Tar Heel Ants Pogonomyrmex occidentalis Guide
Photo by Alexander Wild
This guide is meant as a supplement to the colonies we sell! The care and consideration you see here is reflective of how we are with selecting and raising our colonies we have for sale. If you are interested in purchasing one, you can do so here (Click to Order). Otherwise, please enjoy!
***Scroll to the end of this guide to see recent updates to this guide and video links to videos uploaded to Youtube on this species from Tar Heel Ants
Pogonomyrmex occidentalis News!!
(Please keep reading below at the end of this update for the main article)
The following is a brief summary of a comparison of colonies of this species when kept in diapause and non-diapause (constant growth) conditions during the winter of 2020-2021.
The time period was December of 2020 through April of 2021. 20 colonies of Pogonomyrmex occidentalis were kept in a growth condition, heated at 85-86 degrees Fahrenheit. 20 separate colonies of the same species were kept in a wine/beverage cooler concurrently for the same length of time. All of the colonies were founded from queens caught in July of 2021, and numbers ranged from 20-40 workers on average. All had been kept in the same conditions prior to the observational period, in test tubes with genesis inserts, with clean water, and fresh dandelion seeds as food.
Periodic checks of the colonies were made. For the colder colonies, the workers and queens were able to move minimally at this temperature and antennae could be seen moving when light conditions were changed during these checks. Only a few workers would walk around during this time, but the colonies were very quick to return to full functionality when left out at room temperature. This was acceptable for this period of dormancy as it was important for them not to be too cold to risk harming them.
Initial Ending Observations
At the end of the period, every colony had experienced at least one death of a worker, and some as many as 50% of the total. Obviously there was no growth during this period for these colonies, and no brood at the end of the diapause period when it ended in April of 2021.
The growth colonies, kept in a heated room for the same time period, achieved normal growth for this time period, and had significant brood piles as well.
Months later, at the end of September, the difference in the colonies of the two groups is proportionate to the number of workers lost during the period and the lack of growth. The colonies that had been kept in diapause over the winter period are now between 40-60 workers on average. The colonies that were kept in heated conditions have achieved as many as 150 workers at this time.
All queens survived through this period, and all have significant brood piles varying across the different stages of eggs, larvae (different instars), and pupae.
Observed and Expected Differences from Diapause With Pogonomyrmex occidnetalis
- Colony growth rate is slower with diapause
- Worker mortality could be higher, although a more thorough evaluation would be needed to know for certain as the colonies kept in growth conditions could have been using dead workers as food during this period and the numbers were replaced with new workers.
- Queen survival rate for colder temperatures was not seen to be lower as al queens survived the period and were producing a normal amount of brood at the end of the period as well as 6 months later at the time of this write-up.
Evaluation of Results
Diapause, being a challenging process (and stressful for early years and/or new species) for those involved in raising ant colonies, is generally not recommended for these ants in captivity. It is acceptable at the temperatures of 50-55 degrees if a winter rest period is preferred, but the loss of workers (which in my experience is not normal for most ant species during a diapause period in similar conditions) is concerning. Future years we will continue the monitoring of other colony groups of this species during similar experiments while altering temperatures primarily. Of course, we will update the findings of these here!
As a comparison, our two largest colony of Pogonomyrmex occidentalis are at this time 26 months old. Both have been kept in a constant temperature of 85-86 degrees Fahrenheit throughout their existence, and always only fed dandelion seeds, water, and the occasional slice of organic apple.
We hope some of these experiences and observations help some of you, those who are interested in or already keeping these ants in captivity, as pets!
