Insect scale
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Scales are present on the bodies of various insects. A notable example are the Lepidoptera, the insect order comprising moths and butterflies, which have scales on their wings and on the head, parts of the thorax and abdomen, and parts of the genitalia. The name is derived from Ancient Greek λεπίδος (scale) and πτερόν (wing). The Trichoptera (caddisflies) which are a sister group of the Lepidoptera have scales, but also possess caudal cerci on the abdomen, a feature absent in the Lepidoptera. Beetles of family Dermestidae also commonly have scales. Within the dipteran infraorder Culicomorpha, possession of a scale fringe on the posterior margin of the forewings is a proposed synapomorphy of Corethrellidae, Chaoboridae and Culicidae. Many Zygentoma and Archaeognatha have scales on their bodies, whose iridescent appearance gives certain Zygentoma the common name of silverfish.
Scales are present on the bodies of various insects. A notable example are the Lepidoptera, the insect order comprising moths and butterflies, which have scales on their wings and on the head, parts of the thorax and abdomen, and parts of the genitalia. The name is derived from Ancient Greek λεπίδος (scale) and πτερόν (wing). The Trichoptera (caddisflies) which are a sister group of the Lepidoptera have scales, but also possess caudal cerci on the abdomen, a feature absent in the Lepidoptera. Beetles of family Dermestidae also commonly have scales. Within the dipteran infraorder Culicomorpha, possession of a scale fringe on the posterior margin of the forewings is a proposed synapomorphy of Corethrellidae, Chaoboridae and Culicidae. Many Zygentoma and Archaeognatha have scales on their bodies, whose iridescent appearance gives certain Zygentoma the common name of silverfish.
Lepidoptera
The morphology of lepidopteran scales has been studied by Downey & Allyn (1975) and scales have been classified into three groups, namely: Hair-like or piliform. Blade-like or lamellar. Other variable forms. Primitive moths (non-Glossata and Eriocranidae) have 'solid' scales which are imperforate, i.e., they lack a lumen. As per Scoble (2005):
Zygentoma and Archaeognatha
The orders Zygentoma and Archaeognatha were formerly united as suborders of Thysanura, but were found to not have a sister relationship and were consequently elevated as orders. Scales are not present in the first instar in either order, appearing after one or more molts—two in Archaeognatha. The extent of scaling varies between taxa, with at least the three terminal filaments, tergites and abdominal coxites bearing scales in known Archaeognatha. Certain families of Zygentoma are scaleless.
Structure
The structure of scales differs between the two orders; Zygentoma scales have a membrane with raised ribs on their upper surface, while Archaeognatha scales contain a porous lumen formed by upper and lower plates.
Function
The scales of Zygentoma and Archaeognatha may serve anti-predator and mechanosensory functions.
Text derived from https://en.wikipedia.org/w/index.php?oldid=1374945229 under CC BY-SA 4.0; modifications have been made.