Sand pit trap of antlion ( Kerala )

Location: Malappuram, Kerala , India

Antlions are a group of insects in the family Myrmeleontidae. The most well-known genus is Myrmeleo. There are about 2,000 species. The antlion larva is often called "doodlebug" in North America because of the odd winding, spiralling trails it leaves in the sand while looking for a good location to build its trap, as these trails look like someone has doodled in the sand. An average-sized larva digs a pit about 2 inches deep and 3 inches wide at the edge. This behavior has also been observed in a family of flies, the Vermileonidae, whose larvae dig the same sort of pit to feed on ants. Having marked out the chosen site by a circular groove, the antlion larva starts to crawl backwards, using its abdomen as a plough to shovel up the soil. By the aid of one front leg it places consecutive heaps of loosened particles upon its head, then with a smart jerk throws each little pile clear of the scene of operations. Proceeding thus it gradually works its way from the circumference towards the center. As it slowly moves round and round, the pit gradually gets deeper and deeper, until the slope angle reaches the angle of repose (that is, the steepest angle the sand can maintain, where it is on the verge of collapse from slight disturbance). When the pit is completed, the larva settles down at the bottom, buried in the soil with only the jaws projecting above the surface, often in a wide-opened position on either side of the very tip of the cone. Antlion larvae are capable of capturing and killing a variety of insects and other arthropods.