Forficula auriculariaEuropean earwig

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Geographic Range

European earwigs are native to Europe, eastern Asia, and northern Africa. Today, they can be found on all continents except Antarctica. Their geographic range continues to expand, and they have been found on an island in the Pacific Ocean (Island of Guadalupe). (Jacobs, 2009; Pavon-Gozalo, et al., 2011)

Habitat

European earwigs are terrestrial organisms that live in mostly temperate climates. They are found in a very large geographic range and at elevations up to 2,824 m. During the day, they prefer places that are dark and moist to hide from predators. Their habitats include forests, agricultural, and suburban areas. During the mating season, females prefer a habitat abundant in rich soils as a place to burrow and deposit her eggs. (Pavon-Gozalo, et al., 2011; Weems and Skelley, 2007)

  • Range elevation
    2824 (high) m
    9265.09 (high) ft

Physical Description

European earwigs are brownish red in color and have elongated bodies that range from 12 to 15 mm long. They are equipped with 3 pairs of legs that are yellow to brown in color. European earwigs are well-known for the set of forceps, known as cerci, that protrude from the abdomen and are used for protection and in mating rituals. Forceps display sexual dimorphism, with those of the male being longer and more curved than those of the female. Forceps can also vary between males. Males with shorter and highly curved forceps are called brachylabic, while males with long, straighter forceps are called macrolabic. European earwigs have two antennae with 14 to 15 segments long that contain many important sense organs, as well as a fully developed set of wings. (Rantala, et al., 2006; Slifer, 2005; Suckling, et al., 2006)

  • Sexual Dimorphism
  • sexes shaped differently
  • Range length
    12 to 15 mm
    0.47 to 0.59 in

Development

Females lay fertilized eggs in a burrow dug into the soil. After about 70 days, the eggs hatch into first instar nymphs that remain in the burrow as the mother provides protection and food. When the young become second instar nymphs, they emerge above ground and find their own food. During the day however, they return to their burrow. Third and fourth instar nymphs live above ground where they develop into adults. Nymphs are similar to adults, but are lighter in color with smaller wings and antennae. As the nymphs progress from one instar to the next, they begin to darken in color, the wings grow, and the antennae gain more segments. Between each stage of development, the young molt by losing their outer cuticle. (Alston and Tebeau, 2011; Capinera, 2008; Jacobs, 2009)

Reproduction

European earwig mating rituals usually occur in September, after which mating pairs can usually be found underground in a burrow into the winter. Courtship rituals involving the forceps play a large role in the mating process. Males wave and bob the forceps in the air, stroking and grasping the female. However, the forceps are not used in the actual mating process. If the female accepts the courting male, the male twists his abdomen into position for mating and attaches to the female. During mating, females move around and feed with the male attached to her abdomen. Fertilization of eggs takes place inside the female. Sometimes during mating, another male comes along and uses his forceps to fight off the mating male and take his place with the mating female. Males and females have multiple mates. (Avery, et al., 2002; Walker and Fell, 2001)

European earwigs typically breed once yearly from September to January. Some females actually breed twice during this time frame. Eggs are fertilized internally inside the female and in late winter or early spring females lay 30 to 55 eggs. The offspring become independent two months after hatching and no longer require parental care. European earwigs reach sexual maturity at 3 months and are able to reproduce in the next breeding season. (Capinera, 2008; Jacobs, 2009; Pellitteri, 1999)

  • Breeding interval
    European earwigs usually breed once yearly, but some females breed twice during mating season.
  • Breeding season
    European earwigs breed from September to January.
  • Range eggs per season
    30 to 55
  • Average time to independence
    2 months
  • Average age at sexual or reproductive maturity (female)
    3 months
  • Average age at sexual or reproductive maturity (male)
    3 months

Female European earwigs hibernate about 5 to 8 mm underground with their eggs, guarding them and keeping them clean from fungi and other pathogens using their mouth. The males are usually driven from the burrow in late winter or early spring and the female proceeds to lay her fertilized eggs. Once the larvae hatch in about 70 days, mothers provide their young with food by regurgitation until they reach the second. (Kolliker, 2007; Staerkle and Kolliker, 2008; Weems and Skelley, 2007)

  • Parental Investment
  • female parental care
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female

Lifespan/Longevity

A typical European earwig lives 1 year in the wild. Male earwigs often die before females, when they are kicked out of the burrow during the winter months. (Avery, et al., 2002)

  • Average lifespan
    Status: wild
    1 years
  • Average lifespan
    Status: wild
    1 years

Behavior

European earwigs are nocturnal. They hide during the day in dark moist places, such as under rocks, potted plants, wood piles, in fruits, flowers and other similar places. At night, they emerge to hunt or scavenge for food. They are weak fliers and therefore move around mostly by crawling and human transportation. European earwigs can be considered both solitary and colonial. Female earwigs live alone during the mating season, but during the other months of the year earwigs tend to congregate in very large groups. ("Common European Earwig", 2012; Crumb, et al., 1941; Jacobs, 2009; Kolliker, 2007)

