The Antlions of Effie Yeaw

September 01, 2016

Written by Thom Parrish

Imagine the existence of a predatory creature that will grab its prey from beneath the ground, just below their feet, and drag them below the earth to devour them. Such a creature sounds like a monster from science fiction and horror, but this thing is real! It is real!! And it lives at Effie Yeaw!

Late one afternoon while walking the pond trail at the Effie Yeaw nature preserve, I glanced downward at the trail in front of me and noticed a very peculiar design drawn into the soil. It was unlike other lines I was used to seeing in the dirt, such as the lines made by turkeys dragging their wings or even by people dragging a walking stick. This line appeared as though it was slowly and carefully drawn by a finger in the dirt, meandering in an odd, crooked path for approximately 4 feet, but why on earth would someone do that? Just as I was contemplating that question I noticed something small move at the end of this very odd trail.

I leaned in for closer inspection and discovered a most bizarre looking insect-like creature, which I had never before witnessed in the preserve. It was roughly a quarter of an inch long with a round plump earth colored abdomen. At one end of its body it appeared to have a forked tail, but as I looked closer I realized it was not a tail at all, but long, sharp, serrated sickle-like jaws. The creature remained motionless as I eyed it carefully. I picked up a twig and gently prodded the creature, to which it responded by burying itself in the dirt with a quick sudden movement.

As strange and foreign as this unusual critter appeared, something about it was familiar; I felt I had seen something reminiscent on a National Geographic documentary about this creature. I took a look around the nearby surroundings to search for more clues and sure enough only a couple feet away I found the clue I needed to jog my memory. A series of small conical shaped pits dug into the soil. Now I had an idea of what this creature was; the predatory larva of the antlion!

The antlion is classified in a family of insects known as Myrmeleontidae. The name comes from a combination of the Greek words myrmex (ant) and leon (lion). Its name reflects both its voracious predatory nature and what it most often consumes as prey. The antlion has a world wide distribution in areas with warm climates. In the United States antlions are also known as “doodlebugs.” This name refers to the odd meandering trail they are known for, a trail that looks as if someone doodled in the sand with their finger.

What sets the antlion apart from other predatory insects is the unique way by which it captures its prey. The antlion will dig a conical shaped pit in loose soil approximately two inches in diameter and one inch deep. At the bottom of the pit the antlion will bury itself into the soil backwards with its jaws facing the surface. The body of the antlion is also lined with forward pointing bristles that anchor their body firmly into the sand. This pit is essentially a well constructed and thought out trap for their insect prey, primarily ants, to fall to their doom. When an ant happens to crawl over an antlion trap the steep slope and loose soil of the trap causes the ant to slide helplessly downward to the bottom where a monster waits. The conical shape of the trap guides the prey directly into the lion’s jaws.

When the ant falls within grasp the long sharp jaws of the antlion burst out from their hiding place and seize the ant, dragging it slowly underground. The hollow jaws of the antlion inject paralyzing venom into the ant’s body. Enzymes in the venom also cause the insides of the ant to break down, allowing the antlion to suck out the ant’s insides, much like a spider. Once the ant is sucked dry, the antlion will discard the shriveled carcass from the pit and wait for another victim. If an ant catches itself before it reaches the bottom of the trap and begins to crawl out the antlion will pummel the ant with a barrage of sand flung by their jaws, causing the ant to fall back down to the bottom of the pit.

Antlions choose their trap locations carefully. This is the reason for their “doodles” in the dirt. They will slowly test the soil as they meander along a path, searching for the right location where the soil feels loose enough to dig their trap.

The term “antlion” best describes the predatory larval stage of their life cycle. An antlion can remain in the larval stage for up to three years before forming a cocoon buried beneath the sand and emerging into their adult form.

The adult form of the antlion is less well known than the predatory larva. The adult antlions are most often active after dark and they are often mistaken for dragonflies or damselflies. An adult antlion will live for but a short time, approximately 3 weeks, just enough time to mate and lay eggs. Antlion larvae are most active during the summer months.

The unique and unsettling method of trapping prey has been the inspiration for some well known science fiction and horror monsters. The “Sarlaac pit” from Return of the Jedi, as well as the sand dwelling monsters in the science fiction works of Dune and Tremors have been accredited with having been inspired by antlions.

Antlions are often listed among insects that are beneficial to humans, as they reduce and control populations of other insects considered pests, such as fire ants and ticks.

Antlions are one of the most fascinating and unique predators of the animal kingdom. It is exciting to know that there is a population of antlions living in the Effie Yeaw nature preserve! Next time you see a doodle in the sand or a conical shaped pit while walking the trails, take a moment to contemplate the world beneath our feet and the role these subterranean creatures play in the incredible, interconnected ecosystem of the American Parkway.

To view short videos of antlions at work, click on the movie icons below.

This harvester ant makes a harrowing escape from an antlion trap in this incredible short video taken at Effie Yeaw. Notice the sand being thrown at the ant by the antlion!