Құрлықашалықтар: Биологиясы, таралуы және эволюциясы

Order of insects

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 forcep like pincers on their abdomen, and membranous wings folded underneath short, rarely used forewings, hence the scientific order name, "skin wings". Some groups are tiny parasites on mammals and lack the typical pincers. Earwigs are found on all continents except Antarctica. Earwigs are mostly nocturnal and often hide in small, moist crevices during the day, and are active at night, feeding on a wide variety of insects and plants. Damage to foliage, flowers, and various crops is commonly blamed on earwigs, especially the common earwig Forficula auricularia. Earwigs have five molts in the year before they become adults. Many earwig species display maternal care, which is uncommon among insects. Female earwigs may care for their eggs; the ones that do will continue to watch over nymphs until their second molt. As the nymphs molt, sexual dimorphism such as differences in pincer shapes begins to show. Extant Dermaptera belong to the suborder Neodermaptera, which first appeared during the Cretaceous. Some earwig specimen fossils are placed with extinct suborders Archidermaptera or Eodermaptera, the former dating to the Late Triassic and the latter to the Middle Jurassic. Dermaptera belongs to the major grouping Polyneoptera, and are amongst the earliest diverging members of the group, alongside angel insects (Zoraptera), and stoneflies (Plecoptera), but the exact relationship among the three groups is uncertain.

The scientific name for the order, Dermaptera, is Greek in origin, stemming from the words , meaning , and (plural ), meaning It was coined by Charles De Geer in 1773. The common term, earwig, is derived from the Old English ēare, which means , and wicga, which means , or literally, Entomologists suggest that the origin of the name is a reference to the appearance of the hindwings, which are unique and distinctive among insects, and resemble a human ear when unfolded. The name is more popularly thought to be related to the old wives' tale that earwigs burrowed into the brains of humans through the ear and laid their eggs there. Earwigs are not known to purposefully climb into ear canals, but there have been anecdotal reports of earwigs being found in the ear.

Earwigs are abundant and can be found throughout the Americas and Eurasia. The common earwig was introduced into North America in 1907 from Europe, but tends to be more common in the southern and southwestern parts of the United States. found as far north as Canada, where it hides in the leaf axils of emerging plants in southern Ontario wetlands. However, other families can be found in North America, including Forficulidae (Doru and Forficula being found there), Spongiphoridae, Anisolabididae, and Labiduridae. Few earwigs survive winter outdoors in cold climates. They can be found in tight crevices in woodland, fields and gardens. Out of about 1,800 species, about 25 occur in North America, 45 in Europe (including 7 in Great Britain), and 60 in Australia. The largest extant species is the Australian giant earwig (Titanolabis colossea) which is approximately long, while the possibly extinct (declared extinct in 2014) Saint Helena earwig (Labidura herculeana) reached Earwigs are characterized by the cerci, or the pair of forceps like pincers on their abdomen; male earwigs generally have more curved pincers than females. These pincers are used to capture prey, defend themselves and fold their wings under the short tegmina. Males in the six families Karschiellidae, Pygidicranidae, Diplatyidae, Apachyidae, Anisolabisidae and Labiduridae have paired penises, while the males in the remaining groups have a single penis. Both penises are symmetrical in Pygidicranidae and Diplatyidae, but in Karschiellidae the left one is strongly reduced. Apachyidae, Anisolabisidae, and Labiduridae have an asymmetrical pair, with left and right one pointing on opposite directions when not in use. The females have just a single genital opening, so only one of the paired penises is ever used during copulation. The forewings are short oblong leathery plates used to cover the hindwings like the elytra of a beetle, rather than to fly. Most species have short and leather like forewings with very thin hindwings, though species in the former suborders Arixeniina and Hemimerina (epizoic species, sometimes considered as ectoparasites) are wingless and blind with filiform segmented cerci (today these are both included merely as families in the suborder Neodermaptera). The hindwing is a very thin membrane that expands like a fan, radiating from one point folded under the forewing. Even though most earwigs have wings and are capable of flight, they are rarely seen in flight. These wings are unique in venation and in the pattern of folding that requires the use of the cerci.

The neuroendocrine system is typical of insects. There is a brain, a subesophageal ganglion, three thoracic ganglia, and six abdominal ganglia. Strong neuron connections connect the neurohemal corpora cardiaca to the brain and frontal ganglion, where the closely related median corpus allatum produces juvenile hormone III in close proximity to the neurohemal dorsal arota. The digestive system of earwigs is like all other insects, consisting of a fore , mid , and hindgut, but earwigs lack gastric caecae which are specialized for digestion in many species of insect. Long, slender (excretory) malpighian tubules can be found between the junction of the mid and hind gut. The reproductive system of females consist of paired ovaries, lateral oviducts, spermatheca, and a genital chamber. The lateral ducts are where the eggs leave the body, while the spermatheca is where sperm is stored. Unlike other insects, the gonopore, or genital opening is behind the seventh abdominal segment. The ovaries are primitive in that they are polytrophic (the nurse cells and oocytes alternate along the length of the ovariole). In some species these long ovarioles branch off the lateral duct, while in others, short ovarioles appear around the duct. Each egg is approximately tall and wide. and on their own molts. If the mother dies before the nymphs are ready to leave, the nymphs may eat her. After five to six instars, the nymphs will molt into adults. The male's forceps will become curved, while the females' forceps remain straight. They will also develop their natural color, which can be anything from a light brown (as in the tawny earwig) to a dark black (as in the ringlegged earwig). In species of winged earwigs, the wings will start to develop at this time. The forewings of an earwig are sclerotized to serve as protection for the membranous hindwings.