Important Pogonomyrmex Occidentalis Characteristics As Pet Ants
- Beginner friendly
- Diet consists mostly of seeds
- Painful sting
- Bad climbers: No fluon needed
- The only federally deregulated species, at the time of writing
Maintenance cheat sheet
- Remove seeds that have sprouted (2-3 times weekly)
- Check seed piles, add more seeds as needed (weekly)
- Check water supply (2-3 times weekly)
- Offer other foods as desired (Recommended for testing interest levels) such as organic fruits, organic seeds, and insects from a reputable supplier (NEVER dead insects found around the house)
Photo by Alexander Wild
Standard practices for determining whether a queen is fertile prior to collection are:
- Ensure that collection occurs during the normal time for a mating flight (six week range maximum for most species is my personal rule). Example: Camponotus chromaiodes flew March 11th the first time I encountered the species mating flights locally. Last year it was mid-April. I would accept a queen without wings on the ground during this period of time as almost a certain sign a mating flight was occurring.
- No wings. Most queens of this species, after a successful mating, will remove wings immediately after landing. Others will even go one step further. I have seen Formica subsericea queens removing their wings in the tree branches above and dropping to the ground immediately afterwards. Do mature colonies of this species live in the area? If not, is it a windy day (if so she could have been forced off course).
- Lastly, we keep all queens under observation for any signs of irregularity. Is she tending her egg pile well? Are the eggs turning to larvae? We use high powered camera gear to observe a sample of queens every day. Only the most promising queens are available for purchase.
Caring for Pogonomyrmex occidentalis is actually proving quite simple in practice compared to other ant species I am raising. We know they need substrate (they cannot climb glass or plastic surfaces), heat is seemingly a must to push them to get started (again, this was something studied by two of the most serious people involved in the hobby, which they passed along), and, since they are harvester ants, they will need seeds.
Give them seeds and then give them more seeds. I checked out research on the genus and species. Probably the most helpful information I found was from Walter Tschinkel’s research on Pogonomyrmex badius (“Florida Harvester Ant”). In his research, he found that 70% of the seeds in a mature nest were of a size too large for workers, even majors of this species, to crush. They were waiting for seeds to crack open on their own during germination. It was mentioned that smaller seeds would be what the workers were able to crack open, so I stuck to initially working with smaller seeds but would still offer some larger seeds for colonies as they aged. One of the most interesting things to me about the species was why they needed seeds. The answer I found was that the natural environment of these ants is fairly devoid of aphids’ honeydew, which is a staple for many ant species. The seeds provide them with most of their nutrition.
Dandelion seeds are the “go-to”. These seeds are small enough for the queens to easily split them open and feed them to her first larvae. If you do not use dandelion seed then another seed of similar size and hardness (softness) will suffice.
Small amounts of apples, honey, or other liquid foods for ants would qualify. They will use their substrate to cover these liquids in many cases, so know you may lose some seeds when doing this. Apples or other organic fruits are recommended in small sizes. DO NOT LEAVE LONG ENOUGH TO MOLD. Pogonomyrmex occidentalis are seemingly not as adept at dealing with mold in captive environments. Also, know that if you allow food items to mold near their seed piles, the mold can and will spread to their seeds.
At this stage, admittedly early on in the process of learning about Pogonomyrmex occidentalis dietary needs, I would not highly recommend insects as part of their diet. They will take dead insects as food at times. According to others who have kept the genus and this particular species, a seed diet is sufficient.
Other potential diet considerations
Dietary variety with ants is important. This is true because we are simply not at a point yet where specific foods are available that have been proven to work as a single source of food for certain species or genus. In an effort to give ants all of what they need and would receive from their natural diets, offering them a variety of foods is important. For Pogonomyrmex occidentalis this is variety in the way of seeds. As earlier stated, a study from Walter Tschinkle found that in harvester ants underground chambers 70% of the seeds they found were considered too large for the ants to crush and use immediately. That would mean to me that of the seeds I currently feed to Pogonomyrmex occidentalis, 30% would be dandelion seeds and the remaining 70% would be larger seeds that they can use for food, as the seeds become soft and germinate. I have already seen a handful of boosted colonies (colonies where workers were added from another colony in the pupal stage) breaking open wheatgrass seeds and feeding the soft,white interior of the seed to the larvae. Normally these seeds are almost as large as a worker and very hard. Up to 15 times more resources are available to the colony in one large seed compared to a single smaller seed. Variety is important!
