Results tagged “leaf-cutter ants”

Keeping live leafcutter ants (Felipe, Brazil)


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,
Felipe

2.JPG

**********
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; 25-27º 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

Keeping live leafcutter ants (Felipe, Brazil)


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,
Felipe

2.JPG

**********
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; 25-27º 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

Ant Identification (Pamela, Texas)


Dear AntAsk,

I'm in Central Texas in Limestone County and photographed some ants that were behaving like leafcutter ants. But I have never seen ants with such huge spikes on their backs! Will you please tell me exactly what kind of ant these are?

Thanks!

Pamela

AntWithSpikesOnBack.jpg

AntWithSpikesOnBack3.jpg

*****

Hey Pamela,

You're right! The ants in your photographs are indeed leafcutter ants. This particular species is Atta texana. All species of leafcutter (or fungus-farming) ants display a spiny exterior, as you point out, and in fact the number of these thoracic spines tells you the difference between the two "true" genera of leafcutters, Atta and Acromyrmex. Please see this previous post to learn more about the geographic distribution of leafcutter ants, and the second point of this post for an explanation of their spiny morphology.

Thanks for your interest!

Alexandra Westrich & the AntAsk Team

Ant Identification (Pamela, Texas)


Dear AntAsk,

I'm in Central Texas in Limestone County and photographed some ants that were behaving like leafcutter ants. But I have never seen ants with such huge spikes on their backs! Will you please tell me exactly what kind of ant these are?

Thanks!

Pamela

AntWithSpikesOnBack.jpg

AntWithSpikesOnBack3.jpg

*****

Hey Pamela,

You're right! The ants in your photographs are indeed leafcutter ants. This particular species is Atta texana. All species of leafcutter (or fungus-farming) ants display a spiny exterior, as you point out, and in fact the number of these thoracic spines tells you the difference between the two "true" genera of leafcutters, Atta and Acromyrmex. Please see this previous post to learn more about the geographic distribution of leafcutter ants, and the second point of this post for an explanation of their spiny morphology.

Thanks for your interest!

Alexandra Westrich & the AntAsk Team

What is the geographic range of leaf cutter ants (Atta spp) in the United States? Are there any known colonies of these (or other) fungus growing ants north of the Gulf States (in the Eastern US)?


Dear Don,

You may be surprised to know that leaf-cutter ants can be found in the United States! Although mostly a Neotropical group, both true leaf-cutters and the other fungus-growing attine ants can be found from South American through North America. There are ~230 described species of attine (fungus-growing) ants. In fact, attine ants are the world's first farmers and have been growing their fungal food crops for around 50 million years.

Here are the geographic distributions of the two true leaf-cutter ant genera (Atta and Acromyrmex) from the Ant Genera of the World website:

Atta_distribution.jpg

Geographic distribution of the leaf-cutter ant genus Atta. Image from Ant Genera of the World (http://www.antmacroecology.org/ant_genera; Guénard, B., M.D. Weiser, and R.R. Dunn. 2010).

Acromyrmex_distribution.jpg

Geographic distribution of the leaf-cutter ant genus Acromyrmex. Image from Ant Genera of the World (http://www.antmacroecology.org/ant_genera; Guénard, B., M.D. Weiser, and R.R. Dunn. 2010).


Recent work by Ted Schultz and Sean Brady has greatly contributed to our understanding the evolutionary history and timing of fungus-growing and leaf-cutting in the Attini ants [Ted R. Schultz & Sean G. Brady (2008) "Major evolutionary transitions in ant agriculture" PNAS 105 (14): 5435-5440.] You can read a nice review of the findings of this study on Myrmecos Blog here.

If you are interested in the geographic distributions of ants, I highly recommend checking out the Ant Genera of the World website.

Best regards,
Corrie Moreau & the AntAsk Team

This is a great question and fits well with our post below on "What is the largest ant in the world?"

Leaf-cutter ants of the genus Atta are well known for cutting and carrying bits of leaf material back to their nest. They then chew this leaf material up into a fine paste to use as the substrate to grow their food - fungus! This is where they get their other common name, fungus-growing ants. Since fungus growing ants have been cultivating fungus for ~50 millions of years, this makes them the worlds first farmers.

Atta texana worker w_leaf.jpg

Worker of Atta texana carrying leaf material back to the nest. Photo by Alex Wild (www.alexanderwild.com).


In a leaf-cutter ant colony there are many sizes of individuals from minute workers to large soldiers to the giant queen herself. The queen of leaf-cutter colonies such as Atta cephalotes can be 22 mm in length. Not quite as long as the the African driver ants mentioned in the post below, but still very large.

Atta texana queen.jpg

Queen and workers of Atta texana on fungus garden. Photo by Alex Wild (www.alexanderwild.com).


Borgmeier, T. (1959) Revision der Gattung Atta Fabricius (Hymenoptera, Formicidae). Studia Entomologica (N.S.) 2: 321-390.
Schultz, T.R. & Brady, S.G. (2008) Major evolutionary transitions in ant agriculture. PNAS 105: 5435-5440


- Corrie Moreau & the AntAsk Team

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