ECO: Ant Lions – When Knew?

ECO By Peter Roos

When a quantity of perfectly round conical depressions appeared around the foundation of our 50’s beach bungalow I was ready to call an exterminator, but in an unusually lucid moment I decided first to google “conical-shaped holes in sandy yard”. I quickly learned not to call the exterminator. Ant Lions are super-beneficial bugs that control ants naturally.

Ant Lions, also known as doodle bugs in the US because they make markings like a distracted artist, are a group of insects in the Order Neuroptera – translated as “nerve wings.”  They are part of the Family Myrmeleontidae, which is of Greek origin myrmex (ant) and leon (lion).  You know you have Ant Lions when you see these upside-down cones in the dirt or sand.  These are actually traps that the (predatory) larvae set so that they can eat the ants, and other bugs or spiders, when they fall in.

The larva looks like something you would see in Star Trek The Wrath of Khan or The Mummy movies. It grows to approximately an inch long and is head bears a very impressive and sizeable pair of sickle-like jaws (mandible) that have numerous sharp, hollow projections.  In fact, their mandible is so large that it makes walking difficult and so they will typically walk backwards. They seize their prey by injecting poison that paralyzes it.  Additional digestive enzymes are injected to break down internal tissue of its prey.  It then sucks the liquefied contents of its prey’s body and then flicks it out of the pit.  The larva then repairs the pit and waits for its next victim.

Ant Lion larvae eventually pupate in the soil.  As scary as their adolescent stage appears, the adult resembles a dragonfly or damselfly except the Ant Lion folds its wings back in a tent-like fashion.  They also have longer, prominent, clubbed antennae and different type of wing venation.  Adults are rarely encountered in the wild as they are nocturnal.  They feed on nectar and pollen.

Ant Lions are often included in lists of beneficial insects, no doubt because they prey upon ants, a common pest to humans.