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Arixeniina

   

Forficulina

    The fossil record of the Dermaptera starts in the Late Triassic to Early Jurassic period about 208 million years ago 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.[14] The theorized stem group of the Dermaptera are the Protelytroptera. These insects, which resemble modern Blattodea, or cockroaches owing to shell-like forewings and the large, unequal anal fan, are known from the Permian of North America, Europe and Australia. There are no fossils from the Triassic when the morphological changes from Protelytroptera to Dermaptera took place.[42] The most likely, and most closely resembling, related order of insects is Notoptera, theorized by Giles in 1963. However, other arguments have been made by other authors linking them to Phasmatodea, Embioptera, Plecoptera, and Dictyoptera.[11]

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.[43] 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.[14]

Some evidence of early evolutionary history is the structure of the antennal heart,

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.[43] 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.[14]

Some evidence of early evolutionary history is the structure of the antennal heart, a separate circulatory organ consisting of two ampullae, or vesicles,[44] that are attached to the frontal cuticle to the bases of the antennae.[45] 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.[46]

Molecular studies suggest that this order is the sister to Plecoptera or to Ephemeroptera.[47]

The characteristics which distinguish the order Dermaptera from other insect orders are:[48]

  • General body shape: Elongate; dorso-ventrally flattened.
  • Head: Prognathous. Antennae are segmented. Biting-type mouthparts. Ocelli absent. Compound eyes in most species, reduced or absent in some taxa.
  • Appendages: Two pairs of wings normally present. The forewings are modified into short smooth, veinless tegmina. Hindwings are membranous and semicircular with The overwhelming majority of earwig species are in Forficulina, grouped into nine families of 180 genera,[42] including Forficula auricularia, the common European Earwig. Species within Forficulina are free-living, have functional wings and are not parasites. The cerci are unsegmented and modified into large, forceps-like structures.

    The first epizoic species of earwig was discovered by a London taxidermist on the body of a Malaysian hairless bulldog bat in 1909, then described by Karl Jordan. By the 1950s, the two suborders Arixeniina and Hemimerina had been added to Dermaptera.[16]

    Arixeniina represents two genera, Arixenia and Xeniaria, with a total of five species in them. As with Hemimerina, they are blind and wingless, with filiform segmented cerci. Hemimerina are viviparous ectoparasites, preferring the fur o

    The first epizoic species of earwig was discovered by a London taxidermist on the body of a Malaysian hairless bulldog bat in 1909, then described by Karl Jordan. By the 1950s, the two suborders Arixeniina and Hemimerina had been added to Dermaptera.[16]

    Arixeniina represents two genera, Arixenia and Xeniaria, with a total of five species in them. As with Hemimerina, they are blind and wingless, with filiform segmented cerci. Hemimerina are viviparous ectoparasites, preferring the fur of African rodents in either Cricetomys or Beamys genera.[43] Hemimerina also has two genera, Hemimerus and Araeomerus, with a total of 11 species.[43]

    Dermaptera is relatively small compared to the other orders of Insecta, with only about 2,000 species, 3 suborders and 15 families, including the extinct suborders Archidermaptera and Eodermaptera with their extinct families Protodiplatyidae, Dermapteridae, Semenoviolidae, and Turanodermatidae. The phylogeny of the Dermaptera is still debated. The extant Dermaptera appear to be monophyletic and there is support for the monophyly of the families Forficulidae, Chelisochidae, Labiduridae and Anisolabididae, however evidence has supported the conclusion that the former suborder Forficulina was paraphyletic through the exclusion of Hemimerina and Arixeniina which should instead be nested within the Forficulina.[42][49] Thus, these former suborders were eliminated in the most recent higher classification.

    Relationship with humans

    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.[50] Earwigs have been rarely known[51] to crawl into the ears of humans, but they do not lay eggs inside the human body or human brain.[52][50] Earwigs have been rarely known[51] to crawl into the ears of humans, but they do not lay eggs inside the human body or human brain.[52][53]

    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 earwi

    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,[54] 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 3–11 mm (0.12–0.43 in) in diameter.[55]