Kentucky Blue Grass
This type of grass seed is very popular as a choice but almost as common is the difficulty finding untreated versions. We have had some good results now from one type of this seed and are going to continue to try other brands with our test colonies. These seeds among others will likely be available soon from our website.
Finding Dandelion seeds naturally is fairly simple in late summer and fall. You must extract them from inside the plant when they are ready. Dandelion seeds can be found naturally, easily and with only a few minutes of effort. They can also be purchased online in small packets. The ants love them due to their small size.
This is a seed I did not find helpful initially. The seeds were larger, and some of them started germinating within a few days inside a test tube setup(with Genesis Inserts). After the seeds were split open, I did see several workers carrying around the white interior of these seeds and feeding the larvae.
It is very simple to find organic seeds, and the ants immediately took them to their nest area. They do seem a little harder than dandelion seeds to break into. These are worth a try.
As we try more and more seeds I will continue to update this section as to what I find useful. The age of the colony will play a huge factor in how readily the seeds will be used by the Pogos, and thus how good a food source they will be for your colony.
Over the years I have received numerous indications as to preferred food stuff for Pogonomyrmex occidentalis colonies. Insects are still accepted and used as food, albeit more sparingly than seeds. Try smaller insects first such as fruit flies. Ants that are not used to dealing with the decay of insects due to their natural diet consisting mainly of seeds may have more difficulty in dealing with this decaying organic material in a formicarium (captive environment). You may have to clean out parts of their habitat if dead insects are stored, and if you are using a soil-based nest (like some ant keepers do with this genus) this could be even more problematic.
These ants will need liquids added to their diet of seeds, mainly in the form of water. The amount needed will depend largely on the type of formicarium used. Formicaria that have a feature such as a cotton reservoir or constantly moist soil will have a steady supply of water available as long as they are properly hydrated by adding water. These would include cotton-plugged test tubes (tubs and tubes…) and soil-based nests. Habitats such as Tar Heel Ants Mini Hearth provide a nestmate where water is added and kept available for ants to drink via a screen-covered tube. This will provide a steady water supply. Other habitats such as a petri-dish style habitat (Tar Heel Ants Devolve Chamber is one of these) will need to be kept with either a moist cotton-ball in a cap, liquid feeder, or other watering device to ensure ants are well-hydrated and healthy. In nature these ants would get most of their water from rainwater seeping into the nest.
Housing and environment
Pogonomyrmex occidentalis cannot climb glass and plastic (and other dry, smooth surfaces). This makes it possible to have open-aired(lidless) foraging areas, if desired (though due to their painful sting, not recommended), it allows for shorter (lower) walls on foraging areas.
Photo by Alexander Wild
These ants are extremely active! Workers are in constant motion between the brood and seed piles. It is rare to see a nest where no activity is taking place, a stark difference to many other commonly kept species, particularly in the founding stage. Due to their activity levels, a slightly large or larger formicarium in general is recommended to observe their natural behaviors to their fullest.
- From a test tube setup or other small, basic founding setup all the way to the largest dirt-based formicarium, Pogonomyrmex occidentalis require as steep a humidity gradient I have encountered.
- Founding chambers should be as close to 100% humidity as possible and contain some substrate, if possible.
- Substrate requirement - If you do not provide substrate and choose a standard test tube setup, you will likely see the queen wrestling (expending a lot of valuable energy) with cotton fibers in an effort to surround her brood and herself.
- Heat is another major consideration in any setup. Some setups are more easily heated than others. Condensation and drowning are a major consideration should substrate not be provided in a habitat.
- Drinking water - these ants have slender bodies and are not capable of storing large amounts of liquids in their stomachs). It is important to provide them with plenty of drinking water to supplement their diet of seeds.
