Fungi-farming ants: a new phylogeny

Species of ants that practice a complex form of fungi agriculture developed their knack for farming about 50 million years ago and have employed several different, successful strategies to culture their crops in the intervening millennia, according to a linkurl:study; published in __PNAS__ today. Smithsonian Institution entomologist linkurl:Ted Schultz; told __The Scientist__ that humans - who de

By | March 24, 2008

Species of ants that practice a complex form of fungi agriculture developed their knack for farming about 50 million years ago and have employed several different, successful strategies to culture their crops in the intervening millennia, according to a linkurl:study; published in __PNAS__ today. Smithsonian Institution entomologist linkurl:Ted Schultz; told __The Scientist__ that humans - who developed an linkurl:agriculture; that is still fraught with difficulties only about 10,000 years ago - could learn from the nearly 50 million year history of ant agriculture. "There has been a co-evolution [between ants and the fungi they farm] that's very much like the kind of co-evolution that has taken place between humans and our cultivars," he said. Some fungi-farming ant species have even weathered crop diseases by developing their own forms of antibiotic control. "It's possible that we could learn something from these incredibly ancient, stable states." Schultz and his colleague linkurl:Sean Brady; constructed the most complete phylogeny for 65 ant species belonging to tribe Attini, a group of ants found throughout South and Central America that sow, grow, fertilize, weed, harvest and eat gardens of fungi. "Without this phylogeny, you could only speculate about the stepwise accretion of behavioral and ecological characters that led to some complicated evolutionary endpoint," said Schultz, who specializes in the evolution of attine ants. "With the tree and with well supported nodes that tell you what those steps were, you can move beyond speculation." Schultz and Brady used standard PCR techniques to sequence four nuclear, protein-coding genes, placing ants known to practice five distinct systems of farming their fungal crops on an evolutionary tree based on the molecular data. The phylogeny concurs with speculation that fungi farming arose in ants about 50 million years ago in a warmer, more humid South America. These original ant agriculturists - whose descendants and farming methods survive today - grew a diverse array of fungal species by collecting fresh detritus from leaf-littered forest floors to fertilize their crops. Over the next 30 million years or so, four other farming strategies arose as the ants and the fungi they cultivated evolved. Schultz and Brady identified potential transitional species between these different systems of fungus farming. The most recently derived form of ant agriculture that the researchers placed on the tree is practiced by the leaf-cutter ants of tropical Central and South America. Instead of scrounging from the forest floor, leaf-cutters tailor-make their fertilizer by cutting leaves and leaf fragments, often from living plants. Leaf-cutters, said Schultz, have complex social and agricultural systems, with several different sizes of worker ants to perform the various tasks necessary to grow symbiotic, "domesticated" fungi that do not occur outside of ant gardens. Schultz and Brady found, much to their surprise, that this system evolved fairly recently by insect standards. "If I had to pick the biggest surprise," Schultz said, "it would be that the leaf-cutter ants could be less than 10 million years old." Schultz said that leaf cutters are the dominant herbivores throughout the New World tropics, with some colonies containing the biomass of a large mammalian plant-eater. "They've taken fungus growing and turned it, arguably, into one of the greatest ecological success story in all animals," he said. According to Schultz, this phylogenetic reconstruction is only the start of understanding the diversity and evolution of fungi-farming ants. More than 230 species of the ants have been described, and Schultz said that there may be more agricultural systems than the four derived forms that he and Brady addressed among them. Schultz also said that he and Brady's tree does not answer the question of how or what ant moved from not farming fungi to an agricultural lifestyle. "This tree is essentially mute about that point," he said.


Avatar of: Ruth Rosin

Ruth Rosin

Posts: 117

March 25, 2008

In my humble opinion humans should not try to learn from very primitive animals like ants, how to develop agriculture, but use the far superior ability of human "brains, to achieve that.
Avatar of: anonymous poster

anonymous poster

Posts: 1

March 26, 2008

In comment to "I think not" blog. We humans need to use our brains more and Think More not "not". Look at all the wonderful medical findings from tropical flowers and plants. Are Ants Next?
Avatar of: anonymous poster

anonymous poster

Posts: 2

March 26, 2008

Considering the potential mono-culture and agribusiness disasters . . . \n\nConsidering the disappearing honey-bee . . .\n\nConsidering global climate change . . .\n\nConsidering how successful ants have been in "farming" . . .\n\nmaybe we should adopt the humility of true science and learn from what works.

March 28, 2008

We (humans) have been learned from nature so much to say now that our superior brains have the solutions for all our problems. And example of our catastrophic but well intentioned approaches to solve global food production needs is the ?green revolution?, and addressing a large and knowledgeable scientific community, I expect no comments needed to explain what... \n\nThe scientific trends in different areas (agriculture, biomedical, etc.) are looking for answers in the way that nature through evolution found practical solution to maintain life on Earth for millions of years, the biggest ?proof, error, try again? project in history.\n\n


Posts: 3

March 28, 2008

OK - so ants developed a way of maintaining fungi for food. Took 'em a long time to do it, though, didn't it? I am pretty good at growing mushrooms, and that took only 3 years! I can also grow lettuce, radishes, beans, potatoes, you name it. Proof of primate superiority? Of course!
Avatar of: Frank Leavitt

Frank Leavitt

Posts: 9

May 21, 2009

I object to C David Bridges' post. It took many, maybe many milions of years of human agricultural experience to get to the point that Mr Bridges could plant his garden.\nAnd what is wrong with learning from other species? We learn from puppies the importance of rough play to build physical fitness. We learn from cats quiet movement. We learn aerodynamics from birds. Why not learn from ants?
Avatar of: John Burchard

John Burchard

Posts: 1

June 19, 2009

Frank Leavitt is mistaken about the antiquity of human agriculture. Homo sapiens as a species is only about a quarter million years old. The origin of agriculture is well documented at about 10,000 years ago. It developed out of gathering wild grains in a then particularly fortunate part of the world. Unlike the ants' agriculture, human agriculture has - with some limited and local exceptions - not proven truly sustainable. The present day condition of the "Fertile Crescent" area - where agriculture originated, once the world's breadbasket, now mostly unproductive desert - stands as a rather dramatic indicator of that limitation.\n\nThe crops that grow in Mr. Bridges's garden were, of course, not invented or domesticated by him, but are the product of centuries or millennia of human experience. The dramatic difference in time scales between ant and human agricultural "progress" reflects above all the human capacity for "time binding" - we can transmit complex information from generation to generation by speech and writing in a way not available to ants nor indeed except in most rudimentary form to any other animals besides ourselves.\n\nFungus farming has been invented independently more than once in the insect world. The other spectacular example is provided by various species of termites - the huge "ant hills" of the African savannas are actually built by termites and include an elaborate air circulation system which maintains suitable conditions for the fungus gardens within. Those societies are quite comparable in size and complexity - and AFAIK in biomass turnover - with those of the Attiine ants. Several other less conspicuous and AFAIK less well-studied insect groups cultivate fungi on a smaller scale and in simpler ways.\n\nI would be very interested to learn about the molecular phylogeny of those termite groups.

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