Antlions (Myrmeleon sp.) are named for their larval stage. They are known to excavate funnel-shaped pits to trap ants and other insects.
Look for groups of pits, each about 2 cm across, in very fine, dry soil under overhanging rock ledges, beneath bridges, at the base of trees, or in the dirt floor of abandoned barns and sheds. When an ant or another small insect strays over the edge of one of these pits and begins to slide downward on the fine loose grains of sand, the larval antlion kicks up little fountains of earth to shower its victim and thereby accelerating its decent into the hole at the bottom of the pit where the hungry predator is waiting.
The antlion larva is also called doodlebug because of the odd winding, spiralling trails it leaves in the sand while looking for a good location to build its trap, as these trails look as if someone has doodled in the sand. There is a simple reason for the rather odd shape – the larva can only walk backwards when it is on the surface.
Here a short National Geographic video of today’s bug and how it hunts.