Leafcutter ant genome reveals secrets of fungus farming ways

Leafcutter ant genome reveals secrets of fungus farming ways
The leafcutter ants of the New World are signature denizens of the tropical forest and rank among the most important neotropical herbivores, harvesting as much as 17 percent of all forest leaves. The leaves are used to fuel massive underground fungus gardens, which the ants use for food. In the Feb. 10 edition of the journal Public Library of Science Genetics, a team of researchers from the labs of bacteriology Professors Cameron Currie and Garret Suen published the genome, the complete genetic blueprint, for the leafcutter Atta cephalotes. The study showed the ants' fungal farming lifestyle has led to the insect shedding nutrient acquisition genes that other ant species have retained. Photo: Wolfgang Hoffmann

Leafcutter ants, signature denizens of New World tropical forests, are unique in their ability to harvest fresh leaves to cultivate a nutrient-rich fungus as food.

Now, this mutualism -- a complicated interplay of ants, fungi and a suite of bacteria -- is coming into sharper focus as a team of University of Wisconsin-Madison researchers has published the complete genome of the leafcutter ant, Atta cephalotes.

The study, published today (Feb. 10, 2011) in the journal Public Library of Science (PLoS) Genetics, by an international team led by UW-Madison bacteriology professors Cameron Currie and Garret Suen, illustrates how lifestyle can remake an animal's over the course of .

The genome, the first for a leafcutter ant, reveals that the insect has shed genes that other use to help acquire nutrients. The leafcutter, which cannot survive without its fungus food, has apparently slimmed its genome to get rid of genes it no longer needs due to its symbiotic lifestyle.

"Presumably, the ants have lost these genes because of their dependency on the fungus," explains Wisconsin researcher Garret Suen, the lead author of the study. "They don't need these proteins kicking around any more."

Over the course of 50 million years, leafcutters and their fungus food have evolved a mutualism that enables the ants to become the insect kingdom's most successful agronomists by cultivating huge subterranean fungus gardens that are the sole source of nutrition for enormous colonies containing millions of individuals.

In the New World tropics, the only place on Earth where the estimated 45 species of leafcutters are found, the ants exert a pervasive ecological influence, harvesting as much as 17 percent of total leaf production in tropical rainforests and consuming more plants by volume than any other herbivore, including other insects and mammals. A mature colony can occupy 600 cubic meters of space.

Having the leafcutter genome in hand, say Currie and Suen, means that the evolutionary secrets of one of the most successful partnerships in nature can begin to be read in the DNA of the ant.

The project was accomplished with the support of a Roche Applied Science grant for sequencing the estimated 300 million base pairs of DNA that make up the ant's genome. The grant, which includes access to Roche sequencing technology, is now supporting the generation of genome sequences for the fungus the ant eats, as well as for a cartel of microorganisms associated with both ant and fungus.

"The opportunity to study the symbiosis is what motivated us," says Currie. "The genome allows us to understand interactions in this insect-microbial system. It improves our ability to understand the evolution of symbiosis and fungus farming in ants in a major way."

Beyond identifying the genetic signatures of the leafcutter's fungus farming ways, there are other secrets the genome will reveal as the Wisconsin group has only scratched the surface of analyzing the massive amounts of data generated for the study.

Leafcutters, for example, are known for having a diversity of body shapes and sizes to accomplish the division of labor it takes to build, defend and stock a nest containing so many individual insects. The ant's caste system, for example, includes small workers for tending to the garden and ant brood, medium-sized workers for harvesting fresh leaves, and larger soldiers; those capable of mating, have wings.

"A genome gives you a blueprint of every single gene an organism contains," Suen notes, and, ultimately, it will yield all the tightly-held secrets of the ant's mutualistic behavior and the genetic differences that underpin the ant caste system that makes one ant small and another large.


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Feb 11, 2011
he study showed the ants' fungal farming lifestyle has led to the insect shedding nutrient acquisition genes that other ant species have retained.