European earwigs are considered to be a sub-social species as they provide parental care for their young. When European earwigs feel threatened or their offspring are threatened by a predator, they use their forceps as a weapon by snapping them quickly together. ("Common European Earwig", 2012; Crumb, et al., 1941; Jacobs, 2009; Kolliker, 2007)

Home Range

There is little information on the home range of European earwigs. They are often found far from their point of origin due to human transfer from hiding in objects such as newspapers. ("Earwigs", 2011)

Communication and Perception

Adult European earwigs release a pheromone that attracts other European earwigs. Nymphs also release pheromones, which encourage mothers to provide care to their young. Forceps are also used as means of communication in mating and to show threatening behavior. (Farmer, 2010; Hehar, 1999; Slifer, 2005)

The segmented antennae of European earwigs contain many sense organs such as chemoreceptors that aid in sensing odors. These antennae also contain important tactile hairs which help the organism to get a sense of the surrounding environment. They also have compound eyes, enabling them to use sight as well to perceive their environment. (Farmer, 2010; Hehar, 1999; Slifer, 2005)

Food Habits

European earwigs are omnivorous organisms that are both scavengers and predators and feed using their chewing mouthparts. They feed on other organisms, both dead and alive, including aphids, maggots, mites, spiders, and protozoans. They also feed on both living and decaying plants, including lichens, algae, fruits and flowers. (Crumb, et al., 1941; Rammel, 1998)

  • Animal Foods
  • eggs
  • insects
  • Plant Foods
  • leaves
  • fruit
  • flowers
  • bryophytes
  • lichens
  • algae

Predation

European earwigs are preyed upon by several species of tachinid flies (Diptera), as well as certain beetles (Coleoptera). These include ground beetles like Pterostichus vulgaris, P. algidus, Carabus nemoralis, and Calosoma tepidum, as well as flightless tiger beetles (Omus dejeanii). Other predators include toads (Anura), snakes (Serpentes), and certain birds (Aves) like Chinese monal pheasants (Lophophorus ihuysii). European earwigs have several different defense mechanisms used to avoiding predation. These include using their forceps as a weapon and using glands found in the abdomen to secrete chemicals that act as a repellent to predators. (Crumb, et al., 1941; Eisner, 1960)

  • Known Predators
    • ground beetles (Pterostichus vulgaris)
    • ground beetles (Pterotichus algidus)
    • ground beetles (Carabus nemoralis)
    • ground beetles (Calosoma tepidum)
    • flightless tiger beetles (Omus dejeanii)
    • toads (Anura)
    • snakes (Serpentes)
    • birds (Aves)
    • Chinese monal pheasants (Lophophorus ihuysii)

Ecosystem Roles

European earwigs are common hosts to several different parasitic organisms including certain tachinid flies (Thriarthria setipennis and Ocytata pallipes) and nematodes (Mermis nigresens>). They also serve as predators of other types of insects such as aphids (Aphidoidea) and some protozoa. European earwigs are also important scavengers in the ecosystem, feeding on almost anything that is edible. (Crumb, et al., 1941; Suckling, et al., 2006; Zack, et al., 2011)

Commensal/Parasitic Species
  • nematodes (Mermis nigresens)
  • tachnid flies (Thriarthria setipennis)
  • tachnid flies (Ocytata pallipes)

Economic Importance for Humans: Positive

Aphids, a staple in European earwigs' diet, can cause great destruction to apple and pear orchards. European earwigs can help to control the population of aphids, thereby decreasing the amount of pest destruction to the crops. (Suckling, et al., 2006)

  • Positive Impacts
  • controls pest population

Economic Importance for Humans: Negative

Since European earwigs tend to hide in dark, moist places such as newspapers or inside fruits, they are commonly carried into homes. European earwigs are essentially harmless to humans, but their unpleasant odor and appearance make them unwanted guests in the home. They can also cause damage to fruits and other crops as they feed on them. They are not as nearly destructive as aphids or other pests, but their feeding can still cause considerable damage to crops. (Crumb, et al., 1941; Weems and Skelley, 2007)

  • Negative Impacts
  • crop pest
  • household pest

Conservation Status

European earwigs are not endangered or threatened.

Other Comments

A common misconception about earwigs based on their name is that they crawl into the ears of humans. This is actually a myth, and there are few known cases of earwigs actually crawling into the ears of people. The name earwig is actually derived from the fact that the hind wings of the organism resemble the shape of an ear. ("Common European Earwig", 2012; Crumb, et al., 1941; Jacobs, 2009; Kolliker, 2007)

Contributors

Morgan Vincent (author), University of Michigan-Ann Arbor, Catherine Kent (editor), Special Projects.

Glossary

Australian

Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

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Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

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Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

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Neotropical

living in the southern part of the New World. In other words, Central and South America.

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Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

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agricultural

living in landscapes dominated by human agriculture.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

colonial

used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.

cosmopolitan

having a worldwide distribution. Found on all continents (except maybe Antarctica) and in all biogeographic provinces; or in all the major oceans (Atlantic, Indian, and Pacific.

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

female parental care

parental care is carried out by females

fertilization

union of egg and spermatozoan

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

internal fertilization

fertilization takes place within the female's body

introduced

referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.

metamorphosis

A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

omnivore

an animal that mainly eats all kinds of things, including plants and animals

oriental

found in the oriental region of the world. In other words, India and southeast Asia.

