An insect is an invertebrate animal, whose body is protected and maintained by an exoskeleton, is made up of three segments and which has three pairs of legs.
Insects are the most common type of animal on our nature trail, where you can find: Lepidopterans (butterflies and moths), Orthopterans (such as bush-crickets), Coleopterans (such as ladybirds), and Hymenopterans (such as bees).
Butterflies have a life cycle with four successive stages of metamorphosis. The egg is laid on one plant: the host plant. After a few days, the egg will hatch and a larva will appear: it’s a caterpillar. This will eat the leaves of its host plant and it will shed its skin four to six times. When the caterpillar has finished developing, it will go through a metamorphosis. For butterflies, this is called a chrysalis. The caterpillar surrounds itself with a hard case, which it has fixed to a support. Sometimes, this chrysalis is encased in a silk cocoon that it weaves with its saliva glands. Important transformations occur inside the chrysalis, some organs will wither away, such as digestive organs, and others will develop, such as legs, wings, antennae … When the chrysalis has finished its transformation, and if the weather is favorable, the chrysalis will split open and free the imago: the butterfly.
Orthopterans have an incomplete metamorphosis: the immature insect that comes out of the egg is very similar to the adult insect, but it will undergo a series of moults where the wings will grow and the insect will become mature.
Coleopterans, or beetles, undergo complete metamorphosis in four stages. The egg is laid on a substance needed for the life of the larva, (in the earth, on a plant, in compost …). After several days, the egg will hatch and a larva will appear. It will feed itself and undergo a series of moults. When it has finished its development, it will undergo a transformation, and when these are finished, and if the weather is favorable, the adult will appear.
Hymenopterans, (ants, bees and wasps), also have a four-stage metamorphosis. The egg is laid. After a few days, the egg will hatch and a larva will appear. This is the larval stage. The larva will be fed by the workers, (if they are a social insect), or alone in its micro-habitat if it is not a social insect. When the larva is fully developed, it will undergo transformations, and when these are finished, the imago will appear.