Earwigs make up theinsectorderDermaptera. With about 2,000 species[1] in 12 families, they are one of the smaller insect orders. Earwigs have characteristiccerci, a pair offorceps-likepincers 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 exceptAntarctica.
Earwigs are mostlynocturnal 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 earwigForficula auricularia.
Earwigs have fivemolts 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 overnymphs until their second molt. As the nymphs molt,sexual dimorphism such as differences in pincer shapes begins to show.
Extant Dermaptera belong to the suborderNeodermaptera, which first appeared during theCretaceous. Some earwig specimen fossils are placed with extinct subordersArchidermaptera orEodermaptera, the former dating to theLate Triassic and the latter to the Middle Jurassic. Dermaptera belongs to the major groupingPolyneoptera, 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.
Earwig diagram with wings extended and closedAn earwig crawling on wood.
Thescientific name for the order,Dermaptera, isGreek in origin, stemming from the wordsderma, meaning'skin', andpteron (pluralptera), meaning'wing'. It was coined byCharles De Geer in 1773. The common term,earwig, is derived from theOld Englishēare, which means'ear', andwicga, which means'insect', or literally,'beetle'.[2] 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.[3][4] The name is more popularly thought to be related to theold wives' tale that earwigs burrowed into the brains of humans through the ear and laid their eggs there.[5] Earwigs are not known to purposefully climb into ear canals, but there has been at least one anecdotal report of earwigs being found in the ear.[6]
Earwigs are abundant and can be found throughout theAmericas andEurasia. 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.[7]: 739 The only native species of earwig found in the north of the United States is thespine-tailed earwig (Doru aculeatum),[8] found as far north as Canada, where it hides in the leaf axils of emerging plants in southernOntariowetlands. However, other families can be found in North America, includingForficulidae (Doru andForficula being found there),Spongiphoridae,Anisolabididae, andLabiduridae.[9]
Few earwigs survive winter outdoors in cold climates. They can be found in tight crevices in woodland, fields and gardens.[7]: 739 [10] Out of about 1,800 species, about 25 occur in North America, 45 in Europe (including 7 in Great Britain), and 60 in Australia.[11]
Male earwig, external morphology. Click on image for a larger view
Most earwigs are flattened (which allows them to fit inside tight crevices, such as under bark) with an elongated body generally 7–50 millimetres (1⁄4–2 in) long.[11] The largestextant species is the Australian giant earwig (Titanolabis colossea) which is approximately 50 mm (2 in) long,[12]: 10 while the possibly extinct (declared extinct in 2014)Saint Helena earwig (Labidura herculeana) reached78 mm (3+1⁄16 in).[13] Earwigs are characterized by thecerci, or the pair offorceps-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 shorttegmina.[14] Theantennae are thread-like with at least 10 segments.[7]: 738–739
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.[15][16][17]
Earwig with right wing open
The forewings are short oblong leathery plates used to cover the hindwings like theelytra of a beetle, rather than to fly. Most species have short and leather-like forewings with very thin hindwings, though species in the former subordersArixeniina andHemimerina (epizoic species, sometimes considered as ectoparasites[18][19]) are wingless and blind with filiform segmented cerci (today these are both included merely as families in the suborder Neodermaptera).[11][20][21] 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.[22]
Theneuroendocrine system is typical of insects. There is a brain, a subesophagealganglion, three thoracic ganglia, and six abdominal ganglia. Strong neuron connections connect theneurohemal corpora cardiaca to the brain and frontal ganglion, where the closely relatedmedian 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.[23]