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oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

pheromones

chemicals released into air or water that are detected by and responded to by other animals of the same species

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

suburban

living in residential areas on the outskirts of large cities or towns.

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

visual

uses sight to communicate

References

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Capinera, J. 2008. Encyclopedia of Entomology. Gainesville, FL: Springer Science+Business Media B.V.. Accessed March 21, 2012 at http://books.google.com/books?id=i9ITMiiohVQC&pg=PA1368&lpg=PA1368&dq=lifespan+of+Forficula+auricularia&source=bl&ots=VWBlPwgNRQ&sig=-GkAGkMHMrCAZC_xKY8uNtetSM4&hl=en&sa=X&ei=lIZqT_rmCsbjsQLl2fH1BQ&ved=0CC8Q6AEwAzgK#v=onepage&q=lifespan%20of%20Forficula%20auricularia&f=false.

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Pavon-Gozalo, P., B. Mila, P. Aleixandre, J. Calderon, A. Zaldivar-Riveron, J. Hernandez-Montoya, M. Garcia-Paris. 2011. INVASION OF TWO WIDELY SEPARATED AREAS OF MEXICO BY FORFICULA AURICULARIA (DERMAPTERA: FORFICULIDAE). Florida Entomologist, 94/4: 1088-1090. Accessed February 23, 2012 at http://www.bioone.org/doi/pdf/10.1653/024.094.0457.

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Rantala, M., D. Roff, L. Rantala. 2006. Forceps size and immune function in the earwig Forficula auricularia L.. Biological Journal of the Linnean Society, 90/3: 509-516. Accessed February 02, 2012 at http://dl2af5jf3e.search.serialssolutions.com.proxy.lib.umich.edu/?sid=CSA:objectsclust-env-set-c&pid=%3CAN%3E301%2D0002489752%3C%2FAN%3E%26%3CPB%3EBlackwell%20Publishing%20Ltd%2E%2C%209600%20Garsington%20Road%3C%2FPB%3E%26%3CPY%3E2007%3C%2FPY%3E%26%3CAU%3ERANTALA%2C%20MARKUS%20J%3B%20ROFF%2C%20DEREK%20A%3B%20RANTALA%2C%20LIISA%20M%3C%2FAU%3E&id=doi%3A10%2E1111%2Fj%2E1095%2D8312%2E2007%2E00741%2Ex&issn=0024%2D4066&volume=90&issue=3&spage=509&epage=516&date=2007%2D03&genre=article&aulast=RANTALA&auinit=MARKUSJ&title=Biological%20Journal%20of%20the%20Linnean%20Society&atitle=Forceps%20size%20and%20immune%20function%20in%20the%20earwig%20Forficula%20auricularia%20L%2E.

Slifer, E. 2005. Sense Organs on the Antenna1 Flagella of Earwigs (Dermaptera) with Special Reference to those of Forficula auricularia. Journal of Morphology, 122/1: 63-80. Accessed February 23, 2012 at http://onlinelibrary.wiley.com.proxy.lib.umich.edu/doi/10.1002/jmor.1051220105/pdf.

Staerkle, M., M. Kolliker. 2008. Maternal Food Regurgitation to Nymphs in Earwigs (Forficula auricularia). Ethology, 114/9: 844-850. Accessed March 21, 2012 at http://onlinelibrary.wiley.com.proxy.lib.umich.edu/doi/10.1111/j.1439-0310.2008.01526.x/pdf.

Suckling, D., G. Burnip, J. Hackett, J. Daly. 2006. Frass sampling and baiting indicate European earwig (Forficula auricularia) foraging in orchards. Journal of Applied Entomology, 130/5: 263-267. Accessed February 23, 2012 at http://onlinelibrary.wiley.com.proxy.lib.umich.edu/doi/10.1111/j.1439-0418.2006.01064.x/pdf.

Walker, K., R. Fell. 2001. Courtship Roles of Male and Female European Earwigs, Forficula auricularia L. (Dermaptera: Forficulidae), and Sexual Use of Forceps. Journal of Insect Behavior, 14/1: 1-17. Accessed March 19, 2012 at http://www.springerlink.com.proxy.lib.umich.edu/content/u6u1013315x85883/fulltext.pdf.

Weems, H., P. Skelley. 2007. "European Earwig, Forficula auricularia Linnaeus (Insecta: Dermaptera: Forficulidae)" (On-line). Accessed February 02, 2012 at http://edis.ifas.ufl.edu/pdffiles/IN/IN15900.pdf.

Zack, R., D. Strenge, P. Landolt, L. Chris. 2011. EUROPEAN EARWIG, FORFICULA AURICULARIA L. (DERMAPTERA: FORFICULIDAE), AT THE HANFORD REACH NATIONAL MONUMENT, WASHINGTON STATE. Western North American Naturalist, 70/4: 441-445. Accessed February 02, 2012 at http://www.bioone.org.proxy.lib.umich.edu/doi/pdf/10.3398/064.070.0403.