Lepidoptera

The Lepidoptera, commonly known as butterflies, with over 120,000 known species, are one of the largest orders of the class of Insects. Their name derives from the Greek lepís-ídos = scale and pterón = wing, and indicates that the wings of practically all butterflies are covered with thousands of tiny scales which determine their colouration. They live in all regions where there is more or less abundant vegetation, a condition that allows the development of the caterpillars and the survival of the adults. All Lepidoptera have two pairs of wings, whose venation determines their division into Heteroneura (heteros = different, néuron = nerve) and Homoneura (homós = equal, néuron = nerve); the latter are represented by a few primitive species, often of small size, and have the veins of the forewings similar to those of the hindwings.

To the Heteroneura belong all the other known butterflies, whose forewing venation differs from that of the hindwings; this suborder is in turn divided into Heterocera and Rhopalocera. The Heterocera (hetero = different, keras = horn) include those Lepidoptera with mainly crepuscular or nocturnal habits (moths), which have antennae of various shapes and, at rest, never close their wings vertically; the Rhopalocera (rhópalon = club, keras = horn), on the other hand, are generally diurnal and, besides having club-shaped antennae, at rest hold their wings pressed together vertically, pointing upwards.

A characteristic organ typical of almost all Lepidoptera is the proboscis-shaped mouthpart (coiled proboscis) which, when extended, allows them to suck up the liquid foods on which they feed. In some moths, such as the Sphingidae, the proboscis can reach considerable lengths, at times exceeding that of the body; in other species, on the other hand, this organ is atrophied, since in the adult stage the insect lives on the food reserves accumulated during the larval period.

Lepidoptera are insects with complete metamorphosis: from the eggs develop the larvae, commonly called caterpillars, whose life may last from a minimum of one month to a maximum of three years. The duration of the pupal stage may vary from one week, a few months, or even extend to 6-7 years; this stage is often influenced by climatic conditions, and therefore undergoes considerable variations.

Adult butterflies, depending on the food they take and on their ability to undergo diapause (a period of spontaneous dormancy that halts reproductive activity in the adult), live from 2-4 weeks up to a few months. Those that take no food, on the other hand, have a very short life: they live only for the time strictly necessary to mate and lay their eggs, and this period may vary from a few days to a few hours.