The reproductive system of females consist of pairedovaries,lateral oviducts,spermatheca, and agenital chamber. The lateral ducts are where the eggs leave the body, while the spermatheca is where sperm is stored. Unlike other insects, thegonopore, or genital opening is behind the seventh abdominal segment. The ovaries are primitive in that they are polytrophic (thenurse cells andoocytes alternate along the length of theovariole). In some species these long ovarioles branch off the lateral duct, while in others, short ovarioles appear around the duct.[23]
The life cycle and development of a male earwig from egg to eachinstar
Earwigs arehemimetabolous, meaning they undergo incomplete metamorphosis, developing through a series of four to sixmolts. The developmental stages between molts are calledinstars. Earwigs live for about a year from hatching. They start mating in the autumn, and can be found together in the autumn and winter. The male and female will live in a chamber in debris, crevices, or soil 2.5 centimetres (1 in) deep.[7]: 739 After mating, the sperm may remain in the female for months before the eggs are fertilized. From midwinter to early spring, the male will leave, or be driven out by the female. Afterward the female will begin to lay 20 to 80 pearly whiteeggs in two days. Some earwigs, those parasitic in the subordersArixeniina andHemimerina, areviviparous (give birth to live young); they would be fed by a sort ofplacenta.[7]: 739–740 [20] When first laid, the eggs are white or cream-colored and oval-shaped, but right before hatching they become kidney-shaped and brown.[24] Each egg is approximately1 mm (1⁄32 in) tall and0.8 mm (1⁄32 in) wide.[21]
Earwigs are among the few non-social insect species that show maternal care. The mother pays close attention to the needs of her eggs, such as warmth and protection.[7]: 739–740 [20] She faithfully defends the eggs from predators, not leaving them even to eat unless the clutch goes bad.[7]: 740 She also continuously cleans the eggs to protect them fromfungi. Studies have found that the urge to clean the eggs persists for only a few days after they are removed, and does not return even if the eggs are replaced; however, when the eggs were continuously replaced after hatching, the mother continued to clean the new eggs for up to three months.[7]: 740
Studies have also shown that the mother does not immediately recognize her own eggs. After laying them, she gathers them together, and studies have found mothers to pick up small egg-shaped wax balls or stones by accident. Eventually, the impostor eggs were rejected for not having the proper scent.[7]: 740
Female earwig in her nest, with eggs
Female earwig in her nest with newly hatched young
The eggs hatch in about seven days. The mother may assist the nymphs in hatching. When the nymphs hatch, they eat the egg casing and continue to live with the mother. The nymphs look similar to their parents, only smaller, and will nest under their mother and she will continue to protect them until their second molt. The nymphs feed on foodregurgitated by the mother,[25] and on their own molts. If the mother dies before the nymphs are ready to leave, the nymphsmay eat her.[7]: 740 [26]
After five to sixinstars, 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 thetawny earwig) to a dark black (as in theringlegged 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.[23] For protection from predators, the speciesDoru taeniatum of earwigs can squirt foul-smelling yellow liquid in the form of jets from scent glands on the dorsal side of the third and fourth abdominal segment. It aims the discharges by revolving the abdomen, a maneuver that enables it simultaneously to use its pincers in defense.[27]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".[28] A similar "plague" occurred in 2006, in and around a woodland cabin near theBlue Ridge Mountains of the eastern United States; it persisted through winter and lasted at least two years.[29]
Earwigs are mostly scavengers, but some are omnivorous or predatory.[7]: 739–740 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 holdingprey, and incopulation. The forceps tend to be more curved in males than in females.[30]
Species of the subordersArixeniina andHemimerina are generally considered epizoic, or living on the outside of otheranimals, mainly mammals. In theArixeniina, familyArixeniidae, species of the genusArixenia are normally found deep in the skin folds and gular pouch ofMalaysian hairless bulldog bats (Cheiromeles torquatus), apparently feeding on bats' body or glandular secretions. On the other hand, species in the genusXeniaria (still of the suborder Arixeniina) are believed to feed on theguano and possibly the guanophilous arthropods in the bat's roost, where it has been found.Hemimerina includesAraeomerus found in the nest oflong-tailed pouch rats (Beamys), andHemimerus which are found on giantCricetomys rats.[19][32]
