TIL: Leafcutter Ants Farm Fungus For Food

Today, whilst discovering the fact that the tropical fire ants found in virtually all tropical climates worldwide come from Acapulco, I discovered that leafcutter ants farm fungus to eat.  Each species of leafcutter has it's own fungus that it farms, much like fig trees having just one wasp species per tree species.  Its a symbiotic relationship, the ants feed the fungus and the fungus feeds the ants. They cut up leaves and carry them on their back, pinched between the pinchers in their mouth.  Back to the nest they head to feed their fungus.

I've had some experience here in Acapulco with these buggers.  The ones I have a large, black and primarily nocturnal.  They seem to go for certain plants, picking and choosing.  When they find one they like, they strip it completely bare.  Certain Atta species are capable of completely defoliating a citrus tree in less than 24 hours, spelling disaster for farmers and gardeners.  One of my favorite bushes in our garden, the one that produces extremely fragrant flowers, got hit hard with these bastards, now it's completely bare.  Just as it started to grow back, it got hit again.  All the Bougainvilla around it are healthy and fully foliated, which makes it look terrible, honestly. 

The symbiotic relationship between ant and fungus is pretty fascinating.  They only eat fungus, which makes killing them with traditional ant poisons near impossible.  The ants are able to detect the slightest of chemical signals from the fungus, signaling them to anything toxic they may be feeding the food they are farming. If they find that the fungus is putting off certain chemical signals, they switch food sources immediately and correct the problem.

Not only can they tell when there's a problem, they secrete an actinobacteria to protect the fungus.  Many modern day anti-biotics are based off of this actinobacteria, so there's one good thing that leafcutters have contributed to the world, depending on how you look at it.  Antibiotics are the cause of a lot of issues in the world, as they've been overused in the medical field. 

I've found in my research that leafcutters are one of three fungus farming insects, the other two being termites and beetles.  Considering I didn't know any bugs farmed fungus, this also was a surprise to me.  It's interesting to hear about such small creatures farming their own food, even if they have a habit of destroying useful plants in the process.  These fungi seem to have developed a taste for the same kind of plants we have, which I find interesting.

Like I mentioned before, the fact that they only eat the fungus they farm makes it really hard to kill them.  They don't take toxins back, at least not for long so they are able to keep their food supply going no matter what.  People have taken to putting poison directly into nests, but it's not always easy to find the nests as they travel pretty far distances for food if they need to.  

I found an [article](http://www.csmonitor.com/1981/1007/100729.html) about researchers and their ongoing work in finding a natural solution.  Having noticed that there are native plants that seem to have a natural resistance to leafcutters, they're attempting to isolate the chemicals responsible for the resistance. They've succeeded in isolating 6 different chemicals and are working on testing them.  The goal is to find something with little risk to the environment.  One of these compounds is showing good promise for repelling the ants, however it is a strong antifungal and has alternative negative effects on soil health and life, making it not so worth the use.  They are still on the search for a viable chemical. 

Ants here in Mexico are no joke.  Honestly, bugs in general are crazy here but ants take the cake.  Our first night in our house, the fridge happened to have a large ant colony full of large yellow ants living inside of it.  Us moving in and turning on the fridge triggered them to evacuate, into my kitchen.  Even Rebel dog got into killing those with us, though he knows to avoid the small black ones at this point.  Next came the fire ants, after anything they could get to.  We've had leaf cutters eating our bushes, like our hibiscus bushes. Life in Mexico is never boring, even the ants are interesting!