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Most phylogenetically advanced insects have two pairs of wings located on the second and third thoracic segments. [1]: 22–24 Insects are the only invertebrates to have developed flight capability, and this has played an important part in their success. Insect flight is not very well understood, relying on turbulent aerodynamic effects. The ...
In some insect pupae, like the mosquitoes', the head and thorax can be fused in a cephalothorax. Members of suborder Apocrita (wasps, ants and bees) in the order Hymenoptera have the first segment of the abdomen fused with the thorax, which is called the propodeum .
The thoracic segments have one ganglion on each side, which are connected into a pair, one pair per segment. This arrangement is also seen in the abdomen but only in the first eight segments. Many species of insects have reduced numbers of ganglia due to fusion or reduction. [8]
Two thoracic segments are fused into the head; one thoracic segment is in the posterior tagma. Other kinds of copepod also have two tagmata but formed by different segments. The development of distinct tagmata is believed to be a feature of the evolution of segmented animals, especially arthropods. In the ancestral arthropod, the body was made ...
Accordingly, in these insects, the functional thorax is composed of four segments, and is therefore typically called the mesosoma to distinguish it from the "thorax" of other insects. Each thoracic segment in an insect is further subdivided into various parts, the most significant of which are the dorsal portion (the notum), the lateral portion ...
Abdominal segments three through six and ten may each bear a pair of legs that are more fleshy. [21] The thoracic legs are known as true legs and the abdominal legs are called prolegs. [64] The true legs vary little in the Lepidoptera except for reduction in certain leaf-miners and elongation in the family Notodontidae.
Thoracic and abdominal sterna of a beetle. A Mesosternum, B Metasternum, 1 first abdominal sternite, 2-6 rest of sternites. The sternum (pl.: sterna) is the ventral portion of a segment of an arthropod thorax or abdomen. In insects, the sterna are usually single, large sclerites, and external.
Insects have spiracles on their exoskeletons to allow air to enter the trachea. [1] [page needed] In insects, the tracheal tubes primarily deliver oxygen directly into the insects' tissues. The spiracles can be opened and closed in an efficient manner to reduce water loss. This is done by contracting closer muscles surrounding the spiracle.