"Lions" Which Trap Ants

The Essays of Frances Williams ~ 1963

Published Oct 1st 2017 in , Animal Behavior, Invertebrates, Ants

Among the many fascinating creatures pictured in Howard Orians film shown in Midland last month was the ant lion. Anyone who has walked in dry, sandy places in Midland County has seen the countless tiny craters excavated by ant lions, but few have ever seen the creature that makes the structures, and fewer still had known the life history of the ant lion until seeing this film.

Curious naturalists who have excavated the craters in the sand have found a tiny, ugly, black, hairy insect only about a third of an inch long. Its body is fat and oval shaped, its head is small and has two sickle-line jaws extending forward. The ant lion exists by excavating pits in the sand and hiding in the bottom. It can only walk backwards, and it digs its little pits by backing through the sand and at the same time tossing the sand in the air by flipping its head. This process of backing into the sand until it is nearly covered and then tossing the sand out with its head continues in an ever-narrowing circle, until a neat pit has been formed with nicely sloping sides.

When the pit has been completed, the ant lion sits at the bottom and waits for his next meal to come along. He may have a long wait, but eventually an ant or other small insect will slip into the pit. The prey cannot climb out of the pit because of the loose sand and sloping walls of the trap. The ant lion emerges, seizes the hapless ant with its sickle-like Jaws. These Jaws pierce the ant and inject a poison that quickly puts an end to its struggles.

It is the larval stage of the ant lion that lives by digging craters in the sand. The insects may stay in the larval stage several years, possibly because their food supply is so haphazard and it takes a long time to acquire enough nourishment to enter the next state of the life cycle. The larva lie hidden beneath the sand during the winter, but emerge to excavate fresh craters during any warm spell.

When the time comes, ant lions build a round cocoon of sticky thread and sand grains. The creature that emerges from this cocoon is as different from the larva as a butterfly is from its larva. The adult ant lion is a gauzy-winged insect looking somewhat like a dragonfly. The pictures shown by Mr. Orians were of great Interest to those MIDNATS who are alert to all the life about them, for the adult ant lion is seldom seen. It lives a very short time, for from the time it hatches out of its granular cocoon until it dies, it does not eat. Its only function in life is to mate and lay eggs.

The way of life of the ant lion has proven to be a very successful one from the biological point of view. Ant lions have been a part of the world's life since Permian times. The order to which ant lions belong is the Neuroptera. There are some 4700 species of this order. Some relatives of the ant lion are dobsonflies and lacewings. These also have larvae that eat other insects.