Earwigs are generallynocturnal, 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.[30] During the summer they can be found around damp areas such as near sinks and in bathrooms. Earwigs tend to gather in shady cracks or openings or anywhere that they can remain concealed during daylight. Picnic tables, compost and waste bins, patios, lawn furniture, window frames, or anything with minute spaces (evenartichoke blossoms) can potentially harbour them.[33]
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.[34] European naturalists have observed bats preying upon earwigs.[34] Their primary insect predators are parasitic species ofTachinidae, or tachinid flies, whose larvae areendoparasites. One species of tachinid fly,Triarthria setipennis, has been demonstrated to be successful as a biological control of earwigs for almost a century.[35][36] Another tachinid fly and parasite of earwigs,Ocytata pallipes, has shown promise as a biological control agent as well.[37] The common predatory wasp, theyellow jacket (Vespula maculifrons), preys upon earwigs when abundant.[38] A small species of roundworm,Mermis nigrescens, is known to occasionally parasitize earwigs that have consumed roundworm eggs with plant matter.[39] At least 26 species of parasitic fungus from the orderLaboulbeniales have been found on earwigs.[40] The eggs and nymphs are also cannibalized by other earwigs.[41] A species of tyroglyphoid mite,Histiostoma polypori (Histiostomatidae,Astigmata), are observed on common earwigs, sometimes in great densities;[42] however, this mite feeds on earwig cadavers and not its live earwig transportation.[43]Hippolyte Lucas observed scarlet acarine mites on European earwigs.[44]
The fossil record of the Dermaptera starts in theLate Triassic toEarly Jurassic period about208 million years ago in England and Australia, and comprises about 70 specimens in the extinct suborderArchidermaptera. Some of the traits believed byneontologists to belong to modern earwigs are not found in the earliest fossils, but adults had five-segmentedtarsi (the final segment of the leg), well developedovipositors, veined tegmina (forewings) and long segmentedcerci; in fact the pincers would not have been curled or used as they are now.[14] The theorized stem group of the Dermaptera are theProtelytroptera, which are similar to modernBlattodea (cockroaches) with shell-like forewings and the large, unequal anal fan, are known from thePermian of North America, Europe and Australia. No fossils from the Triassic — during which Dermaptera would have evolved from Protelytroptera — have been found.[47] Amongst the most frequently suggested order of insects to be the closest relatives of Dermaptera isNotoptera, theorized by Giles in 1963. However, other arguments have been made by other authors linking them toPhasmatodea,Embioptera,Plecoptera, andDictyoptera.[11] A 2012mitochondrial DNA study suggested that this order is the sister to stoneflies of the orderPlecoptera.[48] A 2018 phylogenetic analysis found that their closest living relatives were angel insects of the orderZoraptera, with very high support.[49]
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.[50] Species in Hemimeridae were at one time in their own order, Diploglassata, Dermodermaptera, orHemimerina. Like most other epizoic species, there is no fossil record, but they are probably no older thanlate Tertiary.[14]
Some evidence of early evolutionary history is the structure of the antennal heart, a separatecirculatory organ consisting of twoampullae, or vesicles,[51] that are attached to the frontal cuticle near the bases of theantennae.[52] These features have not been found in other insects. An independent organ exists for each antenna, consisting of anampulla, 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.[53]
Head:Prognathous.Antennae are segmented. Biting-typemouthparts.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, veinlesstegmina. Hindwings aremembranous and semicircular withveins radiating outwards.
Abdomen:Cerci are unsegmented and resembleforceps. Theovipositor in females is reduced or absent.
