I am interested in setting up a formicarium. What are the best methods for setting up sustainable and easily viewable formicaria? And what North American ant species tend to lend themselves for use in an amateur formicarium? (John, Leeds, UK moving to US soon)
John, thank you very much for this question. Many people are interested in keeping ants in a formicarium (plural is formicaria, but many people just call them 'ant farms'), and they are really cool, but there are some things you need to consider.
- Types of ant farms
- Ant food and water
- Cleaning up
- Which ant species to keep?
- How to handle your ants
- Concluding remarks
Types of ant farms
Formicaria are available on the internet or from some pet shops, but you can also build one yourself. There are quite a few different types ranging from slim ant farms to simple jars which we will discuss here. You can make any type of nest more elaborate by connecting several containers with plastic tubes (clear) by cutting a whole in the container and attaching the plastic tubes using a glue gun.
The slim ant farm with dirt
The majority of ant species in temperate regions nest in the ground. When you are keeping these ants, it is a most natural habitat if you provide your ants with some dirt. In order for you to be able to see the ants, you would want an ant farm made from glass or acrylic plastic. Slim containers also make it more likely that you will see the ants, but you have to be aware that they will likely try to tunnel away from the glass. To encourage the ants to tunnel near the glass, you can cover it up with aluminum foil when you are not watching them. It is really important that the container is well sealed and your ants don't escape and find themselves a new nest somewhere in your apartment. Unless you are a skilled do-it-yourselfer, you may want to buy an ant farm from a store, because they can be quite tricky to make. You should definitely check out some websites on the net to give you some ideas. Here are some youtube videos providing step-by-step instructions for a great ant farm using old CD cases (video 1 and video 2). Also a simple way to construct a glass ant farm can be found here. Once you have the container, you want to fill it with a sand/soil mixture that stays loose and does not become hard or compact. You have to make sure that the substrate is kept moist, but not wet, in order for the ants not to dry out, but also not to drown. So before you fill your ant farm with the substrate, make sure that the substrate is moist. Slightly spray it with water and mix it. Sand and soil in equal amounts is a good mixture, but sift the dirt before you use it so it is loose. You can buy sand in aquarium shops and soil in flower supplies if you don't have anything suitable at home. There are some shops on the internet that sell ant farms filled with a blue gel. These types of ant farms are for short term keeping of ants because you cannot replace, refill or clean the blue gel, but these kinds of ant farms can be very fun and educational for children and adults alike.
This is a glass ant farm that was constructed in the lab of Robert A. Johnson (Arizona State University, USA) and instructions can be found at this website.
An ant farm from a jar filled with dirt
Another way to make an ant farm with dirt is just to use a jar. You can take an old peanut butter jar (glass or plastic), clean it out really well and remove the stickers (soak it over night and use some soap). Fill this jar about half full with dirt, again you can use a mixture of sand and soil (sift the soil in any case) in equal amounts. For ventilation, you should cut a whole in the lid and cover it with mesh. You should not use a fabric net in this ant farm model, because the ants can bite through the net and escape. Attach the mesh using a glue gun. You should NOT use Fluon® (also called "Insect-a-Slip Insect Barrier ") to coat the top 3 inches of the inside walls to prevent the ants from climbing up, because it will get very messy with the dirt and then the ants can just walk on it. See section below on feeding ants.
A simple Tupperware model
Tupperware can be quite handy when you want to make an ant farm yourself. This model is often not so fancy to look at, but it fulfills the needs of many ant species.
- Buy a Tupperware container or any plastic box with lid.
- When you keep your ants in Tupperware, they often try to walk up the walls and escape. To prevent this you can use a liquid called Fluon® (also called "Insect-a-Slip Insect Barrier ") to coat the top 3 inches of the inside glass walls. Fluon® is slippery for the ants and prevents them from walking all the way up to the lid. Use a foam brush to apply it and move the brush up and down not sideways. Let the container sit upside down for at least 2 hours allowing the Fluon® to dry and then you can turn it over, but you should wait at least 24 hours before you place your ants in the container.
- For ventilation, you have to prepare the lid of the Tupperware container. Use a cardboard cutter (careful not to cut yourself and use a cutting board underneath!!) to remove a small square from the lid (1 by 1 inch, or 2.5 by 2.5 cm² works well). Even though you have used Fluon® some ants will still reach the lid for the container. Because of this use some very fine net (wedding veil works well) and cut a piece of 2 by 2 inch (5 by 5 cm²) and cover the open square with it using a glue gun. Make sure to apply the glue tightly from the inside so that the ants don't get caught between the net and the plastic. It is unlikely that the ants will actually reach the lid, because you are using Fluon®. So the danger of the ants biting through the net is not very high. Just make sure you watch the activity of your ants at least every other day.
- Once you have the container ready, the ants need a place to actually nest in and keep their eggs, larvae and pupae (referred to as brood). You can use a test tube or make a cavity with plaster.
This picture shows a Tupperware box with Fluon® coated walls as they are used in the Moreau lab at the Field Museum. Note the hole in the lid covered by a fine net that has been attached using a glue gun. Photo by C.S. Moreau.
