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What defines a butterfly?

Lepidoptera (Greek lepis, lepidos=scale, pteron=wing)

A butterfly is an insect. It has a head, a thorax with three segments and an abdomen with ten segments. The genitals are in the two last segments of the abdomen. The thorax segments each have a pair of legs, so the butterfly has six legs, and the two posterior segments generally have a pair of wings. The head has compound eyes, often also simple eyes above the compound eyes, and a pair of antennae between them. The main task of the male’s antennae is to sense the female’s pheromones. The female chooses a suitable plant for the larvae to feed on using its antennae. 

Butterflies undergo complete metamorphosis (egg, larva, pupa and adult) and the different life stages have different tasks. The egg and the pupa are transformation and resting stages. A female generally lays hundreds of eggs; the Large Yellow Underwing can even lay 1500 eggs.  The larva (young, adolescent and fully-grown) feeds and often gathers spare nutrition for the adult stage. Many butterflies do not feed at all as adults. The task of the adult butterfly is to reproduce and spread.

Butterflies are poikilotherms and have a watertight skin, a waxy cuticle, and can close their spiracles. Butterflies are generally capable of flying. About 90 % of butterflies fly during the night, and therefore moths have developed an organ to detect sounds made by bats.

Butterflies can be told apart from other insects from the fact that they have scales, which cover the wings and give the butterflies their characteristic colors. The butterflies also have a proboscis that is kept coiled up under the head. Butterflies are usually herbivores, but can as well suck on vertebrate feces and secretions from carcasses. Butterflies live in many different kinds of habitats.

The first butterflies began to fly on Earth during the Cretaceous, approximately 90 million years ago. Many of the features of the butterfly fauna in Finland were caused by the Ice Age. The glaciation 20 000 years ago wiped out the butterflies in our area and all our butterfly species have gradually returned during ca 10 000 years after the last glaciation. Typical for the Finnish butterfly fauna is that species from east and south meet here.   

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Updated 22/11/2016 | Send feedback | Print