Antlion

Description:

Antlions can be fairly small to very large Neuroptera (wingspan range of 2–15 cm). The antlion larvae eat small arthropods – mainly ants – while the adults of some species eat small pollen and nectar, while others are predators of small arthropods in the adult stage too. In certain species of Myrmeleontidae, such as Dendroleon pantheormis, the larva, although resembling that of Myrmeleon structurally, makes no pitfall, but seizes passing prey from any nook or crevice in which it shelters. The adult has two pairs of long, narrow, multi-veined wings in which the apical veins enclose regular oblong spaces, and a long, slender abdomen. Although they greatly resemble dragonflies or damselflies, they belong to an entirely different infraclass among the winged insects. Antlions are easily distinguished from damselflies by their prominent, apically clubbed antennae which are about as long as head and thorax combined. Also, the pattern of wing venation differs, with the very long hypostigmatic cell (behind the fusion point of Sc and R1) being several times as long as wide. They also are very feeble fliers and are normally found fluttering about in the night, in search of a mate. The adult is thus rarely seen in the wild because it is typically active only in the evening. The life cycle of the antlion begins with oviposition (egg-laying). The female antlion repeatedly taps the sand surface with the tip of her abdomen. She then inserts her abdomen into the sand and lays an egg. The antlion larva is a ferocious-appearing creature with a robust, fusiform body, a very plump abdomen, the thorax bearing three pairs of walking legs. The prothorax forms a slender mobile "neck" for the large, square, flattened head, which bears an enormous pair of sicklelike jaws with several sharp, hollow projections. The jaws are formed by the maxillae and mandibles, which in each pincer enclose a canal for injecting venom between them. Depending on species and where it lives, the larvae will either hide under leaves or pieces of wood, in cracks of rocks, or dig pits in sandy areas. Antlion larvae are unusual among the insects as they lack an anus. All the metabolic waste that is generated during the larval stage is stored and is eventually emitted as meconium near the end of its pupal stage. The pupal stage of the antlion is quiescent. The larva makes a globular cocoon of sand stuck together with fine silk spun from a slender spinneret at the posterior end of the body. These cocoons may be buried several centimeters deep in the sand. It remains there for one month, until the completion of the transformation into the sexually mature insect, which then emerges from the case, leaving the pupal integument behind, and climbs to the surface. After about 20 minutes the adult's wings are fully opened and it will fly off in search of a mate. The adult is considerably larger than the larva; they exhibit the greatest disparity in size between larva and adult of any type of holometabolous insects, by virtue of the adults having an extremely thin, flimsy exoskeleton - in other words, they have extremely low mass per unit of volume.

Habitat:

Antlions are worldwide in distribution, most common in arid and sandy habitats. A few species occur in cold-temperate places.