Geographic Range
Ring-legged earwigs (
Euborellia annulipes
) are native to Europe, but currently have a near-global distribution due to unintentional
human introductions. Ring-legged earwigs were first reported in the United States
in 1884, and have since invaded large parts of the U.S. and Canada. They are also
present in Central and South America, as far south as Brazil. Ring-legged earwigs
spread from their native areas to parts of Asia, including South Korea, India, and
northeast Africa. They have also been introduced to New Zealand and other islands
in the Pacific Ocean and Caribbean sea.
- Biogeographic Regions
- nearctic
- palearctic
- oriental
- ethiopian
- neotropical
- oceanic islands
- Other Geographic Terms
- holarctic
Habitat
Ring-legged earwigs are terrestrial and capable of surviving in a variety of biomes
and at a wide range of elevations, from 0 to 1600 m above sea level. In colder climates,
ring-legged earwigs live mainly in consistently warm areas, such as greenhouses and
other human-made structures. Ring-legged earwigs are often found where food is sufficient,
including grain stores and agricultural fields.
- Habitat Regions
- temperate
- tropical
- terrestrial
- Terrestrial Biomes
- taiga
- desert or dune
- savanna or grassland
- forest
- rainforest
- Other Habitat Features
- urban
- suburban
- agricultural
Physical Description
Adult ring-legged earwigs are dark brown and 12 to 16 mm long. They have pale yellow
legs with distinctive dark brown rings encircling their most proximal leg segments.
Some individuals also have bands on their distal leg segments. Adults are wingless
and have long, filiform antennae, each with 16 segments and pale bands near the tips.
Ring-legged earwigs exhibit sexual dimorphism. In addition to being slightly smaller
than females, males have cerci (terminal defense and sensory appendages on their abdomens)
that are C-shaped, compared to the long, straight cerci of females. Additionally,
female ring-legged earwigs have only eight abdominal segments, whereas males have
ten.
Ring-legged earwig nymphs look physically similar to adults, as they are wingless
and have 8 or 10 abdominal segments, depending on sex. Nymphs go through 5 to 6 instars
before developing into adults. They are mostly dark brown, with the exception of the
pronotum of their thoraces, which is paler than the rest of their thoraces. Nymphs
have paler legs than adults, but both nymphs and adults have distinctive bands on
the proximal segments of their legs. For both males and females, nymphs typically
have cerci that are straighter and shorter than the cerci of adults. All instars are
similar in appearance, although they differ in overall length and number of antenna
segments. For example, first instar nymphs are about 3 to 5 mm long with 8 antenna
segments whereas sixth instar nymphs are about 10 to 13 mm long with 14 to 17 antennal
segments.
When ring-legged earwig females initially lay their eggs, the eggs are white, spherical,
and about 0.75 mm long. However, they become longer, browner, and more elliptical
as they get closer to hatching.
- Other Physical Features
- ectothermic
- bilateral symmetry
- Sexual Dimorphism
- female larger
- sexes shaped differently
Development
Ring-legged earwigs are relatively short-lived insects that go through incomplete
metamorphosis. This means that nymphs hatch from eggs and progress through several
molts, or instars, with later instars being more similar to adults in appearance and
size. It takes 5 to 6 instars before they become reproductive adults. Adults can live
for several months, and may undergo diapause depending on environmental conditions.
- Development - Life Cycle
- metamorphosis
- diapause
Reproduction
Ring-legged earwigs are polygynandrous, meaning both sexes have multiple mates throughout
their life. For females, only one mating event will result in a clutch of eggs, but
females mate with multiple males before that time. Light can disturb normal mating
behavior, and thus most mating occurs in dark places. Males and females only begin
copulation after successful communication via touch and visual cues, and this process
can take up to an hour in its entirety. After an intricate process of touching antennae
and moving from front-to-back to the meeting of dorsal cerci, females slowly cease
moving. Females then raise their cerci and allow males to begin copulation. The actual
process of sperm delivery takes less than ten minutes.
