Butterflies are one of the biggest groups within the class of insects; about 100.000 species are known. They inhibit all parts of the earth were plants can be found.
Butterflies are built very uniformly and show highly developed characteristics. They possess 2 forewings and 2 hind wings. The forewings are placed lateral behind the head with the hind wings placed behind. The less gorgeous moths form the larger group; in this the forewings are situated above the hind wings. If the moth flies it expands the lower wings. The transparent wing membrane carries scales which are grouped like bricks.
Anatomy of butterflies
Like all insects´ the butterfly´s body is divided into three parts: head, thorax and abdomen.
The ball-shaped head carries important sense organs. Compound eyes enable the butterfly to orientate itself. The antennae are built very differently (e.g. feathery to increase surface) and serve as smelling organs. The antennae of males are developed higher than those of females as they have to be able to detect food sources as well as sexual attractants. The taste organs are placed on the labial palp on both sides of the rolled-in proboscis. With this long proboscis the butterfly is able to sip the sweet nectar out of long blossom tubes; the proboscis is therefore enrolled.
The thorax consists of 3 parts. It carries 2 forewings, 2 hind wings and 3 pairs of legs. Like all insect´s the butterfly´s leg consist of several sections carrying sticking soles and claws at the end.
The abdomen consists of many segments and contains digestive and generative organs.
Males carry a complex pairing accessory at the end of the body which is characterized by locking pliers which differ from species to species. Females – especially those of moths – carry adenoids at the end of the abdomen which excrete sexual attractants which enable the females to allure male individuals even over a big distance. This is necessary because the sexes are not able to recognize each other by seeing.
Reproduction
Wings, body and legs carry clusters of scales of special shape and colour which are connected to adenoids. These excrete attractants – also called pheromones – which serve to attract the opposite sex. In places with low populations – if only few animals are living in one region – the butterflies arrange so called rendezvous-places where the animals meet every year in pairing time to courtship.
Development
Butterflies are sexually separated and go through a complete metamorphosis: egg ? larva/caterpillar ? pupa ? imago (complete animal).
At first the Imago lays the egg(s) onto a forage plant. Number, size, form and colour differ from species to species; the moment of hatching of the larva – called caterpillar – and its pupation do as well. It is certain that caterpillars have two strong mandibles which they use to gnaw parts of the forage plant. Colouration and markings serve as camouflage and defence. Caterpillars moult 4-5 times on the average, pupating directly after the last skinning. Some larvae or pupae even winter in the ground. The metamorphosis from pupa to butterfly takes place in the protection of the pupae cyst and happens either on the ground, on a branch, in a nest with other pupae or – like it mostly happens with moths – in the ground. This period of time is called pupa dorm. After the complete butterfly has hatched, its wings are still folded. It pumps them up with air and blood until they became hard and completely tense. Now the imago flies away; soon it will perform a display flight and mate.
There´s is another important speciality called seasonal dimorphism. Some species of butterfly produce two generations. The caterpillars of the first generation hatch in spring in the beginning of the summer at the latest; they pupate and the adults hatch in the same year. Pupae or caterpillars of the second generation winter and the imagos do not hatch until the next year. The first and the second generation of the butterflies look different from each other. This caused big problems in identifying for me.
The caterpillar
In the body of the caterpillar lots of space is captured by the big bowel. Thin tubes – which function as kidney – flow in the bowel´s end. Above this lies the heart which is shaped like a tube. Under the heart lies a string of nerves which begins in the brain and forms the ventral marrow. The channels of the spinning gland – which takes up much room inside the caterpillar as well – end through the stoma. This gland produces the gossamers used to build cocoons and other things.
I have always asked myself why the caterpillars are never out of breath after coiling up. The caterpillar breathes over the entire length of the body. It has holes – so called spiracles – on both sides of the body (in the first breast and on nearly all segments in the abdomen) which are often coloured. These are openings which are used to breath, they are the starting point for chitin stabilised air channels (trachea) which draw through the whole body. They form the pneumatic system. The trachea can be compressed by blood pressure, in this way the used air is "exhaled" and fresh air might be absorbed by low pressure. Nevertheless the air can not be transported very far in the body with this method.
I will now come to the eyes of the caterpillar: caterpillars can hardly see each other. They have 6 eyes – situated low on the head – with each of them corresponding to a complex eye. Caterpillars are able to perceive polarised light and are able to sense direction, movement and distance. The perception of light via the skin serves as orientation when moving and as camouflage in a resting position.
The mouth parts of the caterpillar are used to examine, dissect and hackle the food. The stoma is placed on the bottom of the caterpillar´s head. It is concealed by the upper lip. Behind this lie the two mandibles (on the right and the left) which contain a cutting and a chewing edge. Below this lie the maxillae. The mouthparts are completed by the labium which consists of two parts that coalesced and carries a spinning wart in its middle. Every maxilla and every side of the labium carries structured palps which are always moving and serve to test the food. They contain gustatory oranges with separated sensorial cells to recognize food. The two antennae – situated under the simple eyes – serve to prove food as well. They contain sensorial organs which serve to perceive temperature, atmospheric humidity and smells.
List of Species threatened in Central Europe
| (German) Name | Caterpillar | Matching Plant of the Caterpillar (in German) |
Imago | |
| Admiral |  |
Brennnessel Distel |
 |
|
| Apollo |  |
Fetthenne |  |
|
| Distelfalter |  |
Brennnessel Distel |
 |
threatened |
| Großer Fuchs |  |
Weide |  |
very threatened |
| Kleiner Fuchs |  |
Brennnessel |  |
|
| Kaisermantel |  |
Himbeere Veilchen |
 |
threatened |
| Resedafalter |  |
Ackersenf Kresse |
 |
Migrant |
| Schwalbenschwanz |  |
Wilde Möhre |  |
threatened |
| Segelfalter |  |
Weißdorn |  |
population shrinks dramatically |
| Zitronenfalter |  |
Faulbaum |  |
