that grow above 8 feet in height.
In 2021, a 91 year old man discovered a 9-foot ant mound in Sweden which was believed to be the largest in the region. Researchers say that this mound houses around 300,000 ants and dates back to the 18th century.
Do All Ants Build Ant Mounds?
No, not all ants build mounds. As mounds are a product of soil excavations, they’re only built by soil-nesting ants. These ants include fire ants, harvester ants, pyramid ants, Argentine ants, and a number of ants from the Formica genus.
Summary: Why Do Ants Build Mounds?
Ants build mounds to create a thermostat that maintains the humidity and temperature of their underground nest. This allows them to keep conditions favorable for the growth and development of brood.
They also use these mounds for defense against predators and other intruders. As the entrance to the nest, these mounds serve as gates that prevent unwanted access.