Flying insects
| Flying insects | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
.jpg)
|
||||||||||
| Systematics | ||||||||||
|
||||||||||
| Scientific name | ||||||||||
| Pterygota | ||||||||||
| Gegenbaur , 1878 |
When flying insects (Pterygota) are all insects (Insecta) summarizes which with wings are equipped. This includes the species that have lost their ability to fly in the course of evolution . Examples of this are the fleas or the animal lice . By far the largest part of the insects belong to the flying insects. The only exceptions are the non-flightable urine insects with the order of rock jumpers (Archaeognatha) and fish (Zygentoma).
A number of morphological and physiological changes are associated with the development of functional wings. For this reason, it can be assumed without a doubt that this development took place only once in the course of insect evolution and that all flying insects can be traced back to a common parent species.
Structure and development of the wings
The wings represent a thin plate of chitin , which is criss-crossed with trachea . Two theories compete with each other to create it. Either they have developed from a flattening of the side plates (paranota) on all three breast segments ( thorax ), or they originate from outgrowths of the pleuras located laterally between the dorsal nota and the ventral sterna, including the leg systems. More recent theories combine both hypotheses, according to which different parts of the wings come from one or the other structure. Arguments for this are provided by finds of Paleozoic insect larvae, which presumably had flexible wing sheaths connected to the trunk . Flying insects living today only have two pairs of wings, one on the second and one on the third thorax segment. A third pair of wings was found in fossils in the Palaeodictyoptera and the (dragonfly-like) Geroptera , which also had small, possibly not fully mobile wings or wing-like structures on the first thoracic segment.
The trachea for supplying the wings branch off from the leg trachea. Since the wings are designed as a duplication (i.e. doubling) of the body wall, the trachea also lie in these two layers as a network of veins. The wings are connected to the thorax by a complex joint , to which the dragonflies also attach the muscles directly (direct flight muscles). In the far more common variant, the flapping of the wings is achieved by bulging and retracting the chest segment (indirect flight muscles). The formation of muscle attachment points in the chest segments using chitin strips is also necessary.
Ontogeny of the flying insects
All flying insects are characterized by a metamorphosis , since the larvae or nymphs never have wings. This can take place gradually with the moulting (incomplete metamorphosis in the hemimetabolic insects ) or by a complete reconstruction of the insect in a pupal rest (complete metamorphosis in the holometabolic insects )
Systematics and taxonomy
The systematics and taxonomy are described in the systematics of insects .
literature
- Bernhard Klausnitzer : Pterygota, flying insects. In: Wilfried Westheide , Reinhard Rieger (Ed.): Special Zoology. Part 1: Protozoa and invertebrates. Gustav Fischer, Stuttgart et al. 1996, ISBN 3-437-20515-3 , p. 627 ff.