- Mating System
- polygynandrous (promiscuous)
Ring-legged earwigs breed in warmer months, typically between March and September.
Individuals mate multiple times over a single breeding season. Females lay around
50 eggs in one clutch after several weeks of gestation. After hatching, nymphs progress
through 5 to 6 instars before they reach adulthood, a process that takes around 2
months to complete. Once ring-legged earwigs reach adulthood, they will either mate
in the second half of the same breeding season or overwinter and mate in the beginning
of the following breeding season.
- Key Reproductive Features
- seasonal breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- fertilization
- oviparous
After mating, both earwig parents excavate burrows in the soil, where females deposit
their eggs. After this point, females chase males away from their burrows and provide
all further parental care. Female ring-legged earwigs clean, incubate, and protect
their eggs while they develop. To defend their eggs, females will use their forceps
to attack potential predators or, if necessary, they will pick up individual eggs
in their mandibles and move their clutch of eggs to safety. However, if the effort
to care for eggs is too great, females will either abandon them or eat them. Females
provide further protection for hatchlings through their first instar. Ring-legged
earwigs are fully independent upon their second instar.
- Parental Investment
- female parental care
-
pre-fertilization
-
protecting
- male
- female
-
protecting
-
pre-hatching/birth
-
protecting
- female
-
protecting
-
pre-independence
-
provisioning
- female
-
protecting
- female
-
provisioning
Lifespan/Longevity
Behavior
Ring-legged earwigs are nocturnal and prefer to stay under cover or leaf litter or
objects on soil. Otherwise, little is known of their behavior.
Home Range
Home range sizes are not reported in the literature.
Communication and Perception
Little is known of communication and perception modalities in ring-legged earwigs, although they are likely to use chemical (scent) and tactile cues to navigate the environment.
Food Habits
Ring-legged earwigs are considered omnivorous, eating both plants and animals. Predation
on a wide variety of small insects and pillbugs (
Armadillidiidae
) has been reported, including insects that are known agricultural and garden pests,
such as
caterpillars
,
leafhoppers
, and
beetle larvae
. This predation, as well as their competition with
fire ants
, may make them beneficial insects to have in gardens. They do, however, also eat
small amounts of plant material, including sometimes leafy vegetables and the roots
of radish, potato, or peanuts. However, the majority of plant material they eat seems
to be detritus and they do not seem to cause substantial damage to garden plants or
crops.
- Primary Diet
- omnivore
- Animal Foods
- insects
- terrestrial non-insect arthropods
- Plant Foods
- leaves
- roots and tubers
Predation
A wide variety of predators has been described for earwigs generally, but the specific predators of ring-legged earwigs have not been described. It is likely that they are eaten by any insect predator that is large enough to consume them, including lizards , toads and frogs , birds , spiders , hornets , and centipedes .
Ecosystem Roles
Ring-legged earwigs likely act as important predators of small insects, both in their
native and introduced ranges.
Economic Importance for Humans: Positive
There are no reported positive impacts of ring-legged earwigs for humans, although
some research suggests they compete directly with fire ants (
Solenopsis invicta
) for insect prey, which suggests ring-legged earwigs may be helpful in reducing fire
ant populations and reducing populations of small insects, which may be agricultural
pests.
- Positive Impacts
- controls pest population
Economic Importance for Humans: Negative
Ring-legged earwigs are moderately important crop pests in that they are capable of
causing some damage. Since they are able to dig, they can eat parts of crops that
are both below and above the ground, such as leaves, tubers, roots, and fruits. Additionally,
their frass may sometimes cause leafy vegetables to be thrown out, which can be an
economic loss as well (Capinera, 2021).
More specifically, ring-legged earwigs are quite often pests of stored foods as well.
Potatoes of the Irish and Sweet varieties in storage have been preyed on, as well
as flour and corn products in mills and stores across the United States. They may
even cause damage to dry food kept for livestock, and organic materials in the early
stages of the brewing process. Their ability to eat all parts of a plant above and
below ground means that they are also problematic in nurseries, greenhouses, and other
growing facilities. Ring-legged earwigs are even capable of vectoring disease-causing
endoparasites of some bird species in Hawaii (Bharadwaj, 1966).