The overwhelming majority of earwig species are in the former suborder Forficulina, grouped into nine families of 180 genera,[47] includingForficula 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 firstepizoic species of earwig was discovered by aLondontaxidermist on the body of aMalaysian hairless bulldog bat in 1909, then described byKarl Jordan. By the 1950s, the two suborders Arixeniina and Hemimerina had been added to Dermaptera.[19] These were subsequently demoted to familyArixeniidae and superfamily Hemimeroidea (with sole familyHemimeridae), respectively.[55] They are now grouped together with the former Forficulina in the new suborderNeodermaptera.[55]
Arixeniidae represents two genera,Arixenia andXeniaria, with a total of five species in them. As with Hemimeridae, they are blind and wingless, with filiform segmented cerci. Hemimeridae areviviparousectoparasites, preferring the fur of African rodents in eitherCricetomys orBeamys genera.[50] Hemimerina also has two genera,Hemimerus andAraeomerus, with a total of 11 species.[50]
Dermaptera is relatively small compared to the other orders ofInsecta, with only about 2,000 species, 3 suborders and 15 families, including the extinct subordersArchidermaptera and Eodermaptera with their extinct familiesProtodiplatyidae, Dermapteridae,Semenoviolidae, andTuranodermatidae. Thephylogeny of the Dermaptera is still debated. Theextant 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 wasparaphyletic through the exclusion of Hemimerina and Arixeniina which should instead be nested within the Forficulina.[47][56] Thus, these former suborders were eliminated in the most recent higher classification.
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.[57] Earwigs have been rarely known to crawl into the ears of humans,[58] and they do not lay eggs inside the human body or human brain as is often claimed.[59][60]
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 asaphids, though it would take a large population to do considerable damage. Thecommon 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,[61] andcorn crops in Germany, and in the south of France, earwigs have been observed feeding onpeaches andapricots. The earwigs attacked mature plants and made cup-shaped bite marks3–11 mm (1⁄8–7⁄16 in) in diameter.[62]
One of the primary characters of James Joyce's experimental novelFinnegans Wake is referred to by the initials "HCE," which primarily stand for "Humphrey Chimpden Earwicker," a reference to earwigs. Earwig imagery is found throughout the book, and also occurs in the author'sUlysses in the Laestrygonians chapter.[63]
Oscar Cook wrote the short story (appearing inSwitch On The Light, April, 1931;A Century Of Creepy Stories 1934;Pan Horror 2, 1960) "Boomerang", which was later adapted byRod Serling for theNight Gallery TV-series episode, "The Caterpillar".[64] It tells the tale of the use of an earwig as a murder instrument applied by a man obsessed with the wife of an associate.
Thomas Hood discusses the myth of earwigs finding shelter in the human ear in the poem "Love Lane" by saying the following:"'Tis vain to talk of hopes and fears, / And hope the least reply to win, / From any maid that stops her ears / In dread of earwigs creeping in!"[65]
In some parts of rural England the earwig is called "battle-twig", which is present inAlfred, Lord Tennyson's poemThe Spinster's Sweet-Arts:"'Twur as bad as battle-twig 'ere i' my oan blue chamber to me."[66]
In some regions of Japan, earwigs are called "Chinpo-Basami" or "Chinpo-Kiri", which means "penis cutter". Kenta Takada, a Japanese cultural entomologist, has inferred that these names may be derived from the fact that earwigs were seen around old Japanese-style toilets.[67]
InRoald Dahl's children's bookGeorge's Marvellous Medicine, George's Grandma encourages him to eat unwashed celery with beetles and earwigs still on them."'A big fat earwig is very tasty,' Grandma said, licking her lips. 'But you've got to be very quick, my dear, when you put one of those in your mouth. It has a pair of sharp nippers on its back end and if it grabs your tongue with those, it never lets go. So you've got to bite the earwig first, chop chop, before it bites you.'"[68]
^Friedrichsen, G W S; Robert W Burchfield (31 December 1966). Onions CT (ed.).The Oxford Dictionary of English Etymology (1996 ed.). United Kingdom, Oxford University: Oxford University Press. pp. earwig.ISBN978-0-19-861112-7.
^Marshall, Stephan A. (June 2006). "4".Insects: Their Natural History and Diversity: With a Photographic Guide to Insects of Eastern North America. Buffalo, NY; Richmond Hill, Ontario: Firefly Books. pp. 63–64.ISBN978-1-55297-900-6.
