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A tegmen (: tegmina) designates the modified leathery front wing on an insect particularly in the
The term ''tegmen'' refers to a miscellaneous and arbitrary group of organs in various orders of insects; they certainly are homologous in the sense that they all are derived from insect forewings, but in other senses they are analogous; for example, the evolutionary development of the short elytra of the Dermaptera shared none of the history of the development of tegmina in the Orthoptera, say. Also, in some other insects fore- and hindwings differ both in texture and their role in flight, but are not universally regarded as tegmina. For example, the
Probably the major role of tegmina in general is that of protecting the hindwings when folded. In many insects they also are important in camouflage and in displays, especially defensive display, where the tegmina are drab, but cover
File:Snowytreecricket.JPG, Snowy tree cricket
File:Gryllus01.jpg, A male field cricket, with tegmina raised for maximal sound production, "sings" facing into the entrance to his burrow; it serves as a
orders
Order, ORDER or Orders may refer to:
* A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica
* Categorization, the process in which ideas and objects are recognized, differentiated, and understood
* H ...
Dermaptera (earwigs
Earwigs make up the insect order Dermaptera. With about 2,000 species in 12 families, they are one of the smaller insect orders. Earwigs have characteristic cerci, a pair of forceps-like pincers on their abdomen, and membranous wings folde ...
), Orthoptera
Orthoptera () is an order of insects that comprises the grasshoppers, locusts, and crickets, including closely related insects, such as the bush crickets or katydids and wētā. The order is subdivided into two suborders: Caelifera – gras ...
(grasshopper
Grasshoppers are a group of insects belonging to the suborder Caelifera. They are amongst what are possibly the most ancient living groups of chewing herbivorous insects, dating back to the early Triassic around 250 million years ago.
Grassh ...
s, cricket
Cricket is a Bat-and-ball games, bat-and-ball game played between two Sports team, teams of eleven players on a cricket field, field, at the centre of which is a cricket pitch, pitch with a wicket at each end, each comprising two Bail (cr ...
s and similar families), Mantodea
Mantises are an Order (biology), order (Mantodea) of insects that contains List of mantis genera and species, over 2,400 species in about 460 genera in 33 families. The largest family is the Mantidae ("mantids") ...
(praying mantis
Mantises are an order (Mantodea) of insects that contains over 2,400 species in about 460 genera in 33 families. The largest family is the Mantidae ("mantids"). Mantises are distributed worldwide in temperate ...
), Phasmatodea
The Phasmatodea (also known as Phasmida or Phasmatoptera) are an Order (biology), order of insects whose members are variously known as stick insects, stick bugs, walkingsticks, stick animals, or bug sticks. They are also occasionally referred ...
(stick and leaf insects) and Blattodea
Blattodea is an order (biology), order of insects that contains cockroaches and termites. Formerly, termites were considered a separate order, Isoptera, but genetics, genetic and molecular evidence suggests they evolved from within the cockroach ...
(cockroach
Cockroaches (or roaches) are insects belonging to the Order (biology), order Blattodea (Blattaria). About 30 cockroach species out of 4,600 are associated with human habitats. Some species are well-known Pest (organism), pests.
Modern cockro ...
es).
It is also a term used in botany to describe the delicate inner protective layer of a seed, and in zoology to describe a stiff membrane on the upper surface of the crown of a crinoid
Crinoids are marine invertebrates that make up the class Crinoidea. Crinoids that remain attached to the sea floor by a stalk in their adult form are commonly called sea lilies, while the unstalked forms, called feather stars or comatulids, are ...
.
In vertebrate anatomy it denotes a plate of thin bone forming the roof of the middle ear
The middle ear is the portion of the ear medial to the eardrum, and distal to the oval window of the cochlea (of the inner ear).
The mammalian middle ear contains three ossicles (malleus, incus, and stapes), which transfer the vibrations ...
.
The nature of tegmina
The term ''tegmen'' refers to a miscellaneous and arbitrary group of organs in various orders of insects; they certainly are homologous in the sense that they all are derived from insect forewings, but in other senses they are analogous; for example, the evolutionary development of the short elytra of the Dermaptera shared none of the history of the development of tegmina in the Orthoptera, say. Also, in some other insects fore- and hindwings differ both in texture and their role in flight, but are not universally regarded as tegmina. For example, the hemelytra
An elytron (; ; : elytra, ) is a modified, hardened forewing of beetles (Coleoptera), though a few of the true bugs (Hemiptera) such as the family Schizopteridae are extremely similar; in true bugs, the forewings are called hemelytra (sometimes ...
of some Hemiptera
Hemiptera (; ) is an order of insects, commonly called true bugs, comprising more than 80,000 species within groups such as the cicadas, aphids, planthoppers, leafhoppers, assassin bugs, bed bugs, and shield bugs. They range in size from ...
have been called tegmina by some authorities, but not by most modern authors.
Entomologists do not customarily refer to the forewing of a beetle as a ''tegmen''; the term for beetles' forewings is ''elytra
An elytron (; ; : elytra, ) is a modified, hardened forewing of beetles (Coleoptera), though a few of the true bugs (Hemiptera) such as the family Schizopteridae are extremely similar; in true bugs, the forewings are called hemelytra (sometime ...
''.
The function of tegmina
Probably the major role of tegmina in general is that of protecting the hindwings when folded. In many insects they also are important in camouflage and in displays, especially defensive display, where the tegmina are drab, but cover aposematic
Aposematism is the Advertising in biology, advertising by an animal, whether terrestrial or marine, to potential predation, predators that it is not worth attacking or eating. This unprofitability may consist of any defenses which make the pr ...
displays that are startling when suddenly uncovered. Sometimes, as in some mantids, the tegmina crossed over the back are not striking, but when suddenly raised, act as a threatening display resembling a pair of eyes.
Tegmina do not play a major active, flapping role in flying, though they are aerodynamically significant in insects such as migratory locusts that fly vigorously for long distances. This is probably the main justification for distinguishing between say, the forewings of cockroaches, which are called tegmina, and the forewings of some Neuroptera, which though stiffer than the rear wings, are flapped in flight.
Tegmina and sound
Tegmina, generally being stiffer than the rear wings, are used as sound boards by many species of insects, especially Orthoptera; in many locusts they make a crackling noise in flight, and in many crickets, tree crickets, and even mole crickets, the tegmina have undergone marked anatomical adaptations, often asymmetric, for sound production.resonator
A resonator is a device or system that exhibits resonance or resonant behavior. That is, it naturally oscillates with greater amplitude at some frequencies, called resonant frequencies, than at other frequencies. The oscillations in a reso ...
.
References
{{reflist Insect anatomy he:כנפי חפיה