Parade of Leafcutter Ants

2013

Leafcutter Ants, Belize

Leafcutter ants are productive farmers with an elaborate society based on ant-fungus mutualism; i.e., a symbiotic relationship between the ant and the fungus. One day last month I had the joy of watching some especially clever ants taking a shortcut.

 

The ants get safe, underground living accommodations from the fungus, including a means to feed their ant larvae. And in turn, the ants keep the fungus fed and cleaned. Although the ants don’t actually eat from their fungal garden, they chew up the delivered leaves to decompose for the nest.

 

Many colonies contain approximately one million ants, but there can be as many as 8-10 million ants.

 

The ants bite off a piece of leaf and carry it back to the fungal garden, their underground nest. This is what we humans see as each ant carries a leaf chunk down the trail. An underground nest can grow to more than 98 feet (30 m) across, with additional chambers leading off of that.

 

Leafcutter Ant carrying leaf spear

There are many tasks in a community this large, and each individual has a specific role including the queen, several castes of workers, foragers, and soldiers.

 

Next to humans, they have the largest and most complex animal society on earth.

 

Leafcutter Ants Wikipedia

 

I’ve seen leafcutter ants in many tropical venues, and always on a forest trail or in grass. They often have a conspicuous trail, because there are so many ants moving back and forth that eventually they wear down the vegetation, as seen here.

 

Leafcutter Ant trails in grass (bottom right and leading from plant on top left)

 

Lodge Pool, Belize

 

One day Athena and I were swimming at the lodge pool, when we noticed little morsels of leaf parading across the floor tiles. There weren’t that many, maybe one ant every foot (.30 meter) or so. I don’t think other people would have even noticed them, but I am always on the lookout for leafcutters, because I think they are one of the most amazing creatures on earth.

 

The stamina! The industriousness! The tenacity of a leafcutter ant is completely inspiring. Their strength is astounding. They can carry 12-20 times their body weight.

 

After some investigation, we discovered they were taking a rainforest shortcut through the pool area. They entered at one end of the pool enclosure, walked across the pink floor tiles, and exited at the other end. This was about a 50-60 foot long (15-18 m) trail. They traveled along the floor edge, near the plantings, under the lounge chairs.

 

There were places where water was on the floor, which upset the parade. A simple small puddle threw off their scent. Here they circled around for a half minute or so, but would then stabilize, get back on track, and eventually find their way to the exit rock.

Leafcutter Ant disoriented by water spot

Each one took the exact same trail, and they all vanished at the same place. The exit rock is in the center of this photo below–there was a gap between the second and third rocks, about the size of a fist.

Rock exit, between second and third rocks

 

Ant with leaf exiting, in shadow of rock on right

As the plot thickened, we went outside the pool enclosure, thinking there would be a continued trail. But instead they were gone. They had vanished underground, reached their destination. There we stood in our dripping pool clothes, fascinated.

 

It was a very hot, humid day; all the birds were resting, all the humans were resting. But the leafcutter ants, they just kept marching.

 

Written by Jet Eliot.

Photos by Athena Alexander.

Leafcutter Ants, Costa Rica

 

Leafcutter Ants

Leafcutter Ants

Leafcutter Ants

My favorite ant in all the world.  I first saw this phenomenal creature in the Amazon, and have seen it many times in other New World tropical rainforests.  Aside from humans, leafcutters form the largest and most complex animal society on Earth (Wikipedia).  They can be found primarily in South and Central America and Mexico.

 

Upon first sight, they look like green leaves marching on the trail.  There are long lines of them–so long you can’t see where the parade starts or stops.  A closer view reveals that each piece of leaf is being carried by one ant.  The leaf is about three times bigger than the ant.

 

There is so much activity on a rainforest trail, it is easy not to notice them.  Mosquitoes are biting, the mud is slippery, unfamiliar creatures are screaming and squawking, and you’ve just been told to watch out for “monkey splatter.”  But after awhile you get your bearings, and might wonder:  why are so many ants carrying leaf bits down the trail?

 

They have just bitten a leaf morsel off a live tree and are now carrying it to their nest.  Once the ant arrives at its destination, it carries it’s green load down the center hole, and disappears from human sight. From the outside the nest is a nondescript dirt mound with a hole in the center.  But whoa, there is so much bustling activity inside this huge world.  The nests can eventually spread to 6,000 square feet with 8 million individuals in it!

 

The Nest.  It is actually a growing, living fungus.  The ants raise their young here, and need this fungus to feed their larvae.  Equally as dependent, the fungus needs the ants to nourish and tend it.  The fresh-cut leaves provide enzymes for the fungus to flourish.  In addition, the ants provide antibiotic bacteria to keep the fungus healthy.  This process is called ant-fungus mutualism.

 

Once the transporter leafcutters take the leaf pieces down into the hole, another group starts chewing.  They chew the leaves into a paste, breaking it down for the fungus to use.  As ant communities will be, other castes of leafcutters work earnestly to do their specific job.  You can read more about leafcutter ants by clicking here.

 

With all this ant life and enterprise taking place beside my two colossal feet, I figure it’s the least I can do not to step on them.

 

Photo credit:  Athena Alexander