If I were to mention an ant-fungus mutualism- that is, an ecological partnership between an ant and a fungus that benefits both- most biologically literate people might think of the famed leafcutter ants and the edible mycelia they cultivate. But that is just one example.
Several other fungi have entered into productive relationships with ants, assisting especially in ant architecture. Consider:
Lasius umbratus walking in the galleries of an underground carton nest (Illinois)
A larger view of the same nest. The intricate galleries are made from fungal mycelia growing through a matrix of ant-chewed wood pulp.
Here in North America, ants in the common subterranean species Lasius umbratus build extensive nests of chewed wood pulp. But wood pulp itself is flimsy, so the ants have recruited a fungus that grows through nest walls, strengthening the structures much like we humans use steel rebar to reinforce our concrete construction. The product is carton- a stiff, lightweight substance. Remarkably, no one has ever studied this relationship on our continent. All the research on Lasius and their fungi has focused on European populations.
Tropical ants also make carton with the help of fungi. One recent study by Mayer & Volglmayr (2009) cultured several species from the arboreal runway galleries of Azteca brevis in Costa Rica. Ant-plant ants in Allomerus and Aphomyrmex employ structural fungal symbionts as well, using them to bind plant trichomes into carton.
This Azteca carton shed in Guatemala houses mealybugs on the underside of a tree branch.
Where am I going with this post?
It’s that the more that we look in detail at life on earth, the more intricately interwoven we find it to be. There are microbes living on ant cuticles and bacteria digesting ant food. The reason we know about the fungal symbioses is that someone went looking for them. But as most ant species haven’t been screened for symbionts, the reality is we know hardly anything about the diversity that’s out there. Just enough to know that many lifetimes’ of study await those who are curious about it.
Myrmecos Blog 
The fungal architecture reminds me of a building style called “flying concrete.” You make shapes with wire mesh and rebar and then fill it in with concrete.
An example: http://www.mortarsprayer.com/wp-content/gallery/flyingconcrete/Organic-sculpted-home.jpg
For further reading, here’s a state of the art paper on the evolution of Lasius and its fungiculture:
http://www.biomedcentral.com/1471-2148/8/237
This paper demonstrates a nice blend of morphological, genetic and behavioral analysis in determining phylogeny.
An Aphaenogaster species I once caught from my yard went on to build a structure much like that in their terrarium.
I know this isn’t really related to these pictures, but I have a question. I might be taking a trip soon to Australia, and was hoping to collect some ants. However, I can’t seem to find a clear explanation as to if and how I can bring ants (in alcohol or otherwise) home with me to the USA. I thought that you might know or know someone who would know. Thank you.
There are several layers of complications to bringing ants out of Australia. First is that Australia regulates insect collecting and exportation as wildlife, so you’ll need to get the appropriate forms filled out both for collection permission and export permission. This is easier if you have an institutional affiliation, but not impossible. Contact the staff at a museum or university near where you’re going and they’ll point you in the right direction.
The second layer has to do with airline safety regulations on flying with flammables such as ethanol. I’d drain the liquid out of vials prior to flying. You can refill once you get back to the U.S. Alternately, you can also mail them to yourself.
The third layer is getting specimens into the U.S. If your ants are preserved specimens you should not have a problem if the species you collected aren’t CITES-listed (and they won’t be, for what you’re liable to encounter).
I would not try to bring live ants back. The permit process for legal importation is basically impossible unless you are a professional scientist with a formal research project and several months to push the permits through.
All this said, though, Australia has some amazing ants.
Thanks for the tips. I’ll get in touch with a museum over there and see if they even issue permits to people under 18. (Do you by chance know?) If worst comes to worst, I always have my camera!
Your blog is my absolute favorite resource!
Thank you,
Tucker
No worries. One nice thing about contacting local scientists- permits or no- is they are often happy to provide tips about good places to collect and interesting species to look out for.
Is the Lasius umbratus picture from a lab colony, or was this dug up?
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This reminds me of a TED talk by Magnus Larsson about turning dunes into architecture….check out these human size carton nests!!!