Utah Antlions

In the high Utah desert, some soils are very sandy with plenty of ants and other small crawling arthropods. The habitat is perfect for antlions. The antlion larvae make conical pits in the sand by backing in a circle and flipping sand with their large mandibles. The larva rests at the bottom under a thin layer of sand. The sides of the pit are steep and maintained at the angle of repose for the substrate. Ants, spiders or other small arthropods that wander onto the slippery slope will slide down to the bottom. If the prey does manage to halt its slide, the antlion will toss sand above and onto the head of the prey causing it to slide to the bottom. The antlion has sharp piercing mouthparts that it uses to suck the fluids from its prey. The outside of the prey, which is not consumed is flipped out of the pit with the mandibles.

The antlions may take up to 2 years to develop into adults. When the larva reaches the proper size, it will burrow further down into the sand and spin a silk case for pupation. The silk sticks to the grains of sand to create a spherical pupation chamber. The pupation process takes about a month. The adult antlions are often attracted to lights and can be found near campfires or lights. Look for them this summer.

In a previous post, I link to a video of an antlion excavation.
Antlions are relatively easy to dig out of their pits. They can be kept in a bucket of sand and fed on a diet of ants and other small arthropods. They are an interesting insect to observe and watch their development.

Antlion pits are often found in protected areas. These pits are under a rock overhang. In less sheltered areas, floods, blowing sand and large animal traffic along a trail can make life unbearable for antlions.

Left: Sand under a rock overhang is pockmarked with antlion pits.
Right: Closer view of pit.