Ant behavior: February 2012 Archives

Hi, I have an Atta sexdens Queen and I wanted to know how can I control her fungus to not overrun the space so early? I heard that this type of leafcutter-ant grows very very fast, and if there is anyway to retard this fast process..

Giving small quantities of plants would solve this problem? Or there is another way to do it? And here I sent some pictures of my colony :)

Thank You
Best Regards,


Dear Felipe,

To answer your question, we contacted Randy Morgan, who is an expert on keeping live ant colonies and Curator of Invertebrates, Reptiles and Amphibians at the Cincinnati Zoo & Botanical Garden, and here is what he had to say:

"Congratulations for successfully collecting a young leaf cutting ant (Atta sexdens) colony! Your little colony (containing a mated queen, perhaps 50-100 workers and small fungus garden) is now about one year old and so far has been growing relatively slowly. You are correct, established colonies can grow very quickly. Your colony is just entering the stage of rapid colony growth and in several years could contain 5-8 million workers and hundreds of melon-sized fungus gardens!

Obviously keeping a fully-grown colony in captivity would be next to impossible. Even so, many universities and insect zoos keep partially-grown colonies for research and/or public educational display, and these colonies are often hardy and long-lived. However, one year old colonies are relatively fragile since fewer workers are available to help maintain an optimal nest environment (100% RH; 25-27ยบ C) for fungal growth. Environmental stress, especially even slightly lower atmospheric humidity, can lead to garden decline and eventual colony collapse. Thus, it would be ideal to grow your colony at least somewhat larger (i.e., minimally several thousand workers and two large fungus gardens) and to do so as quickly as possible. Experience has shown that it is better to keep small colonies growing rapidly and then culling excess workers and fungus from time to time, rather than limiting plant matter (the latter essentially starves the fungus and makes it less productive and poorer food for the ants). Before you drop excess fungus gardens with attendant workers into the freezer, break apart and sort through the gardens to ensure that the queen is not present!

Maintaining observation nests for Atta can provide an endless source of educational fun. To be successful long term, one should become knowledgeable about the ants' sophisticated social organization and intimate association with their fungus gardens and other resident micro-organisms. It can also be helpful to think of yourself as the "Assistant Fungus Gardener" with your primary job to do whatever is necessary to help the ants maintain a nest environment conducive to fungal growth. If the fungus thrives so will its ant colony.

Please find a document summarizing Atta biology and one husbandry system that has proven to be effective here: Leaf cutting ants-IECC 08.pdf. Of course other culturing techniques may also work as long as the needs of the fungus come first. Good luck, thanks for writing and please keep us posted on how your work with Atta is progressing.

Randy Morgan, Corrie Moreau & AskAnt Team

Dear Ant Ask,

I am 10 years old and doing a science experiment using ants. I want to find the best repellent that is planet friendly and won't kill the ants. I got some harvester ants that I have set up in a jar with sand, food and water. I got an ant farm but didn't put them in because I would not be able to get them out easily. My idea was to make 6 inch circles on construction paper. On the perimeters of each circle I would try a different kind of natural repellent such as chalk, cinnamon, catnip, mint oil. The first trial, I marked out the circle with just marker. As bait, I placed a drop of jam 3 inches outside the circle. Put 3 ants inside circle and they began to run around freely but had no interest in the jam. Tried a circle with an insecticide repellent. Ants still ran around freely, didn't care about jam. I also tried a ring of chalk, same results. Not the right bait? Bad set up? Ants to nervous? I am thinking I need to set up a habitat that they are comfortable in that I could easily manipulate. Can you help me? Any thoughts? Maybe a maze? How could I set up this experiment to show the best natural repellent without killing the ants? I really want to put them in my ant farm when I am done.

Thanks, Luke

Dear Luke,

Your idea for a science experiment sounds fun and informative!

I agree that getting your ants to feel more "comfortable" before you start the experiments is a great idea. I know you have an ant farm to move them into once you are finished with the experiments, but since you need to be able to observe them and change the repellents I would suggest moving them into a large container with a tight sealing lid (maybe like the "simple Tubberware model" found in this post). Once you have moved your ants into a temporary home with enough space for you to introduce your experimental circles of construction paper, I would wait a day or so for them to get used to the new space. Be sure to provide them with water on a moist cotton ball.

Once you start your experiments you should be sure to use a scientific "control" to insure that the ants are not deterred by the construction paper itself. To do this you will create a circle with jam, but no repellents to see if the ants are attracted to the jelly. You could also try a cotton ball soaked in sugar or honey water.

Also this post here has lots of useful information that may help with your experiments.

Best of luck and enjoy your ants after your experiments!
Corrie Moreau & the AntAsk Team

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