The Tupperware model with test tube
You can use a test tube to provide a nest to your ants. Prepare the Tupperware box as described above and then:
- Take a test tube or some other kind of tube (glass or plastic) and fill it one third with water.
- Take some cotton, form it into a ball and push it inside the tube until it is damp and prevents the water from coming out when you place to tube horizontally. The inside front part of the tube should stay dry.
- Prepare some black paper shields or tin foil to cover the tube at the dry end. This way the ants have a dark nest. Prevent the tube from rolling around by pressing it into some modeling clay at the bottom of your container.
This is a sketch of a simple Tupperware/plastic box ant farm with a test-tube as a nest for the ants (A). In part of the graph (B) you see how the test-tube is constructed. Image by D. Ballhorn.
The Tupperware model with plaster cavity
Another way of making an ant farm is using some kind of Tupperware or even a small aquarium and then making a cavity. Some additional models of this type of nest are found at this website.
- Buy some kind of plastic or glass container (a small aquarium is nice).
- Use some modeling clay and form it the way you want the cavity to look later.
- Prepare dental plaster and pour about 1-2 inch thick (2.5 - 3 cm) on the bottom. Let that dry for a few hours (about 6 hours should be sufficient).
- Then place your modeling clay on top of this bottom layer, prepare some more plaster and pour it around the modeling clay. Make sure to leave it open at the top, so you can get the modeling clay out again and access your ants later.
- Let the plaster dry for at least 24 hours, and then carefully take out the modeling clay.
- Now you have a nice cavity for your ants, but you can also decorate it making it look more natural (for example you can use natural pigments to color the dental plaster like the one shown below otherwise the plaster will be white).
- You can apply a very thin layer of glue to the plaster and take some dirt or fine sawdust and sprinkle it onto the glue layer. This will give your ant farm a more natural look than the white or grey from the plaster.
This is an image of a harvester ant colony (genus Pogonomyrmex) in a nest made with dental plaster. This nest was designed by Ray Mendez in Arizona, USA. Photo retrieved from Ant Course yearbook 2009.
Keeping twig-nesting species in twigs
Some ant species, especially in warmer climates nest in dead and hollow twigs. To keep these species in a natural habitat you can just collect the twigs and keep them in a Tupperware/plastic container or aquarium with a tight fitting, sealing lid.
- Prepare a container with Fluon® and allow for ventilation as described above.
- When you have a large number of workers in the twigs, they like to expand. You can just take some bamboo twigs (about 0.5 inch or 1 cm in diameter) and cut them into 7 inch pieces, place them in the container and the ants may move in. They will excavate the twigs themselves. This is fun to watch and gives the ants something to do.
- You can take a slightly bigger glass container/aquarium and place your bamboo twigs in there. This is great to watch when you have several active workers.
Here is an aquarium in which a colony of the twig nesting Pseudomyrmex salvini was kept. Note the twigs that the colony was collected in at the bottom and new bamboo twigs in the aquarium. Food was offered in plastic weigh boats, but any container will do. A lid was constructed from acrylic plastic, but beware because the ants started to escape because the lid became deformed due to heat lamps on top of it and Fluon® was later applied to prevent the escaping of ants. Photo by S. Kautz.
Ant food and water
In nature, ants make use of many different food sources. Some species are very specialized and for these specialists (like the leaf-cutter ants) you will need to find the food they prefer. But the majority of species lives on a mixed diet of honeydew (which is basically sugar water enriched with some amino acids) and dead insects. We will outline how to satisfy generalists.
- It is important to keep your ant farm clean and not spill the food. This prevents the ants from getting stuck, for example in honey water, and you will have fewer problems with mold.
- For the generalist ants you should provide three different "dishes", one with diluted honey, one with dead insects and one with water. You can cut plastic or aluminum foil into discs of about the size of a plastic soda bottle lid.
- Preparing the diluted honey: Mix about half a cup of honey with half a cub of water. You can add a bit of a crushed mineral and vitamin tablet, but really only a bit. Keep this refrigerated. Use an eyedropper to place little drops onto the dishes. Don't make the drops too big: the ants might drown in it!
- Preparing the dead insects. You can buy crickets from pet shops. Freeze them and then take from the freezer as needed. If you have a small ant colony, about half a cricket every other day should be sufficient. Be sure to break open the insect when you put it in the container for your ants.
- Water should also be supplied on a little ant dish and in little drops, so the ants don't drown in it or you can wet a cotton ball and put it in the nest and the ant can drink from it.
- You can slice up an apple or a carrot and offer that to your ants occasionally. They might like it.
- Place the dishes on top of the substrate in a dirt nest and on the ground in the other kinds of nests.
- Watch how much food your ants actually need and prepare the ratios accordingly.
- It should be sufficient to feed your ants every other day and clean up your ant farm by removing dead bodies or spilled food.