This article is a perfect example of how one's worldview can cloud the mind and lead to incorrect conclusions.
Firstly, the researchers have only established for a fact that the ants cannot produce/digest food like other ants because genetically they're incapable of doing so. That is the fact.
Now starts the nonsense. Secondly, when one talks about history, one understands that there is usually a detailed sequence of real events and possibly physical markers that follow one another in time. So if one talks of "evolutionary history" one needs to demonstrate the existence of such physically real events and markers. The researchers have none. Not a shred of evidence to support the claim that there was evolution in 50m years. The troubling aspect of this symbiotic relationship continues and will not go away, no matter what.

Feb 11, 2011
This symbiotic relationship is extremely annoying for evolutionists because it implies either miraculous simultaneous development or else that some outside power designed things the way it is. This article simply muddies the water even further and throws no further light on the origin of the symbiotic relationship - despite the optimism shown by the researcher.

Simply waving one's hands in the way evolutionist magicians are prone to do does not make any claim of evolution become true. It's simply wishful thinking until demonstrated supporting evidence is produced.

Feb 11, 2011
There could've been a period where both diets were consumed by the ants. And for one reason or another (perhaps it was easier) the fungus diet became more pronounced and gradually lost 'appetite' for other foods.

Feb 11, 2011
This article is a perfect example of how one's worldview can cloud the mind and lead to incorrect conclusions


Ironic, coming from a person who believes the universe is 6,000 years old, and blindly rails against the entire body of scientific evidence in favour of a fairy tale.

Now starts the nonsense


Indeed :)

So if one talks of "evolutionary history" one needs to demonstrate the existence of such physically real events and markers


But the same does not apply to the existence of your sky fairy, the flood, the universe being a mere 6,000 years old, eh Kev?

Not a shred of evidence to support the claim that there was evolution in 50m years


Done a lot of background research into this, Kev? Gone and read the study? Or just skimmed this one vague precis?

How about you produce the smallest iota of evidence supporting any of your claims? Global flood

Feb 11, 2011
Grr - lost the end of my last comment, somehow...

So, Kev, I was saying - how about you produce the smallest iota of evidence supporting any of your claims? A cataclysmic global flood - 'covering the highest mountain', occurring the last few thousand years and killing nearly every living thing on land should be pretty easy to find evidence of, so why dopn't you start with that.

No?

Thought not.


Feb 11, 2011
This symbiotic relationship is extremely annoying for evolutionists because it implies either miraculous simultaneous development or else that some outside power designed things the way it is


Except that you are utterly wrong. The evolution of symbiotic relationships is neither mysterious, unexplained, nor miraculous. It's not even unusual.

And it does not imply either 'simultaneous development' nor 'a creator'. That statement itself is a perfect demonstration of your utter lack of comprehension on this topic.

2 species each have their chances of survival increased in some small way by their interaction. Over time, that increased survival reinforces the interaction.

And that's all there is to that; there is no mystery in it. Simultaneity is neither implied nor required. 'Symbiotic' relationships are *very* common in nature.

Once again, you betray the depth of your ignorance.

Feb 11, 2011
Simply waving one's hands in the way evolutionist magicians are prone to do does not make any claim of evolution become true. It's simply wishful thinking until demonstrated supporting evidence is produced.


The supporting evidence for evolution is overwhelming. It is fact; you may as well argue against gravity.

As for 'magicians' and 'wishful thinking' - not to mention 'providing evidence'... Kev - you're a *creationist*. Surely even *you* can see the irony in your using those terms to denigrate evolutionary thought???

Feb 11, 2011

This article is a perfect example of how one's worldview can cloud the mind and lead to incorrect conclusions.
Firstly, the researchers have only established for a fact that the ants cannot produce/digest food like other ants because genetically they're incapable of doing so. That is the fact.
Now starts the nonsense. Secondly, when one talks about history, one understands that there is usually a detailed sequence of real events and possibly physical markers that follow one another in time. So if one talks of "evolutionary history" one needs to demonstrate the existence of such physically real events and markers. The researchers have none. Not a shred of evidence to support the claim that there was evolution in 50m years. The troubling aspect of this symbiotic relationship continues and will not go away, no matter what.


This comment is a perfect example of how ones religious beliefs can cloud the mind and lead to incorrect conclusions.

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