^abCranshaw, W.S. (January 2007)."European Earwigs".5.533. Colorado State University.Archived from the original on 27 July 2009. Retrieved25 June 2009.
^abcGrimaldi, David; Michael Engel (May 2005)."7".Evolution of the Insects. Cambridge Evolution Ser. (1 ed.). Cambridge University: Cambridge University Press. pp. 217–222.ISBN978-0-521-82149-0.Archived from the original on 9 June 2021. Retrieved16 November 2009.
^Carpenter, George Herbert (1899)."4".Insects: their structure & life. London: J. M. & Co. pp. 170–172.Archived from the original on 9 June 2021. Retrieved31 October 2020.
^abcT. Costa, James (May 2006)."3".The other insect societies. Foreword by Bert Hölldobler and commentary by Edward O. Wilson (1 ed.). Harvard University: Harvard University Press. pp. 53–54.ISBN978-0674021631.Archived from the original on 9 June 2021. Retrieved31 October 2020.
^Suzuki, S.; Kitamura M.; Matsubayashi, K. (2005). "Matriphagy in the hump earwig, Anechura harmandi (Dermaptera: Forficulidae), increases the survival rates of the offspring".Journal of Ethology.23 (2):211–213.doi:10.1007/s10164-005-0145-7.S2CID26557397.
^Cowan, Frank,The Project Gutenberg EBook of Curious Facts in the History of Insects; Including Spiders and Scorpions, 1865, EBook issue 15 December 2012,[1] (citingGentleman's Magazine, Aug. 1855, vol xxv, p. 376.) Accessed 1 September 2021
^Kevin Hathorne,Earwig invasion mystery, Pest Management Professional,[2] (specialist trade journal) accessed 1 September 2021
^abDrees, B.M.; Jackman, John (1999)."Earwig".Field Guide to Texas Insects. Houston: Gulf Publishing Company. p. 1. Archived fromthe original on 12 June 2010. Retrieved15 November 2009.
^Weiss, Michael J.; Garrick McDonald (1998). "European earwig,Forficula auriculari L. (Dermaptera: Forficulidae), as a predator of the redlegged earth mite,Halotydeus destructor (Tucker) (Acarina: Penthaleidae)".Australian Journal of Entomology.37 (2):183–185.doi:10.1111/j.1440-6055.1998.tb01569.x.
^Nakata, Satsuko; TC Maa (1974)."A review of the parasitic earwigs"(PDF).Pacific Insects.16:307–374.Archived(PDF) from the original on 21 August 2010. Retrieved28 November 2009.
^Grupp, Susan M.; Philip L. Nixon."The Bug Review-Earwigs". Extension Entomologist, Department of Natural Resources and Environmental Sciences, University of Illinois at Urbana-Champaign. p. 1.Archived from the original on 7 December 2009. Retrieved15 November 2009.
^abArnold, Richard A. "Earwigs."Endangered Wildlife and Plants of the World. Vol. 4. Eds. Anne Hildyard, Paul Thompson and Amy Prior. (Tarrytown, New York: Marshall Cavendish Corporation, 2001) 497.
^Dimick, R.E. and Mote, D.C. (1934) Progress report regarding the introduction in Oregon ofDigonocheata setipennis, a tachinid parasite of the European earwig.Journal of Economic Entomology 27, 863–865.
^Clausen, C.P. (1978) Dermaptera – Forficulidae – European Earwig. In: Clausen, C.P. (ed.)Introduced Parasites and Predators of Arthropod Pests and Weeds: A World Review, Handbook No. 480, United States Department of Agriculture, Washington, DC, pp. 15–18.
^Kuhlmann, Ulrich. (26 Aug 2009) "Ocytata pallipes (Fallén) (Dipt., Tachinidae), a potential agent for the biological control of the European earwig."Journal of Applied Entomology, Vol. 117, Issue 1–5, pp. 262–267.
