The last time I saw a sizable collection of pit-trapping antlions (Myrmeleon immaculatus, family Myrmeleontidae) in southwest Ohio was in 2017. The conical pits created by one of my favorite insects have been a rarity since then. That’s why I was thrilled to come across large numbers of pits today in Sharon Woods which is part of Great Parks of Hamilton County in the southwest part of the state.
Antlions belong to the insect order Neuroptera (neuro = nerve, ptera = wing). Adults have long, thin bodies that measure around 1" in length. They fly at night, so they are a rare find during the day.
I don't have a picture of an adult pit-trapping antlion, but I do have pictures of an adult Spotted-Winged Antlion (Dendroleon obsoletus). Online resources claim their larvae live in "dry tree holes;" I'm not sure what that means. Apparently, they are not commonly found. Regardless, the adults have a similar body plan compared toMyrmeleon immaculatusand you can clearly see the "nerve wings" which is a feature shared with all neuropterans.
Female pit-trapping antlions insert their eggs into dry, powdery soil, or sandy soil. Favored locations include loose soil near building foundations or around the base of trees.
The genus nameMyrmeleonis derived from the Latin for ant (mymex) and lion (leon). The "antlion" portion of the life cycle appears once the eggs hatch. The grayish-brown, slightly hairy larvae have armor-like plating and sport impressive out-sized, sickle-shaped mandibles, necessary equipment for a predator.
The antlions excavate their pit-fall traps by moving backward in the loose soil in a spiral pattern and using their mandibles like tiny shovels to flip away soil. Eventually, a funnel-shaped pit, measuring around 3/4 - 2" wide and 1/2" deep is created with the antlion buried at the bottom; only their wicked-looking mandibles are exposed. If you pull an antlion larva from the soil, they will immediately try to cover themselves back up with soil.
When a small arthropod blunders into the pit-fall trap, the loose dry soil particles provide no traction for escape by the hapless victim. The antlion uses its sharp-pointed mandibles to seize its trapped prey and pierce the victim's body allowing the essence-of-insect to drain into the antlion's mouth. Their dinning menu includes their namesake prey as well as any other arthropod the antlion can skewer with its mandibles.
Antlions have great edutainment value. When my kids were young, I held two antlions in a sand-based terrarium one summer; a kind of anti-ant farm. We spent hours watching them feast on ants dropped into the antlion paradise. Perhaps a timely home-schooling option?