Earwig

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Earwig Fossil range: 199–0 Ma PreЄ Є O S D C P T J K Pg N Jurassic to Recent
Common earwig, Forficula auricularia
Scientific classification
Kingdom: Animalia Phylum: Arthropoda Subphylum: Hexapoda Class: Insecta Order: Dermaptera De Geer, 1773
Families
Suborder Archidermaptera † Protodiplatyidae Suborder Arixeniina Arixeniidae Suborder Forficulina Anisolabididae Apachyidae Chelisochidae Diplatyidae Forficulidae Karschiellidae Labiduridae Labiidae Pygidicranidae Suborder Hemimerina Hemimeridae

Earwig is the common name given to the insect order Dermaptera characterized by membranous wings folded underneath short forewings (hence the literal name of the order—"skin wings"). The abdomen extends beyond the wings, and frequently, ends in a pair of forceps-like structures called cerci. The order is relatively small among Insecta, with about 1,800 recorded species in 10 families. Earwigs are found around the world. There is no evidence that they transmit disease to humans or other animals.

Contents 1 Taxonomy 1.1 Etymology 2 Distribution and habitat 3 Appearance and behavior 4 References 5 More information 6 External links

[edit] Taxonomy

The order Dermaptera contains around 1,800 species,^[1] despite a record of fossilization that began 208 million years ago and numerous extant species.^[2][3] Although this fossil record is very sparse, four suborders within Dermaptera have been established.^[4] The actual phylogeny of the suborders remains a topic of debate, however, as all three extant species have distinct morphologies yet molecular evidence suggests Forficulina is paraphyletic through the exclusion of Hemimerina.^[5][1]

• Archidermaptera: An extinct group whose fossil record is known only from the Jurassic, and is believed to be sister to the remaining earwig species. This suborder has tarsi with five segments (unlike the three found in the other suborders) as well as unsegmented cerci.^[2]
• Arixeniina: Represented by 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. They are ectoparasites of various Southeast Asian bats, preferring guano from the genus Cheiromeles (i.e., "naked bulldog bats").^[1]
• Forficulina: Contains the overwhelming majority of earwig species, grouped into nine families of 180 genera,^[5] including Forficula auricularia, the common European Earwig. Species within Forficulina have functional wings and are not parasites.^[1] The cerci are unsegmented and modified into large, forcep-like structures.^[2]
• Hemimerina: Represented by two genera, Hemimerus and Araeomerus, with a total of 11 species. They are wingless and blind, with filiform segmented cerci. Hemimerina are viviparous ectoparasites, preferring the fur of African rodents in either Cricetomys or Beamys genera.^[1]

[edit] Etymology

The scientific name for the order, Dermaptera, is Greek in origin, stemming from the words dermatos, meaning skin, and pteron, or wing. It was coined by Charles De Geer in 1773.^[5] The far more common term, earwig, is derived from the Old English ēare, which means "ear", and wicga, which means "insect." The name comes from the old wives' tale that earwigs burrowed into the brains of humans through the ear and therein lay their eggs.^[6]

Other languages have words based on the same premise: German Ohrwurm or "Ohrenhoehler", Dutch "Orenkruiper" (Oren means ears and kruiper means crawler), French perce-oreille,^[7] Danish ørentviste, Slovak ucholak (ucho = ear, lak = scare), Romanian urechelnita and Hungarian fülbemászó ("crawler-into-the-ear"). English has derived a verb from this, to earwig, meaning "to fill someone's mind with prejudice by insinuations" or "to attempt to influence by persistent confidential argument or talk".^[8] The German word Ohrwurm, has the derived meaning of earworm.^[9][10] Hungarian also uses the phrase fülbemászó dallam meaning "a catchy melody".^[11] Some dialects of Swedish have related names for the earwig, but standard Swedish, by contrast, uses the word tvestjärt, which translates as "two-tail".^[12], not unlike the Geordie forkytail.

[edit] Distribution and habitat

The majority of Dermapteran species belong to the family Forficulina, and those that do not are small and often parasitic. Thus, nearly all human encounters with earwigs are with Forficulina. The common European earwig Forficula auricularia, for example, was

introduced to North America from Europe in 1907^[13] and has spread to every continent except Antarctica, although they tend to prefer warmer, more tropical regions.^[1][2] Earwigs are nocturnal, and typically spend the daytime hours hiding in small, dark, and often moist areas. At night, they feed on a variety of agricultural plants, such as legumes, lettuce, and corn. They also prey on other arthropods, such as mites, aphids, and Sminthurus viridis, the Lucerne flea.^[14][13]

[edit] Appearance and behavior

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Most earwigs are elongated, flattened, and are dark brown. Lengths are mostly in the quarter- to half-inch range (10–14 mm), with the Saint Helena Giant Earwig reaching three inches long (80 mm). Cerci range from nonexistent to long arcs up to one-third as long as the rest of the body. Mouthparts are designed for chewing, as in other orthopteroid insects. Flight capability in Dermaptera is varied, as there are species with and without wings. In those earwigs that have wings (are not apterous), the hindwings are folded in a complex fashion, so that they fit under the forewings. Most species of winged earwigs are capable of flight, yet earwigs rarely do.