- Of the nests we have available for purchase, our Tar Heel Ants Mini Hearth formicarium is my choice for raising these founding queens. Seeds can be kept opposite the water tower or in the foraging area for storage until needed by the colony. The interior of the Mini Hearth is 90-95% humidity depending on temperature. The interior chamber is sand-coated, providing enough substrate for the queens and workers to feel comfortable. Heating a Mini Hearth is very simple with a heating cable. Place a heating cable under the opposite end of the water tower to prevent condensation. The nestmate provides a steady supply of drinking water.
Heating Pogonomyrmex occidentalis beyond an average room temperature is of paramount importance in keeping the queens’ brood healthy and growing at a proper pace! In wild conditions, where these ants are native, temperatures are often above 90 degrees Fahrenheit for much of the mating flight season and for several weeks afterwards. This would keep ground temperatures warm where the queens dig their burrows (roughly 6-12 inches underground), warmer than room temperatures for most of us. Thus, it is recommended that 12 hours daily temperature of 80-85 degrees is important to keep the brood growing at a fast enough pace for the founding colony to reach a sustainable size.
Options for Heating:
- A heat-controlled room. This is by far the best option, as it reduces the chances of condensation on the inside of the habitat and fluctuations of temperature and humidity.
Heating Cable – These can be used to heat multiple colonies and come in various lengths and wattages. This is by far the most widely used heating method for adding heat to an ant habitat. Currently we sell a version of these on our website.
- Heating Pad – These also comes in different sizes and wattages. Some are just not good at all for this type of heating. I would recommend getting the smallest and lowest powered version you can find.
- Heat Lamps – When used wisely this can be just as effective as a heat-controlled room in my experience. A heat lamp (heat bulb) can heat a smaller space, such as a corner of closet area or small room. When used in combination with a thermometer (or multiple thermometers), a range of temperature can be achieved that is necessary for these ants and others to thrive. This optimal range is different for each species.
Heating methods and tips:
There seemingly are as many types of ant habitats as there are ants, so heating specific ones will vary. There are some general principles that can be used for heating any formicarium, however:
- Heat a dry area of the habitat, as far away from the hydration source as possible. In our habitats that would be opposite side away from the water towers.
- Secure cables and cords. Be careful not to accidentally pull on these and disturb the formicarium.
- Start off heating the smallest area possible and observe what the ants do in response. Do they move the brood closer to the heat source? Do they move them further away? You can alter your heating methods accordingly. It is always best to provide your ants choices of temperature and humidity whenever possible. Doing this will add greater potential for success as an ant-keeper.
Diapause (aka, hibernation)
Diapause is the spontaneous interruption of the development of certain animals, often referred to in the community as hibernation and is marked by reduction of metabolic activity. It is typical of many insects and mites, a few crustaceans and snails, and perhaps certain other animal groups. This period of suspended development is an apparent response to the approach of adverse environmental conditions.
Diapause is the technical term for what ants experience in the winter. In warmer regions some ants do not go through diapause.
Pogos in nature dig very deep holes in the ground when colonies reach maturity. Their burrows may reach as deep as 15 feet where the constant temperature will be around 50 degrees Fahrenheit. This is the temperature I will be setting my wine cooler (where I keep my ants during diapause) at this coming winter and it is also the recommended temperature chosen for diapause conditions by most experienced ant keepers. Despite there being no formal research done to prove whether or not diapause is necessary for Pogonomyrmex occidentalis in all instances, I feel it is better to mimic their wild conditions absolutely. Other commonly kept ant species do not need colder temperatures to continue to thrive in captive diapause. I would recommend, if possible under safe conditions, four to five months of a 50-55 degree Fahrenheit temperature.
What to expect from your new colony!
- For the first few days, the queen lays eggs, and these will be difficult to spot. As she lays more and more of them, they clump together and will look like a small white glob. To prevent dehydration, I try to make sure the queen has access to drinking liquids, such as water or an apple slice. Dehydration could especially be a problem when she is found on a hot day.
