Dermaptera is the insect order that contains all earwigs, a group of roughly 2,000 described species found on every continent except Antarctica. Despite their modest size and nocturnal habits, earwigs are genuinely remarkable insects: they carry forceps-like pincers on their rear end, fold their hindwings into the most compact wing packages of any insect, and display a level of maternal care that is unusual among non-social insects. The order’s name comes from the Greek words for “skin” and “wing,” referring to the tough, leathery forewings that cover the delicately folded hindwings beneath. Their common name, meanwhile, traces back to an ancient and spectacularly wrong superstition about ears and brains.
The Forceps That Define the Order
If you pick up an earwig, the feature you notice first is the pair of curved, pincer-like structures at the tip of the abdomen. These are modified cerci, appendages that in most other insects are small, soft, and unremarkable. In earwigs they have been hardened and reshaped into tools that function as weapons, courtship aids, and general-purpose manipulators. Males in many species have longer, more curved forceps than females, and in some species males come in two distinct forms: one with large, exaggerated forceps and another with shorter ones.
Research on the toothed earwig, Vostox apicedentatus, showed that forceps serve as both weapons and display structures. In laboratory trials, dominant males used their forceps more frequently during contests with rival males, and the winner of those contests gained exclusive access to nearby females. Males also deployed their forceps during courtship, while females rarely used them in male-female encounters. The behavioral repertoire involving forceps was broader in males than females, which points toward sexual selection as a driving force behind the elaboration of these structures.1Behavioral Ecology. The evolution of sexually dimorphic earwig forceps: social interactions among adults of the toothed earwig, Vostox apicedentatus
You might expect the two male forms to show wildly different scaling relationships between body size and forceps size, but a study of the European earwig found that forceps allometry was broadly similar across male morphs and even across different rearing environments, with only limited divergence associated with the exaggerated form.2PubMed. Sexual dimorphism of weapon allometry in the European earwig In other words, forceps size tracks body size in a fairly predictable way regardless of whether a male ends up with the large or small morph. The mechanisms that trigger one developmental path over the other remain an active area of research.
Wings That Fold Like Origami
Beneath the short, hardened forewings lies one of the more extraordinary engineering feats in the insect world. Earwig hindwings fan out to roughly ten times the area of the folded package, making earwig wing storage the most compact of any insect.3PubMed Central. Earwig fan designing: Biomimetic and evolutionary biology applications The folding pattern combines radial creases (like a hand fan) with transverse folds, allowing the wing to collapse into a tiny rectangle tucked under the forewings.
What makes this system especially interesting is that the folding is largely passive. Detached wings from preserved specimens still fold correctly, which tells researchers that the mechanism is built into the wing structure itself rather than requiring active muscular effort. The key material is resilin, a rubber-like protein distributed along the fold lines that stores and releases elastic energy. Because the wing is in a lower-energy state when folded, it naturally snaps shut once the flight muscles stop holding it open. Resilin placement also prevents the wing from folding the wrong way, acting as a built-in error-correction system.4Journal of Experimental Biology. Foldable insect wings: from folding and unfolding mechanisms to inspired applications – Section: Dermaptera
Earwigs are not strong fliers. Flight-speed measurements of the lesser earwig, Labia minor, recorded speeds of only about 0.2 to 0.5 meters per second during flapping flight, placing them squarely among slow-flying insects. During flight, only a small basal region of the wing is actively driven by muscles; the rest of the wing responds passively to the movement and surrounding airflow. The leading edge is kept relatively rigid while an elastic joint allows the outer portion to flex independently.5Biology Open. Simultaneous optimisation of earwig hindwings for flight and folding – Section: Free flight analysis Many species rarely fly at all, but some are attracted to lights at night, which is how they sometimes turn up in unexpected places like upper-story apartments.
Earwig Mothers and the Evolution of Family Life
Most insects lay eggs and leave. Earwigs are different. Females of many species guard their egg clutches for weeks or months, grooming the eggs, repositioning them, and defending them against intruders. This behavior, called subsocial care, is one of the traits that makes Dermaptera a frequent subject in evolutionary biology research. Scientists studying the origins of social behavior in insects use earwigs as a model because their level of care sits between solitary species and the fully social colonies of ants and bees.
