Here’s one that has shown up on almost all of the Track and Sign Evals that I’ve taken, the Antlion. This small insect creates these pit traps to capture ants and other small insects. These are constructed in loose sand and dirt usually in protected areas, under bridges, rock overhangs, or other natural or manmade structures. These are under a car port so the dirt stays dry and loose. I’ve watched small insects fall into one of these traps, the steep angle and the loose sand/dirt makes escape difficult. The antlion hiding at the bottom of the pit pops out and grabs it’s prey.
When there’s one antlion pit trap, there tends to be many more. And one antlion will work several pits. The antlion larvae made the line trails seen in the top photo below the penny. Many other insects make similar trails in the dirt. So one way to be sure it’s from antlions is that they usually run from one pit to another, sometimes by very indirect routes.
In the above photo, a view of a larger area with numerous antlion pits and several trails. Sometimes if you stop to watch them for a while, you might see one of the pits getting made or cleaned. The antlion moves in a circle at the bottom of the pit kicking out sand/dirt/debris. It can be quite fascinating to watch.