- Negative Impacts
- crop pest
- causes or carries domestic animal disease
Conservation Status
There is no special conservation status for ring-legged earwigs as they are common where they are found.
Additional Links
Contributors
Amy Bagby (author), Colorado State University, Galen Burrell (author), Special Projects.
- 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.
- introduced
-
referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.
- Palearctic
-
living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- oriental
-
found in the oriental region of the world. In other words, India and southeast Asia.
- introduced
-
referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.
- Ethiopian
-
living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.
- introduced
-
referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.
- Neotropical
-
living in the southern part of the New World. In other words, Central and South America.
- introduced
-
referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.
- oceanic islands
-
islands that are not part of continental shelf areas, they are not, and have never been, connected to a continental land mass, most typically these are volcanic islands.
- introduced
-
referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.
- holarctic
-
a distribution that more or less circles the Arctic, so occurring in both the Nearctic and Palearctic biogeographic regions.
Found in northern North America and northern Europe or Asia.
- 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).
- tropical
-
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
- terrestrial
-
Living on the ground.
- taiga
-
Coniferous or boreal forest, located in a band across northern North America, Europe, and Asia. This terrestrial biome also occurs at high elevations. Long, cold winters and short, wet summers. Few species of trees are present; these are primarily conifers that grow in dense stands with little undergrowth. Some deciduous trees also may be present.
- desert or dunes
-
in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.
- tropical savanna and grassland
-
A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.
- savanna
-
A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.
- temperate grassland
-
A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.
- forest
-
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
- rainforest
-
rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.
- urban
-
living in cities and large towns, landscapes dominated by human structures and activity.
- suburban
-
living in residential areas on the outskirts of large cities or towns.
- agricultural
-
living in landscapes dominated by human agriculture.
- 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.
- diapause
-
a period of time when growth or development is suspended in insects and other invertebrates, it can usually only be ended the appropriate environmental stimulus.
- 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
- sexual
-
reproduction that includes combining the genetic contribution of two individuals, a male and a female
- fertilization
-
union of egg and spermatozoan
- internal fertilization
-
fertilization takes place within the female's body
- oviparous
-
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
- female parental care
-
parental care is carried out by females
- nocturnal
-
active during the night
- motile
-
having the capacity to move from one place to another.
- sedentary
-
remains in the same area
- causes or carries domestic animal disease
-
either directly causes, or indirectly transmits, a disease to a domestic animal
- omnivore
-
an animal that mainly eats all kinds of things, including plants and animals
- ectothermic
-
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
- 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.
References
Bharadwaj, R. 1966. Observations of the Bionomics of Euborellia annulipes (Dermaptera: Labiduridae). Annals of the Entomological Society of America , 59:3: 441-450.
CABI, 2021. "Euborellia annulipes (ring-legged earwig)" (On-line). Invasive Species Compendium. Accessed January 03, 2021 at https://www.cabi.org/isc/datasheet/83272 .
Capinera, J. 2020. Handbook of Vegetable Pests (Second Edition) . San Diego, California: Academic Press. Accessed January 04, 2021 at https://www.sciencedirect.com/science/article/pii/B9780128144886000066 .
Capinera, J. 2021. "Common name: ringlegged earwig; Scientific name: Euborellia annulipes (Lucas) (Insecta: Dermaptera: Anisolabididae)" (On-line). Featured Creatures. Accessed January 03, 2021 at https://entnemdept.ufl.edu/creatures/veg/ringlegged_earwig.htm .
Klostermeyer, E. 1942. The Life History and Habits of the Ringlegged Earwig, Euborellia Annulipes (Lucus) (Order Dermaptera). Journal of the Kansas Entomological Society , 15(1): 13-18. Accessed January 03, 2021 at https://www-jstor-org.ezproxy2.library.colostate.edu/stable/25081661?seq=1#metadata_info_tab_contents .