The larvae of antlions (Neuroptera: Myrmeleontidae) are ambush predators that wait patiently for prey to wander close. Those in the genus Myrmeleon have a special trick. They dig funnel-shaped pits in loose soil like sand, bury themselves at the bottom, and wait for ants and other small arthropods to fall in.
The walls of these pitfalls end up near the angle of repose. They’re just barely stable, and the slightest disturbance causes the soil to collapse. When an ant or other insect wanders past the edge it falls in and brings a cascade of debris down with it. Sensing this disturbance, the antlion larva will then flick its head and cause additional sand to rain down, helping to bring the prey to the bottom.
Once the prey item has fallen to the bottom of the pit, the antlion grasps it in its sickle-like jaws and devours it. Since catching food in this manner can be an irregular and infrequent occurrence, it can take two or three years of feeding before a larva is ready to pupate.
Once a larva has grown large enough it builds a silken cocoon and pupates beneath the soil surface. It ultimately emerges as a very different adult, a delicate winged insect that superficially resembles a dragonfly (Odonata: Anisoptera) or damselfly (Odonata: Zygoptera).