Antlions

Antlions are fierce predators of the garden.

Cousin to lacewings and owlflies, and often mistaken for dragonflies or damselflies, these beneficial insects fly at dusk and at night. It is their larvae, however, that do the most damage to garden pests, such as ants and termites.

Adult antlion (©entomart) Public Domain

Antlion lifecycle

Adult antlions live for only 20 to 25 days, and most antlion species do not eat anything. Those that do only eat pollen and nectar. Instead of dining, they flutter around at dusk and during the night, attracted to lights and flames, in search of a mate. After mating, the female lays her eggs in sand or plant debris. Those eggs hatch into ferocious larvae that feed until they are ready to pupate into adults. This entire cycle make take 2 to 3 years to complete.

Antlion description

Adult antlions have two pairs of clear, thin wings, and a narrow abdomen. They can be differentiated from damselflies by their long, clubbed antennae. Also, adult antlions don’t appear to fly very well.

Antlion larvae (Wikipedia) Public Domain

Antlion larvae are often called doodlebugs because of the squiggly trails they leave behind. Antlion larvae are spindle-shaped, with a plump middle and three pairs of legs. [You may have seen a variation of an antlion in the ‘Ceti eels’ from Star Trek II: Wrath of Khan]. Antlions appear to have a mobile neck (prothorax) and the head is flattened with very large, heavily ‘toothed’ jaws. Those teeth are actually sharp, hollow tubes. Within these jaws of death, antlion larvae have a canal that carries venom to immobilize their prey and enzymes to liquify them, once they are paralyzed. If that weren’t terrifying enough, antlion larvae feature forward facing bristles that help them to stand stand ground against significantly larger prey. One weird thing about antlion larvae is that they do not have an anus. Instead of releasing waste, they store it for later use as a building material for their cocoon. Any unused waste material is then released at the end of its pupal stage. [I suppose that it’s no surprise that antlion cocoons look like rabbit droppings or bird poop…]

Antlion cocoon (StephenCS) CC BY-SA 4.0

Antlion pit trap (Viren Vaz Viren) CC BY-SA 3.0

Signs of antlion habitation

How would you know if antlions are in your garden? You might see adult antlions fluttering around your porch light. Or, you might see holes in the ground. While some antlions hide in wait for their prey under leaf litter, other species of antlion larvae trap their prey in pits. They build these traps by walking backwards in circles, flipping grains of dirt and sand out of the hole with its very large jaws. Ultimately, they end up with a very steep-sided hole that can be 3/4” to 1-1/2” deep. The soil or sand around the pit is loose. At the bottom of that pit, the antlion larvae waits quietly for its next meal. As an unsuspecting insect walks by, they may fall in. When they do, it’s all over for them! As soon as prey fall in, the antlion quickly flips more soil out of the hole, making it deeper and causing grains of soil to fall on the prey, knocking it deeper into the hole. Finally, the insect is grabbed by the antlion’s large jaws and the liquefaction of its insides begins. After everything has been sucked out, the husk it thrown out of the hole and everything is tidied up for the antlion's next guest.

​Antlion folklore

There is a tale that says you can talk antlion larvae out of their holes. Simply bend down, close to the hole, and tell the antlion to tell you what you want to know. At the sound of your voice, the antlion emerges from their hole, but why? The tale says that the larvae want to hear what you have to say. What’s really happening, is the soil is disturbed by your movement and the sound vibrations of your voice, so the antlion thinks it either has lunch, or a housekeeping job to attend to.

There are over 600 antlion species worldwide. Antlion larvae are often used as fishing bait, and some people keep them as curiosity pets. How many do you have in your garden?