Most earwigs are nocturnal and inhabit small crevices, living in small amounts of debris, in various forms such as bark and fallen logs. Species have been found to be blind and living in caves, or cavernicolous, reported to be found on the island of Hawaii and in South Africa. Food typically consists of a wide array of living and dead plant and animal matter. Under exceptional circumstances, earwigs form swarms and can take over significant areas of a district. In August 1755 they appeared in vast numbers near Stroud, Gloucestershire, UK, especially in the cracks and crevices of "old wooden buildings so that they dropped out oftentimes in such multitudes as to literally cover the floor." A similar "plague" occurred in 2006, in and around a woodland cabin near the Blue Ridge Mountains of the eastern United States; it persisted through winter and lasted at least two years.

Earwigs are mostly scavengers, but some are omnivorous or predatory. The common earwig is an omnivore, eating plants and ripe fruit as well as actively hunting arthropods. To a large extent, this species is also a scavenger, feeding on decaying plant and animal matter if given the chance. Observed prey include largely plant lice, but also large insects such as bluebottle flies and woolly aphids. Species of the suborders Arixeniina and Hemimerina are generally considered epizoic, or living on the outside of other animals, mainly mammals. In the Arixeniina, family Arixeniidae, species of the genus Arixenia are normally found deep in the skin folds and gular pouch of Malaysian hairless bulldog bats (Cheiromeles torquatus), apparently feeding on bats' body or glandular secretions. On the other hand, species in the genus Xeniaria (still of the suborder Arixeniina) are believed to feed on the guano and possibly the guanophilous arthropods in the bat's roost, where it has been found. Hemimerina includes Araeomerus found in the nest of long tailed pouch rats (Beamys), and Hemimerus which are found on giant Cricetomys rats. Earwigs are generally nocturnal, and typically hide in small, dark, and often moist areas in the daytime. They can usually be seen on household walls and ceilings. Interaction with earwigs at this time results in a defensive free fall to the ground followed by a scramble to a nearby cleft or crevice.

Earwigs are regularly preyed upon by birds, and like many other insect species they are prey for insectivorous mammals, amphibians, lizards, centipedes, assassin bugs, and spiders. European naturalists have observed bats preying upon earwigs. Another tachinid fly and parasite of earwigs, Ocytata pallipes, has shown promise as a biological control agent as well. The common predatory wasp, the yellow jacket (Vespula maculifrons), preys upon earwigs when abundant. A small species of roundworm, Mermis nigrescens, is known to occasionally parasitize earwigs that have consumed roundworm eggs with plant matter. At least 26 species of parasitic fungus from the order Laboulbeniales have been found on earwigs. The eggs and nymphs are also cannibalized by other earwigs. A species of tyroglyphoid mite, Histiostoma polypori (Histiostomatidae, Astigmata), are observed on common earwigs, sometimes in great densities; however, this mite feeds on earwig cadavers and not its live earwig transportation. Hippolyte Lucas observed scarlet acarine mites on European earwigs.

The fossil record of the Dermaptera starts in the Late Triassic to Early Jurassic period about in England and Australia, and comprises about 70 specimens in the extinct suborder Archidermaptera. Some of the traits believed by neontologists to belong to modern earwigs are not found in the earliest fossils, but adults had five segmented tarsi (the final segment of the leg), well developed ovipositors, veined tegmina (forewings) and long segmented cerci; in fact the pincers would not have been curled or used as they are now. The theorized stem group of the Dermaptera are the Protelytroptera, which are similar to modern Blattodea (cockroaches) with shell like forewings and the large, unequal anal fan, are known from the Permian of North America, Europe and Australia. No fossils from the Triassic — during which Dermaptera would have evolved from Protelytroptera — have been found. Amongst the most frequently suggested order of insects to be the closest relatives of Dermaptera is Notoptera, theorized by Giles in 1963. However, other arguments have been made by other authors linking them to Phasmatodea, Embioptera, Plecoptera, and Dictyoptera. A 2018 phylogenetic analysis found that their closest living relatives were angel insects of the order Zoraptera, with very high support. Archidermaptera is believed to be sister to the remaining earwig groups, the extinct Eodermaptera and the living suborder Neodermaptera (= former suborders Forficulina, Hemimerina, and Arixeniina). The extinct suborders have tarsi with five segments (unlike the three found in Neodermaptera) as well as unsegmented cerci. No fossil Hemimeridae and Arixeniidae are known. Species in Hemimeridae were at one time in their own order, Diploglassata, Dermodermaptera, or Hemimerina. Like most other epizoic species, there is no fossil record, but they are probably no older than late Tertiary. that are attached to the frontal cuticle near the bases of the antennae. These features have not been found in other insects. An independent organ exists for each antenna, consisting of an ampulla, attached to the frontal cuticle medial to the antenna base and forming a thin walled sac with a valved ostium on its ventral side. They pump blood by elastic connective tissue, rather than muscle.

Earwigs are fairly abundant and are found in many areas around the world. There is no evidence that they transmit diseases to humans or other animals. Their pincers are commonly believed to be dangerous, but in reality, even the curved pincers of males cause little or no harm to humans. Earwigs have been rarely known to crawl into the ears of humans, and they do not lay eggs inside the human body or human brain as is often claimed. There is a debate whether earwigs are harmful or beneficial to crops, as they eat both the foliage and the insects eating such foliage, such as aphids, though it would take a large population to do considerable damage. The common earwig eats a wide variety of plants, and also a wide variety of foliage, including the leaves and petals. They have been known to cause economic losses in fruit and vegetable crops. Some examples are the flowers, hops, red raspberries, and corn crops in Germany, and in the south of France, earwigs have been observed feeding on peaches and apricots. The earwigs attacked mature plants and made cup shaped bite marks in diameter.