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An antenna is considered segmented if each of the annuli is separate from those around it and has individual muscle attachments. Flagellate antennae, on the other hand, have muscle attachments only around the base, acting as a hinge for the flagellum—a flexible string of annuli with no muscle attachment. [5]
The subphylum Hexapoda (from Greek for 'six legs') or hexapods comprises the largest clade of arthropods and includes most of the extant arthropod species. It includes the crown group class Insecta (true insects), as well as the much smaller clade Entognatha, which includes three classes of wingless arthropods that were once considered insects: Collembola (springtails), Protura (coneheads) and ...
Two sets of muscles move the mandibles in the coronal plane of the mouth: abductor muscles move insects' mandibles apart ; adductor muscles bring them together . They do this mainly in opening and closing their jaws in feeding, but also in using the mandibles as tools, or possibly in fighting.
Some evidence indicates the Protura are basal to all other hexapods, [6] although not all researchers consider them Hexapoda, rendering the monophyly of Hexapoda unsettled. [7] Uniquely among hexapods, proturans show anamorphic development, whereby body segments are added during moults. [8] [page needed]
Tömösváry organ (arrow) on the head of a symphylan, just behind the base of an antenna. Tömösváry organs, also known as temporal organs or postantennal organs [1] are specialized paired sensory organs found in certain groups of myriapods (e.g. centipedes and millipedes) and hexapods (e.g. springtails), located on the head near the base of the antennae.
Springtails (class Collembola) form the largest of the three lineages of modern hexapods that are no longer considered insects.Although the three lineages are sometimes grouped together in a class called Entognatha because they have internal mouthparts, they do not appear to be any more closely related to one another than they are to all insects, which have external mouthparts.
In other winged insects, flight muscles attach to the thorax, which make it oscillate in order to induce the wings to beat. Of these insects, some ( flies and some beetles ) achieve very high wingbeat frequencies through the evolution of an "asynchronous" nervous system, in which the thorax oscillates faster than the rate of nerve impulses.
An insect uses its digestive system to extract nutrients and other substances from the food it consumes. [3]Most of this food is ingested in the form of macromolecules and other complex substances (such as proteins, polysaccharides, fats, and nucleic acids) which must be broken down by catabolic reactions into smaller molecules (i.e. amino acids, simple sugars, etc.) before being used by cells ...