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.
Known Predators:
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.
Range length: 12 to 15 mm.
Sexual Dimorphism: sexes shaped differently
Other Physical Features: ectothermic ; bilateral symmetry
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.
Average lifespan
Status: wild: 1 years.
Average lifespan
Status: wild: 1 years.
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.
Range elevation: 2824 (high) m.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: forest
Other Habitat Features: suburban ; agricultural
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.
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.
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.
Communication Channels: chemical
Other Communication Modes: pheromones
Perception Channels: visual ; tactile ; chemical
European earwigs are not endangered or threatened.
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
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.
Development - Life Cycle: metamorphosis
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.
Negative Impacts: crop pest; household pest
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.
Positive Impacts: controls pest population
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.
Commensal/Parasitic Species:
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.
Animal Foods: eggs; insects
Plant Foods: leaves; fruit; flowers; bryophytes; lichens; algae
Primary Diet: omnivore
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).
Biogeographic Regions: nearctic (Introduced ); palearctic (Native ); oriental (Native ); ethiopian (Introduced ); neotropical (Introduced ); australian (Introduced )
Other Geographic Terms: cosmopolitan
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.
Mating System: polygynandrous (promiscuous)
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.
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.
Key Reproductive Features: seasonal breeding ; sexual ; fertilization (Internal ); oviparous
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.
Parental Investment: female parental care ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female)
Forficula auricularia, the common earwig or European earwig, is an omnivorous insect in the family Forficulidae. The European earwig survives in a variety of environments and is a common household insect in North America. The name earwig comes from the appearance of the hindwings, which are unique and distinctive among insects, and resemble a human ear when unfolded; the species name of the common earwig, auricularia, is a specific reference to this feature.[1][2] They are considered a household pest because of their tendency to invade crevices in homes and consume pantry foods,[3] and may act either as a pest or as a beneficial species depending on the circumstances (see below).[4][5]
Forficula auricularia is reddish-brown in color, with a flattened and elongate body, and slender, beaded antennae. An obvious feature of earwigs is the pair of 'pincers' or forceps at the tip of the flexible abdomen. Both sexes have these pincers; in males they are large and very curved, whereas in females they are straight. Nymphs are similar to adults in appearance, but their wings are either absent or small[6]
Forficula auricularia has an elongated flattened brownish-colored body,[7] with a shield-shaped pronotum,[8] two pairs of wings and a pair of forcep-like cerci.[9] They are about 12–15 mm long. The second tarsal segment is lobed, extending distally below the third tarsal segment.[10] The antenna consists of 11–14 segments, and the mouth parts are of the chewing type.[7]
Adult males are polymorphic in body weight and head width, as well as cercus length and width.[11] The male forceps are very robust and broadened basally with crenulate teeth.[12] The female forceps are about 3 mm long, and are less robust and straighter. The cerci are used during mating, feeding, and self-defense. Females also have tegmina of about 2 mm in length. Third instar or older nymphs that have lost one branch of cerci are capable of regenerating it in form of a straight structure. Males with asymmetrical forceps are called gynandromorphs or hermaphrodites because they resemble females.[13]
Native to Europe, western Asia and probably North Africa,[14][15] Forficula auricularia was introduced to North America in the early twentieth century and is currently spread throughout much of the continent.[12] It was accidentally introducted into New Zealand by Early European settlers.[16] In North America, European earwigs comprise two sibling species, which are reproductively isolated.[17] Populations in cold continental climates mostly have one clutch per year, forming species A,[18] whereas those in warmer climates have two clutches per year, forming species B.[17][19] European earwigs are most commonly found in temperate climates, since they were originally discovered in the Palearctic region, and are most active when the daily temperature has minimal fluctuation.[3][20]
European earwigs spend the daytime in cool, dark, inaccessible places such as flowers, fruits, and wood crevices.[9][14][21] Active primarily at night, they seek out food ranging from plant matter to small insects. Though they are omnivorous, they are considered as scavengers rather than predators.[3] Often they consume plant matter, though they have also been known to feed on aphids, spiders, insect eggs, and dead plants and insects, among other things.[20] Their favorite plants include the common crucifer Sisymbrium officinale, the white clover Trifolium repens, and the dahlia Dahlia variabilis.[22] They also like to feed on molasses, as well as on nonvascular plants, lichens and algae.[14] They prefer meat or sugar to natural plant material even though plants are a major natural food source.[23] European earwigs prefer aphids to plant material such as leaves and fruit slices of apple, cherry and pear.[24] Adults eat more insects than do nymphs.[14]
