Ant-lions Create Sand Traps To Catch Prey

This ant-lion is in search of an ideal trap sight. Once covered with sand at the base of a pit, it will dine on all comers small enough to grasp.

By Les Harrison
Wakulla County Extension Director

With the warm weather and ample rain, the lawns of Wakulla County are green and growing. The difficulty is finding a sunny afternoon to mow what quickly can turn into a hay crop.

Unfortunately, if there is thatch buildup, this can be the basis for fungal diseases. Sections of the lawn turn yellow, and then brown as it dies off.

The once perfect portion of horticultural bliss becomes a patchwork of sand and sod. To add insult to injury, insects quick become additional cosmetic blemishes in the barren bits of landscape. One such interloper is the ant-lion.

Ant-lions inhabit the sandy soils of north Florida and patiently await the clueless victims.  While not a member of the feline family, they have their own mythic history equally as mystic as any cat’s behavior and motivation.

The innocuous cone is often overlooked by humans, but is the pit trap of death for small insects.

The minuscule cone-shaped death traps have fascinated countless generations of children.  This ruse is said to obscure a hungry creature just below the surface that is worthy of a contemporary horror movie, complete with grasping mandibles and a pitiless gaze.

Luckily, only small ants and other insects of a similar size are susceptible to these traps. Almost everyone has seen an ant attempting to escape while suffering the sliding sand underfoot which keeps them in the tiny pit.

Ant-lions are actually found in many places round the globe, usually with dry, sandy environments.  They are member of the Myrmeleontidae insect family with about 2,000 distinct members.

What is known as the ant-lion is actually the larvae stage of a suborder of lacewings, an insect considered to be beneficial.  While this suborder or group uses sand traps to procure meals, the other suborder eats mainly aphids which are a major horticulture and agriculture pest.

This order of insects is ancient and dates back to the Permian period over 250 million years ago.  There was a mass die off of animals at end of the Permian period which saw over 70 percent of the species disappear, but the lacewings continued.

Their simple life cycle has four stages.  Eggs are laid in the sand and incubated by the warmth of the sun.

Soon the fearsome appearing ant-lion emerges and begins its search for a proper trap site.  The wondering will take the insects through a variety of micro environments.

As they travel in their search, they leave erratic tracks in the soil which appear to some as scribbling or doodling.  In this pre-pit trap phase the insect has been identified as a doodlebug.

Once ensconced in the sand trap, the ant-lion will dine on any hapless insect or spiders which exhaust themselves on the slippery walls of the cone.  As the victim slows and retreats to the bottom of the pit, the ant-lion grasp then dismembers and consumes the meal.

Once its nutritional requirements are fulfilled, the ant-lion constructs a cocoon from sand and silk.  It retires for a month long nap as it develops to a mature lacewing.

When it emerges the cycle begins again, at least until the turf regrows and its descendants move on.

For more information on Wakulla County’s ant-lions, call the UF/IFAS Wakulla County Extension Office at 850-926-3931.