Leafcutters on Parade

A trail of leafcutter ants carrying plant clippings.

These are leafcutters of the genus Acromyrmex, like the individual foraging on a tree in the previous post. Workers of these ants clear obstacles and debris from their foraging trails, making visible highways through grass and undergrowth.  They also seem to prefer open areas such as man-made trails to march along whenever possible.  Sometimes we would share a path with these ants down the length of an entire pasture, only to part ways with no end of the ant line in sight.

Leafcutter foraging trail.

Ant farmer – Leafcutter Ants

A leafcutter ant (genus Acromyrmex) carries her harvest down a tree trunk.

Leafcutters in my local area are fairly restricted–we have an active colony of Texas Leafcutters (Atta texana) in the nearby Lick Creek Park, but for the most part they seem to have been driven out by invasive fire ants.  I was completely charmed by all the leafcutters we saw everywhere in Argentina.  The trails of these spiky leaf-bearing ants are easy to spot–resembling tiny parades complete with banners and floats.  The busy little ants moved about their work so fast it was hard to get a good photo of them, but managed a few.

Leaf-cutting ants are found in both the genus Atta and the genus Acromyrmex.  These ants slice off pieces of plant material and carry them back to the nest.  There they are chewed into mulch which the ants use to grow a fungus which they feed on.  Leafcutters have been farming their fungal crops so long the fungal species raised by Atta and Acromyrmex nests are unique to that environment and never found outside the ant colony.