Although F. auricularia have well-developed wings, they are fairly weak and are rarely, if ever, used.[21] Instead, as their main form of transportation, earwigs are carried from one place to another on clothing or commercial products like lumber, ornamental shrubs and even newspaper bundles.[12][25]
A male finds prospective mates by olfaction. He then slips his cerci under the tip of the female's abdomen so that his and her ventral abdominal surfaces are in contact with each other, while both face in opposite directions. If not disturbed, pairs can stay in this mating position for many hours.[9][13] Matings occurred frequently among clustered individuals particularly in locations that allow both partners to cling to a surface.[9] Under laboratory conditions, the mating season peaked during August and September, and a single mating event enabled females to lay fertilized eggs.[13]
European earwig nymphs look very similar to their adult counterparts except that they are a lighter color.[12] The young go through four nymphal stages and do not leave the nest until after the first moult.[3]
European earwigs overwinter about 5 mm below the surface of the ground. The female earwig lays a clutch of about 50 eggs in an underground nest in the autumn. She enters a dormant state and stays in the nest with the eggs. The female cares for her young by shifting the eggs about and cleaning them to avoid fungal growth. In the spring, she spreads them out into a single layer and the young emerge from the eggs.[20] She guards them until they reach maturity after about one month. It is possible for the female to lay a second brood in one season and by the end of August all of the young reach maturity.[3]
European earwigs survive well in cool, moist habitats and have an optimum mean growth temperature of 24 °C (75 °F).[14] Their daily abundance in a given year has been linked to factors such as temperature, wind velocity and the prevalence of easterly winds.[26] The development of European earwigs also depends on temperature.[13][14] Thus, the occurrence of European earwigs can be predicted based on weather parameters.[27] Hibernating adults can tolerate cool temperatures, but their survival is reduced in poorly drained soils such as clay.[14] To avoid excessive moisture, they seek the southern side of well-drained slopes. Sometimes they also occupy the hollow stems of flowers where the soil is poorly drained.[13][28] Their eggs are capable of resisting damage from cold and heat.[29]
Forficula auricularia has been known to cause significant damage to crops, flowers, and fruit orchards when at high population levels. Some of the commercially valuable vegetables it feeds upon include cabbage, cauliflower, chard, celery, lettuce, potato, beet, and cucumber among others. Earwigs readily consume corn (maize) silk and can damage the crop. Among fruits, they have been found to damage apple and pear orchards. They damage young plum and peach trees in early spring, when other food is scarce, by devouring blossoms and leaves at night. It is not uncommon to find them wedged among petals of fresh cut carnations, roses, dahlia and zinnia.[20]
In addition to all of the agricultural problems caused, humans are not very fond of F. auricularia because of its foul odor and annoying propensity to aggregate together in or near human dwellings.[20]
Control of F. auricularia has been attempted using some of its natural enemies, including the parasitoid fly Bigonicheta spinipenni, the fungi Erynia forficulae and Metarhizium anisopliae, as well as many species of birds.[20] The tachinid flies Triarthria setipennis (Fallen) and Ocytata pallipes have been introduced in North America to control F. auricularia in the 1920s.[30]
Insecticides have also been successfully implemented, although commercial products are rarely targeted specifically towards earwigs. Multipurpose insecticides for control of earwigs, grasshoppers, sowbugs and other insects are more common.[20] Diazinon, an organophosphate insecticide, has been known to continue killing F. auricularia up to 17 days after initial spraying.[31]
Humans have, however, found beneficial uses of F. auricularia in the pest management of other insects. The European earwig is a natural predator of a number of other agricultural pests, including the pear psyllid and several aphid species, and in this regard has been used to control outbreaks of such organisms.[5] Damage to crops by F. auricularia is limited as long as there are high population levels of their insect prey.[4]
Forficula auricularia, the common earwig or European earwig, is an omnivorous insect in the family Forficulidae. The European earwig survives in a variety of environments and is a common household insect in North America. The name earwig comes from the appearance of the hindwings, which are unique and distinctive among insects, and resemble a human ear when unfolded; the species name of the common earwig, auricularia, is a specific reference to this feature. They are considered a household pest because of their tendency to invade crevices in homes and consume pantry foods, and may act either as a pest or as a beneficial species depending on the circumstances (see below).
Forficula auricularia is reddish-brown in color, with a flattened and elongate body, and slender, beaded antennae. An obvious feature of earwigs is the pair of 'pincers' or forceps at the tip of the flexible abdomen. Both sexes have these pincers; in males they are large and very curved, whereas in females they are straight. Nymphs are similar to adults in appearance, but their wings are either absent or small
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