“Doodle bug “is the larva of Ant lion insect. It constructs pitfall traps in sand. While locating suitable place for the trap, it leaves spiraling trails along its path, hence its name.
The adult ant lion insects resemble Dragon flies or Damsel flies in body shape and wings, though the two belong to different orders of insects. The ant lion can be distinguished by its clubbed antenna and nocturnal life (i.e., active during nights).
Ant lions of south western United States belong to the genera, Myrmeleon and Brachynemurus. They have two pairs of long narrow wings. The wing span ranges from 2 to 6 inches. The wings are rich with complicated patterns of veins. Abdomen is long and slender. The adult insects are attracted to lights and campfires and are abundant during summer and late fall. They are feeble fliers and flutter all through nights in search of a mate.
The female antlion inserts its abdomen into sand and lays a single egg, which hatches into a larva that looks fearsome. The larva or doodle bug has a robust spindle shaped body. Its head is small and bears a pair of large sickle shaped jaws with sharp teeth. With these jaws the larva pierces its prey and injects venom and digestive juices. The body contents of the prey are converted into a juice, which the larva sucks out.
To trap its prey, the antlion larva constructs a pitfall trap. It finds a soft and dry sand area beneath trees such as cottonweed, willow or overhanging rocks. The larva digs a conical pit about 1 to 2 inches wide at its moth and about the same length, deep.
The antlion larva stays at the bottom of the pit with its jaws wide open. Crawling insects fall into the pit. The loose sand of the walls of the pit makes the escape of prey, difficult. Meanwhile, the larva catches the prey with its powerful jaws.
When fully grown, the larva constructs a spherical cocoon made of silk and sand grains. Its silk secretion comes from its anal region .The cocoon resembles rabbit’s droppings and lies buried under sand. The manner in which the larva builds its sand cocoon without sand grains getting inside the cocoon is considered a great feat.
The larva becomes pupa and undergoes development inside the cocoon. Pupation lasts several weeks, sometimes months. After metamorphosis, the adult insect breaks the wall of the sand cocoon, crawls up to the surface and flies away.