Moisture is very important for your ants. Since ants are so small, they can dry out very quickly and this will kill them. It is also important to avoid mold in your ant farm. So you really have to see how moist your ant farm is and then regulate it accordingly. Here are some general tips:
- When you are using a dirt nest the dirt should be moist, but not wet. Use a spray bottle to provide some moisture if it gets too low.
- When you are using a plaster nest, the plaster should be damp. Just pour a LITTLE water on it occasionally. Once you have mold, wipe it off using a paper towel. If the mold gets too bad, move your ants to a new nest. You can take out the plaster and re-use the box. Try to disturb your ants as little as possible when moving them!
- When you keep your ants in a test tube, water is provided. Just watch out that it does not get used up. But this happens only after quite some time!
- If you keep twig-nesting ants, occasionally spray them with water. This should be enough to keep their nests moist enough.
Try to remove dead bodies (both dead ants and the prey you are providing), spilled food and mold as soon as you see it! Most ants will keep their nest cavity clean and remove dead bodies from it to a trash pile they create. But, it is your job to remove the dead bodies from the container! Use forceps (tweezers) to avoid disturbing your ants as much as possible. Also try to avoid taking out the live ants and especially the brood whenever possible. This might damage them and they could die a couple of days after you touch them.
Which ant species to keep?
It is a great idea to get species that are native to the area that you live in. This prevents the establishment of invasive species (see our post on Fire ant invasions). There are some online shops that sell tropical species, but these could become a threat to our native fauna (if there are queens present) and often they have been exported illegally. Never ship ants with queens across state or country lines. So it is a good idea to drive to the woods and look for some native ants. You may want to try to get an ant queen that has mated, because workers are not sustainable. Workers do not lay eggs and they only live about 1 year, but a nest of only workers can still be quite fun to keep. You can dig up an entire nest and try to get the queen with brood and workers that way. An alternative that I would recommend is that you wait until June-August (as soon as it is the right season) and try to get a founding queen after her mating flight (see our post on How can you tell if an ant is male or female?). At this time of year, usually there are many queens that have been swarming and walk on the ground in search of a suitable site for a new nest. When you see that you should collect several queens, but you have to keep them in separate containers, because they most likely will attack each other. Once you have the queens in their container, they will lay eggs and these will develop into worker ants if she has mated. Keep in mind that native ants are a very important part of their ecosystems, and destroying a larger colony can have more of an impact on the surrounding community than you might imagine. This is another reason why it's good to start with a newly mated queen: their chances of survival, from the time they fly from their nest to their second or third year as the queen of a new colony, are very dangerous times and only a very small fraction will survive. By giving her a nice, safe formicarium to start her colony in, you might be saving her life!
All the most commonly encountered ants that live around people's houses are possible to keep in captivity, and the majority of these can be fed a generalist diet (discussed above). Here is a list with just some species native to temperate regions that can be kept in ant farms (far from complete!!!):
- Lasius species (ground nesters; native to temperate regions) Lasius niger is the most common garden ant in temperate Europe, and there are some very common species in North America, too.
- Camponotus species (often very big ants! ground nesters or nest in twigs; native to tropical and temperate regions), but these are carpenter ants so be sure to not let them escape in your home.
- Formica species (like to build mounts; native to temperate regions, rather big)
- Pogonomyrmex species (North America, harvester ants are native to arid regions, need seeds as food source and be CAREFUL!!! they have an awful sting. Check out this website for notes on Pogos in an ant farm
- Myrmecocystus species (honey pot ants, North America, arid regions)
- Messor species (harvester ants, need seeds as food source, native to temperate regions)
- Myrmica (native to temperate regions, rather small)
How to handle your ants
You should try not to touch the ants for two reasons. First, they might sting you (depending on the species you have) and second, you might harm them. When you need to pick up individual ants, because one escaped from the ant farm, use feather weight forceps (these are tweezers that are very thin and flexible and will not squish an individual ant). You can also use an aspirator, but be very careful that you don't accidentally suck in an ant. That might end badly for both on you! Here is a suggestion for an online store that cells equipment for handling ants.
Depending on the species you have and the region you have the species from, you might want to keep the ants cool in the winter (in a basement or even in the fridge). This imitates the annual cycle so the queen might have improved egg production. You should start keeping the ants in a cold room when it gets cold outside. Don't immediately place them in the fridge, but try to cool the temperature down gradually if possible. An easy way to do that is to keep them near an open window starting in late October, for example (but be careful of direct sunlight on hot days!). Then, in late November, early December, move them to the fridge. Check them weekly for moisture and always offer some food. Then, get them out the fridge again in February and try to warm them up gradually again. Even when you have ants from temperate regions they will survive if you do not overwinter them, but the egg production of the queen will be reduced after 2-3 years. So if you only have workers, you don't need to overwinter them.
There are many different ways to keep ants and we did not include all of them. There are also many kinds of ants (see our post on How many kinds of ants are there) that can be kept and hobby ant farmers as well as experts have a lot of experience on keeping ants. There are many different forums out there that discuss such experiences. A nice list of useful websites and interesting forums for people interested in ants can be found here, here, and at many other sites on the internet.
Enjoy your formicarium!
Steffi Kautz & the AntAsk Team