- During the first couple of weeks the egg pile continues to grow larger. The queen will be more agitated and easily disturbed during this time (my own observations). Once the first eggs turn into larvae, the queen settles down noticeably.
- After the eggs turn into very small larvae, the queen can now be fed seeds. She will need to feed the larvae and herself. These queen ants are thought to be semi-claustral: that is, they require food during the nesting phase, in certain parts of their natural ranges. After keeping them for some time and in large numbers, it appears they will take food during the founding stages, and actively forage piles of seeds. Feeding them seems to help the founding process.
- “What happened to my egg pile? What started off as 20-25 eggs is now only 2-3 larvae, what happened?” These are questions I often get from hobbyists keeping queens in captivity. Simply put, many of the eggs are used as food for the growing colony. After pupae are first seen, the queen may return to laying eggs that will turn into her next workers. These new eggs will be tended primarily by the first workers, also known as nantics.
- In the first few months, a small colony should contain between 5-20 workers on average. There are a number of factors that affect the final total, including among other factors DNA, temperature, food and humidity.
These ants are not good climbers when it comes to smooth surfaces. As long as the surfaces are clean of debris and dry, Pogonomyrmex occidentalis cannot climb them. This does not translate over to other surfaces, however. These ants are very good at grabbing hold of loose objects (such as clothing and skin) with their strong mandibles and legs. Read the next section as to why this is important!
A sting from Pogonomyrmex occidentalis can cause quite a bit of pain, for up to four hours. The fact they are poor climbers makes the fact they have a painful sting less of a potential danger because they are much easier to contain than most other ants. Tips for avoiding the stings: do not stand in one place near their mounds for long periods of time. Also, when you are keeping these ants in test tube habitats, be sure to check the cotton plug before removing it. Ants can be hard to spot while trying to dig their way out through the cotton (something they do quite often when alarmed by light or vibration). Utilize the fact that they are poor climbers in planning your habitats for them. Also know that with a little dirt or condensation buildup, climbing for these ants becomes easier.
Troubleshooting with Pogonomyrmex occidentalis
“My queen has eaten her eggs.”
Sometimes this does happen: a queen has a nice pile of eggs and seemingly for no reason they disappear. This is not the same issue when a queen also has several larvae and eggs vanish. In that case, the larvae are fed eggs by the queen in an effort to feed them. It is the norm for Pogonomyrmex occidentalis queens to go from a brood of 20-25 eggs (in a neat pile she constantly carries around) to 3-5 larvae with no eggs in a few days time. Ant larvae are fed by the queen, and she uses the eggs, seeds, and any other foods she has at her disposal to do so.
Back to the vanishing eggs…
In the photo above is one example of an issue that may lead up to a queen eating her eggs. The air bubble in the test tube setup will lead to a drier interior (notice the drier cotton on the inside of the nesting area). My interpretation of this incident: the queen is reacting to a slow decrease in humidity and protecting the valuable resources she has at her disposal. She eats the eggs, keeps the nutrients in her body, and lays more eggs when conditions are good once again.
Having kept hundreds of Pogos in test tubes with Genesis inserts, substrate added in the form of coconut fiber and sand, as well as a handful of other habitats I cannot think of one time where my constant photographs, videos, or subjecting them to bright lights was suspected of having caused them to consume their brood. If the habitat is constant and good to begin with, consuming brood has never been a problem.
Tips to avoid this
- Learn to setup a test tube properly; the right amount of cotton as a plug for the water is vital and no air bubbles in the initial setup.
- Keep their substrate lightly damp (not moist). If you see water outside of the substrate pooling against the glass, it is too moist. In the event this happens, move to a new test tube and begin again.
- If possible, use a humidity control outside of the habitat. The lower the humidity where the ants are kept, the more difficult it will be to maintain proper humidity inside a habitat. NOTE: Moisture passes through the cotton plug in a test tube.