^Kurczewski, Frank E. "Vespula maculifrons (Hymenoptera: Vespidae) Preying on the European Earwig Forficula auricularia."Journal of the New York Entomological Society, Vol. 76, No. 2 (Jun., 1968), pp. 84–86.
^Marshall, Judith A. "Dermaptera: the earwigs."Identifying British Insects and Arachnids: An Annotated Bibliography of Key Works. ed. Peter C. Barnard. (Cambridge: Cambridge University Press, 1999) 40.
^Shanor, Leland. "The Characteristics and Morphology of a New Genus of the Laboulbeniales on an Earwig."American Journal of Botany, Vol. 39, No. 7 (Jul. 1952), pp. 498–504.
^Behura, Basanta Kumar. "The Relationships of the Tyroglyphoid Mite, Histiostoma Polypori (Oud.) with the Earwig, Forficula Auricularia Linn."Journal of the New York Entomological Society, Vol. 64, (1956), pp. 85–94.
^Wirth, S. "Necromenic life style of Histiostoma polypori (Acari: Histiostomatidae)"Journal Experimental and Applied Acarology, Volume 49, Number 4 (December, 2009) pp. 317–327.
^Jarvis, Karl J.; Haas, Fabian; Whiting, Michael F. (2005). "Phylogeny of earwigs (Insecta: Dermaptera) based on molecular and morphological evidence: Reconsidering the classification of Dermaptera".Systematic Entomology.30 (3):442–453.Bibcode:2005SysEn..30..442J.doi:10.1111/j.1365-3113.2004.00276.x.S2CID85718043.
^abcFabian Haas.Dermaptera — Earwigs. Tree of Life web project.Archived from the original on 16 July 2007. Retrieved26 July 2007.
^Wan X, Kim MI, Kim MJ, Kim I (2012) Complete mitochondrial genome of the free-living earwig,Challia fletcheri (Dermaptera: Pygidicranidae) and phylogeny of Polyneoptera. PLoS One 7(8):e42056.
^abcEngel, Michael A.; Lim, Jong-Deock; Baek, Kwang-Seok; Martin, Larry D. (2002). "An Earwig from the Lower Cretaceous of Korea (Dermaptera: Forficulina)".Journal of the Kansas Entomological Society.75 (2):86–90.JSTOR25086049.
^Pass, Günther; Hans Agricola; Heiner Birkenbeil; Heinz Penzlin (August 1988). "Morphology of neurones associated with the antennal heart ofPeriplaneta americana (Blattodea, Insecta)".Cell and Tissue Research.253 (2):319–326.doi:10.1007/bf00222288.ISSN0302-766X.PMID3409288.S2CID24602483.
^Nation, James L. (28 November 2001)."11: Circulatory System".Insect physiology and biochemistry (1 ed.). CRC Press. p. 310.ISBN978-0-8493-1181-9.Archived from the original on 9 June 2021. Retrieved12 September 2020.
^Mikkelson, Barbara; David P. Mikkelson (1995)."Bugs in the Ear".Urban Legends Reference Pages. Snopes.com. p. 1.Archived from the original on 9 June 2021. Retrieved22 November 2009.
^Berenbaum, May R. (2009). "The Brain-Boring Earwig".The Earwig's Tail: A Modern Bestiary of Multi-Legged Legends. Cambridge, Mass.: Harvard University Press. pp. 10, 14.ISBN978-0-674-03540-9.
^Gordon, SC; Cormack, MR; Hackett, CA (September 1997). "Arthropod contamination of red raspberry (Rubus idaeus L.) harvested by machine in Scotland".Journal of Horticultural Science.72 (5):677–685.doi:10.1080/14620316.1997.11515559.
^Twinn, Cecil (1942).Insect Life in the Poetry and Drama of England: With Special Reference to Poetry (Thesis). University of Ottawa. pp. 241–242.OCLC877128347.