The abdomen of the earwig is flexible and muscular. It is capable of maneuvering as well as opening and closing the forceps. The forceps are used for a variety of purposes. In some species, the forceps have been observed in use for holding prey, and in copulation. The forceps tend to be more curved in males than in females.

Most earwigs found in Europe and North America are of the species Forficula auricularia, the European or common earwig, which is distributed throughout the cooler parts of the northern hemisphere. This species feeds on other insects, plants, ripe fruit, and garbage. Plants that they feed on typically include clover, dahlias, zinnias, butterfly bush, hollyhock, lettuce, cauliflower, strawberry, sunflowers, celery, peaches, plums, grapes, potatoes, roses, seedling beans and beets, and tender grass shoots and roots; they have also been known to eat corn silk, damaging the corn. Typically they are a nuisance because of their diet, but normally do not present serious hazards to crops. Some tropical species are brightly colored. Occasionally earwigs are confused with cockroaches because of their cerci and their long antennae.

Earwigs are generally nocturnal and can be seen patrolling household walls and ceilings. Interaction with earwigs at this time results in a defensive free fall to the ground below, and the subsequent scramble to a nearby cleft or crevice.

Earwigs are also drawn to damp conditions. During the summer, they can be found around sinks and in bathrooms. Earwigs tend to gather in shady cracks or openings or anywhere that they can remain concealed during daylight hours. Picnic tables, compost and waste bins, patios, lawn furniture, window frames, or anything with minute spaces (even artichoke blossoms) can potentially harbor them. Upon gaining entry to the basement and living areas of the home, earwigs can easily find cover in undisturbed magazine and newspaper piles, furniture/wickerwork, base boards, carpeted stairways, pet food dishes, and even inside DVD cases and keyboards.

Earwigs have been considered in some ways a beneficial part of gardens, especially when they prey on other insects, but they can become a nuisance because of their habit of positioning themselves within leaves and feeding on soft plant tissues. Diatomaceous earth is a possible long term earwig repellent.

[edit] References

[edit] More information

• Grimaldi, D. and Engel, M.S. (2005), Evolution of the Insects, Cambridge University Press, ISBN 0-521-82149-5 
• Engel, M.S. and F. Haas (2007), "Family-group names for earwigs (Dermaptera)", American Museum Novitates 3567: 1–20, doi:10.1206/0003-0082(2007)539[1:FNFED]2.0.CO;2 
• J. D. Taylor (1978), "The earwig: the truth about the myth", Rocky Mountain Medical Journal 75: 37–38 
• Rod Serling's episode of Night Gallery, "The Caterpillar
• Weems Jr HV, Skelley PE. (2007). European earwig, Forficula auricularia Linnaeus. Featured Creatures. EENY-32. http://entomology.ifas.ufl.edu/creatures/veg/european_earwig.htm (27 February 2009).
• (^{[dead link]}) Pest Organisms of the Puget Sound Region: Earwigs, Cascade Pest Control, http://www.cascadepest.com/pest.htm#earwigs 
• (PDF) Keep earwigs away, Islington Council, http://www.islington.gov.uk/DownloadableDocuments/Environment/Pdf/pestearwig.pdf 
• Natural Insect Pest Control, eartheasy.com, http://www.eartheasy.com/live_natpest_control.htm 
• (^{[dead link]} – ^{Scholar search}) Earwig Fact Sheet and Gallery, Harvard University, http://www.uos.harvard.edu/ehs/pest_earwig.shtml 

[edit] External links

Wikispecies has information related to: Dermaptera

The Wikibook Dichotomous Key has a page on the topic of Dermaptera

• Tree of Life info for Dermaptera
• CSIRO Dermaptera page
• "Earwigs eat through your brain" urban legend debunked
• What's That Bug's Earwig Page
• Harvard University information on earwigs^{[dead link]}
• Earwig Research Centre
• BBC Science and Nature Wildfacts
• ringlegged earwig on the UF / IFAS Featured Creatures web site