The insect class belongs to a branch of the arthropods including crustaceans (crabs….) myriapods (millipedes) and arachnids (scorpions, spiders….) With over a million species, insects alone represent over 75% of world fauna.
Even though the size of the most spectacular insects is hardly bigger than 20cm, insects play a fundamental role in the balance of our planet  by fulfilling a certain number of functions. In fact they are « grave-diggers » allowing the elimination and recycling  of decomposed organic matter. Others ensure the pollination of plants. Certain species are used as agricultural aids in order to fight against harmful insects. What’s more, insects form one of the first links in the alimentary chain serving as food for other insectivores. The insect world is so vast and varied  that we have chosen to exhibit only 2 groups: the most attractive and spectacular: butterflies and coleopterons.

MORPHOLOGY
Like all other arthropods, insects have a rigid skeleton; serving as a protection and a prevention against dehydration. Their body is divided into 3 parts: the head: featuring antenna, eyes, mouth-pieces.The thorax: made up of 3 segments, 3 pairs of legs, 1 or 2 pairs of wings for the flying  species. The abdomen: made up of 10’s of segments, sometimes carrying abdominal appendices (cerques, reproductive organs, sting…..)

Classification of Lepidoptera
(Lepidos=scales, ptera=wings e.g. scaled wings)

Insects of various size, called commonly butterflies, carrying generally 2 pairs of membranous wings covered in scales. The mouth-pieces are usually in the form of a proboscis, which rolls under  the head when not in use and which is used to  suck up nectar from flowers. The larvae, called caterpillars, have grinding jaws and feed on plants or animal fibre (moth caterpillars).
There are 4 stages in the life of a butterfly: egg, caterpillar, nymph (=chrysalis) and adult. The adult can live from a few days to several months. There are 170000 identified species in the world, 5000 of these can be found in France.

Rhopalocera butterflies
This group is made up of diurnal butterflies. They are usually brightly coloured, fringed antenna and their wings are vertical to their body when not in use. Their posterior wings are wide at the base and largely hidden by  their fore-wings, which allows them to synchronise their movements during flight.

Heterocera moths
This group is essentially made up of moths (nocturnal). Their colour is usually dull, but some are as brightly coloured as the Rhopalocera. Their antenna are threadlike or featherlike. They consist of one or several silk fibres attached to the base  of the posterior wing which fix into a lobe at the base of  the fore-wing. The Heterocera represent more than 80% of all "butterflies and moths" and are more primitive than the Rhopalocera.