Formicarium Construction (Ytong) For Harvester Ant

12. November 2012 by Mike in Formicarium, Messor Structor  //  Tags:   //   Comments (0)

There are two parts to my formicarium, the arena (a glass tank) and the nest. I purchased all equipment from

The Arena
The arena (or foraging area) is where the harvester ants will collect seeds to stockpile in the nest. It is comprised of a glass tank with a special lid that has a gauze for airflow and to prevent them from escaping.

Around the top of the tank an anti stick coating PTFE (Polytetrafluoroethylene or more commonly known as Teflon) is applied. The PTFE comes in a small container and you brush it on as a liquid. This creates a barrier that the ants will fall off from if they climb too high.

The sand is 0-1mm washed sand which was then baked in an oven for 10 minutes. This makes the sand very dry and makes it impossible for the ants to dig into.

The pebbles are 2-8mm washed pebbles which I oven baked to make sure they were sterile. The ants subsequently used the smaller stones to seal themselves into the test tube!

The plants are plastic but look pretty real!

The cactus is a water feeder but I subsequently replaced this with a dish as the ants seemed to have trouble climbing up to it. Its VERY important to make sure there are pools of water anywhere - they drown extremely easily. Put cotton wool in any water you have - the ants will climb onto it and drink.

There are two 3/4" connectors either side to allow for future expansion. There are two common used sizes 10mm/27mm. I chose the bigger size as I figured it would stop traffic jams occurring!!

Ant Arena


The Nest
The nest is constructed out of an aerated concrete block as it has strong resistance to mold growth, maintains heat well and provides a degree of protection against the ants escaping (Harvester ants can chew through ytong though so keep an eye on them).

I measured and marked the ytong to make drilling easier. I then drilled out the ytong using a circular hole cutter (without the pilot bit) on a drill press. This gave a really smooth side wall. Next I used a normal drill and the depth limiter on my drill press to mill out the middle of the hole.


The finished nest (with heat pad temperature probe for testing). The hole to the right of the probe was where the temperature probe was finally installed - this was because it was very difficult to match the interior temperature of the nest to the reported temperature on the controller.


A thin bead of aquarium silicone (MUST use aquarium silicone as its non-toxic) was placed around the outer edge of the ytong. The glass was placed on top and weighted down over night. It is important to weigh the glass down or the ants will be able to crawl in between the ytong and the glass.


My intention is not to provide any moisture into the nest. There are many blogs around the internet that indicate this is acceptable for Harvester ants - after all if moisture was present in the nest the seeds would germinate.

End results (excuse the mess in my office!!)

The temperature probe is visible to the right, it is a cheap <£20 STC-1000 model complete with probe from eBay. Its very important to accurately place the probe and also have the ability to measure the surrounding temperature to see if the probe is accurate - I used an IR heat gun for this purpose. The species of Harvester ant I have is supposed to like temperatures of between 20-30C. The heat mat is roughly half the size of the nest so as to provide a gradient and allow the ants to move out of the heat if they want. It is important to place the heat mat above the nest and not heat from below for two reasons. It stops condensation appearing on the glass and also ytong is an excellent insulator so its much harder to heat from beneath it. The heat mat is held onto a piece of polystyrene by two elastic bands to provide further insulation at the top and to block out light to the nest.


They moved all those stones themselves on the first day to block the light in. Amazing to watch!

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