Who Took Over Fence Line Trail?

February 2019

photo of female park rangerBy Ranger Lauren

Ant mounds on a park trailAs you walk along Fence Line Trail, the elevation changes and the trail dips into a shady and sandy area. When the ground rises back from this spot on the other side, you can see it is covered in brown mounds like large pim­ples. Upon closer in­spec­tion, you see that many little red-brown bodies are marching to and fro amongst the mounds, carry­ing giant leaf pieces over their heads like um­brel­las. You’re looking at one of nature’s earliest and most skilled farmers:  leaf cutter ants.

 Leaf cutter ants are well-known for carrying leaf pieces that are much bigger than they are. They use their scissor-like mandibles to cut huge chunks out of leaves. They drink the sap from these leaves for energy, but they don’t eat them. Instead, they use their mandibles to hold these pieces aloft and carry them into their underground colonies. For a human, that would be like hauling 600-plus pounds between our teeth!

Leaf cutter ant carrying a leafSafely inside their colonies, these farmers clean, crush and cut their leaves. They fastidiously arrange them into stacks and spread spores on them like seeds. They even compost the leaves with a little of their own poop.

How is this farming, you may ask? They use the leaf material to raise a fungus garden. The spores they spread onto the de­com­posing leaves grow into a fluffy white fungus, which to ants, is a de­li­cious and nutritious fungus! They eat certain parts of the fungus and feed it to their offspring. It is the ants’ only known source of food.

Their success as farmers has made leaf cutter ants into fungus tycoons, complete with their own underground cities and huge, half-inch soldiers to patrol them.

The colony in Lockhart State Park has been growing steadily for the last couple of years. These Texas natives can grow into large colonies of up to two million. The colonies can sometimes become as large as 50 to 80 feet across, and below ground, the nest consists of several chambers that can reach 15 to 20 feet deep.

It is astonishing what critters can be up to right beneath our feet! If you’re curious about leaf cutter ants, come see our colony along the Fence Line Trail!