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Unlike other flying animals such as birds and bats, where the wings come from the forelegs, those of insects have a completely different structure and origin. Their origin and evolutionary history are still confused and controversial. From a simple system at the beginning, the operation of the wings later proved to be incredibly complex! Origine and evolution The first known fossil winged insects are dated to the Paleozoic primary era : million years and are all terrestrial. The acquisition of wings and flight has allowed an explosion of diversity of families Hymenoptera, Lepidoptera, Diptera… , genera and species read th article.

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Unlike other flying animals such as birds and bats, where the wings come from the forelegs, those of insects have a completely different structure and origin. Their origin and evolutionary history are still confused and controversial. From a simple system at the beginning, the operation of the wings later proved to be incredibly complex! Origine and evolution The first known fossil winged insects are dated to the Paleozoic primary era : million years and are all terrestrial. The acquisition of wings and flight has allowed an explosion of diversity of families Hymenoptera, Lepidoptera, Diptera… , genera and species read th article.

The evolutionary advantage provided was gigantic: better dispersion search for food, favourable environments, etc. Two theories have been proposed to explain the origin of insect wings. According to the supporters of the second, the flight would have come from semiaquatic insects using thoracic outgrowths to skim the water, in the manner of the larvae of Ephemeroptera and Plecoptera : natural selection would have allowed them to leave the aquatic environment for that of the air. The idea is that the wings would come from modified exopodites 2nd and 3rd pairs , while the first pair would have been lost or incorporated into the thorax.

These sensory organs play a role in the control of reflexes and movements, essential parameters for flight lire this article. The origin and evolution of the wings in insects are not yet well described, they are modified and completed with palaeontological discoveries and analyses on the development of arthropods. The chest is composed of 3 segments Pro-, Meso— and Metathorax read th article. The two pairs of wings are articulated with the scleritis sclerotic exoskeleton plate dorsal tergite and lateral pleuritis thorax via a series of small sclerified elements called Pteralia or axillary structure.

The organization and number of Pteralia vary greatly between species, but a general plan can be defined. It consists of 3 axillary sclerites 1ax, 2ax and 3ax , a distal medial plate dmp , a humeral plate hp and a proximal medial plate pmp see illustration below.

Dessi — Modified by B. GILLES The wing is a cuticular membrane exoskeleton formed by the juxtaposition of two epidermal layers a dorsal and a ventral. The muscles, at the origin of the movements, are located at the base of the wing and connected to the thorax by structures of the exoskeleton: the Pteralia see previous paragraph. The functioning is thus totally different from the wings of mammals and birds where the musculature is inside the limb.

The veins travel longitudinally along the wing surface, subdividing and connecting with each other to form cells either closed fully veined or open partially veined.

The layout and design of these cells are specific to each evolutionary lineage: the classification of families and genera thus relies heavily on the use of these morphological characters. Their study also provides a lot of information on the evolutionary history of wing formation and flight adaptation from a biomechanical and aerodynamic point of view, especially since the wing structures have a higher fossilization power than the other elements of the insect.

The system adopted by the largest number is that of the English entomologist Robin J. Wootton The principle is based on the nomination of the main ribs and the numbering of their subdivisions see illustration below. It is subdivided into two, the Radiale and the Radial sector Rs , each in turn subdividing itself. The number of these subdivisions varies according to the species and are numbered example here R1, R2 and R3 and Rs1, Rs2, Rs3.

The variability of the diameter, thickness and section shape of the veins give the wing specific mechanical and bending properties. During flight, the wing undergoes stresses and deformations related to the pressure exerted by the air on its surface.

To counter these and maintain its efficiency at the wing, certain ribs, by their degree of flexibility or rigidity, play a reinforcing role. For example, the Costal rib allows the wing to remain rigid during hover flight and a highly rigid cell at its tip, the Pterostigma, prevents the wing from floating during sudden changes of direction by adding weight.

Also, in Diptera and Hymenotpera for example, the wing tips are particularly flexible — an adaptation to avoid degradation during impact or landing. Some orders have independently developed the ability to bend their wings on their abdomen Neoptera , a selected adaptation in protection as in Coleoptera : the forewings have become rigid Elytres and the hindwings fold transversely to fit under the forewings , or to facilitate ground movement. A faculty that is allowed by the presence of bending lines where the structure of the veins gives them a great flexibility.

In other orders, such as Odonata dragonflies and Ephemeroptera ephemera , the wings remain open on either side of the body when the animal is at rest. In Odonates, the wing base is simplified, the medial plates have disappeared and the sclerites have fused to form only a humeral plate and an axillary plate see illustration below. There is as much shape, ornamentation, texture and relief as there are insect species. The changes sometimes gave the wings roles other than vol. Examples Dumbbell of a diptera of the family Tipulidae Source Dipteres flies : the hindwings of the flies are atrophied and have transformed into gyroscopic organs the dumbbells or pendulums see photo and video below.

By vibrating rapidly, they develop a tension force that stabilizes the insect on a horizontal plane. Pendulums play a balancing role that allows flies to perform aerobatics and aerobatics. Sensory organs campaniform senses , located at the base of the pendulums, inform the insect about the tension forces read this article.

Grasshoppers and crickets Ensiberous Orthopters : the forewings Elytra are modified in males to produce and amplify sound. Sound, emitted by stridulation, intervenes in the recognition of sexual partners. The insect rubs striated veins stridulatory rasp on the ventral surface of the right wing and on the dorsal surface of the left wing.

One or more cells in the wing act as a sound box. The arrangement of the teeth of the rasp and the rubbing rhythm of the elytra emit a sound that is specific to each species. A second article follows this one which concerns the musculature, aerodynamics and control system in insect flight. For more information, I invite you to follow this link.

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Since the sensitivity of psyllid photoreceptors is currently not known, we used a Stavenga template for chromophore A1, the most commonly encountered chromophore in insects, to model spectral sensitivities Stavenga et al. The putative photosensitivities used to calculate photoreceptor stimulations are represented in Figure 3. Putative sensitivities of UV-blue-green photoreceptors modeled with the Stavenga template for photopigment A1 used in the calculation of photon catches in Equation 3. Statistical Analyses The influence of gender on color preference was tested using nominal logistic regression Quinn and Keough,

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