- Keep water available to drink at all times! Inside a test tube setup, water is usually available on the cotton reservoir portion (unless it is not setup properly as mentioned previously). A good habitat should have a planned method for ants to drink water. TIP: Moisten a cotton ball and stuff it in an empty water bottle cap. This allows ants to drink water from the cotton safely.
“It is taking too long for my eggs, larvae, or pupae to advance to the next stage of development. What can I do?”
For Pogonomymex occidentalis , heat is of paramount importance in the process of brood development. You need a heating cable, heat mat, or warm space to keep them in. DO NOT HEAT NEAR OR DIRECTLY ON WATER RESERVOIRS. If the brood is slowly developing or not developing at all, add heat. Email us for specific questions regarding your heat setup.
"My queen has covered herself with substrate (ie. Dug into substrate, used it to cover viewing, etc.). Is this ok?"
My recommendation would be to move this queen to a new setup, one where she does not have enough substrate to cover herself or her brood. Larger amounts of substrate is not the best method of keeping this species in my experience. Pogonomyrmex occidentalis are excellent builders and they use substrate to block light from their habitat and cover condensation forming nearby. Once the substrate dries, it will fall and potentially collapse on the queen and her brood below. We have lost a number of brood piles like this during our early research. Substrate is important for these ants; they use it for a number of tasks. Small amounts are better than large amounts, however. If you think you are giving them enough to build a home, remove some. Add a little by little over time. NOTE: In the Mini Hearth formicaria (Tar Heel Ants founding formicarium) we are raising over a dozen founding queens and small colonies. None of these have substantial loose substrate available, and all brood is developing rapidly with no signs of stress to the workers or queen from the inability to dig in their habitats. They only have enough loose sand to cover small objects.
“My queen is walking oddly, like she may be sick or injured. What should I do?”
Ants have a low recovery rate from incidents that cause such behaviors (disease, parasites, injury, lack of food or water, etc.), but it is not impossible. First make sure she is not too hot. I recommend temperature of 80-85 degrees Fahrenheit in captivity (yes, they can and will do well at warmer temperatures, but a fluctuation at higher temperatures can lead to overheating quickly). Also ensure water is available to drink. LEARNING THE HARD WAY (ALMOST): During a video session, I noticed one of my queens had lost a substantial portion of her egg pile in one formicarium. Her drinking water supply was empty, which would lead me to believe this was the cause. After I refilled her drinking water, she began producing more eggs and resumed normal growth patterns once again.
“The seeds I have given my queen are sprouting into plants.”
Should I take them out? Yes, they cannot be sustained long-term in the habitat’s ants are kept in. Removing them is the best option as they will try to consume resources your ants may need to survive.
- Seed choice remains Dandelion as the preferred seed. Kentucky Blue Grass seeds are a distant second. Crushed Pumpkin Seeds, crushed Sunflower Seeds, and even Bee Pollen have recently been seen in the mouth of larvae as we try to round out the diet consisting only of seeds.
- Mixing in a diet of insects does not seem to be a requirement to growth, however my feeling is it does aid in providing additional moisture and nutrients that are more easily consumed by the colony. Apple slices are a regular hit but I would suggest also trying other organic fruits as well to provide them easy access to moisture.
- These ants are notorious for clogging up feeders (including nestmates). I have been recommending switching out nestmates (or at minimum a thorough cleaning) every two weeks to make sure they are not clogged. This varies greatly from colony to colony. Ant colonies workers will vary in their diligence in achieving certain tasks that benefit the colony across colonies in the same species. For example, one of the largest colonies I have seen keeps a squeaky clean nestmate on one level, while the lower level nestmate (even after changing it out multiple times) stays clogged. We can only guess at why the workers did this. Perhaps is that in lower levels of a colony, those closer to the queen and brood, pose more of a threat and thus the need to block this water source is more than those further away. The point is, we must be diligent in our care and observations (making new observations) as the colonies grow in our care. Keeping ants as pets is a learning process!
Need help? Questions?
For further help regarding Pogonomymex occidentalis care please contact us firstname.lastname@example.org. We are happy to help!
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