The grooming is not just tidying up. When European earwig mothers attend their eggs, they mechanically remove fungal spores and continuously apply chemical substances, identified as hydrocarbons, to the egg surfaces. In experiments where eggs were deliberately exposed to mold, mothers significantly increased their grooming effort, and attended eggs maintained their surface chemical coating while unattended eggs lost theirs substantially.6Behavioral Ecology. Maternal care provides antifungal protection to eggs in the European earwig Studies of adult female earwigs found that their body surfaces harbor bacteria with potential antifungal properties, and eggs tended by mothers carried higher abundances of these beneficial microbes.7PubMed. Parental Care Alters the Egg Microbiome of Maritime Earwigs
The protective effect can be dramatic. In the earwig Doru luteipes, a species found in South America, removing the mother led to egg infection rates of roughly 48% to 55% when exposed to common insect-killing fungi. Nymph infection was even more striking: maternal care reduced the percentage of infected nymphs from about 78% to just 12% when eggs were exposed to one pathogenic fungus.8Journal of Insect Behavior. Doru luteipes: Susceptibility to Entomopathogenic Fungi and the Role of Maternal Care in the Protection of Offspring Against Infection
Maternal care does come with trade-offs, though. Under food-restricted conditions, having a mother present actually decreased offspring survival to adulthood by 43% in one experiment, likely because mothers and offspring competed for the same limited food. The negative effect persisted even after the young were separated from the mother, suggesting lasting consequences rather than a temporary squeeze.9PubMed Central. When it is costly to have a caring mother: food limitation erases the benefits of parental care in earwigs This finding matters for understanding why maternal care evolved in the first place: the behavior is only favored when environmental conditions, particularly food availability, make the benefits outweigh the costs. In lean times, a mother earwig is essentially another mouth competing with her own offspring.
European earwig mothers also relocate their eggs during winter in response to temperature changes, moving clutches to buffer them against extreme cold. This post-oviposition repositioning strategy adds another dimension to earwig parental investment beyond the grooming and guarding behaviors.10Peer Community Journal. Pre- and post-oviposition behavioural strategies to protect eggs against extreme winter cold in an insect with maternal care
Chemical Weapons and Aggregation Signals
The forceps are not an earwig’s only defense. Many species have abdominal glands that produce foul-smelling secretions, typically containing quinone compounds. These chemicals serve double duty: they deter predators and appear to have antimicrobial properties that help sanitize the earwig’s immediate environment.11PubMed. Multifunctional weaponry: the chemical defenses of earwigs Even larvae produce defensive secretions, though they use different glands than adults do. In experiments with European earwig larvae, the secretion discouraged ant attacks but did not faze spiders, suggesting the chemical defense is tuned to specific predator types rather than being a universal repellent.12PubMed. The chemical defense in larvae of the earwig Forficula auricularia
Earwigs are strongly thigmotactic, meaning they prefer to be in contact with surfaces on all sides, which explains their habit of wedging into crevices, under bark, and beneath flowerpots. This tendency, combined with aggregation pheromones, can lead to large gatherings in sheltered spots.13Encyclopedia of Insects. Dermaptera: Earwigs Research on the European earwig identified the aggregation signal as likely a minor component of male cuticular lipids, with frass extracts and cuticular washings both triggering aggregation behavior in bioassays.14PubMed. Pheromonal basis of aggregation in European earwig, Forficula auricularia L. (Dermaptera: Forficulidae) This is why you often find earwigs in groups rather than singly: they are actively seeking each other out.
Where Earwigs Sit on the Insect Family Tree
Earwigs belong to a larger group of insects called Polyneoptera, which also includes grasshoppers, cockroaches, stick insects, stoneflies, and several other orders. Pinning down exactly where Dermaptera fits within this group has been contentious. Mitochondrial genome analyses have placed earwigs as the sister group to Plecoptera (stoneflies), a result supported with strong statistical confidence across different analytical methods.15PLoS ONE. Complete Mitochondrial Genome of the Free-Living Earwig, Challia fletcheri (Dermaptera: Pygidicranidae) and Phylogeny of Polyneoptera
A 2025 phylogenomic study complicated things further. The previously favored hypothesis that earwigs and the tiny order Zoraptera together formed the earliest branch of Polyneoptera collapsed when researchers used models that accounted for compositional variation across different gene sites. Under the better-fitting model, Zoraptera alone emerged as the earliest-diverging lineage, while earwigs and stoneflies together formed a clade called Dermoplectopterida that branched off next.16PubMed. Phylogenomics resolves the century-old ‘Zoraptera problem’: Zoraptera as the earliest diverging lineage of Polyneoptera So the earwig-stonefly relationship holds up, but the broader arrangement of early polyneopteran branches keeps shifting as analytical methods improve.
Within Dermaptera, the fossil record reaches back to the Jurassic. Transitional fossils from Middle Jurassic deposits in Inner Mongolia, placed in a new family called Bellodermatidae, show an unexpected combination of primitive and derived features that bridges two ancient suborders. These fossils fill a gap in the earwig evolutionary sequence, sitting at the base of the lineage that eventually gave rise to all modern earwigs.17PubMed Central. Transitional fossil earwigs–a missing link in Dermaptera evolution
Pest, Predator, or Both
The European earwig occupies an unusual position in agriculture: it is simultaneously a minor pest and a valued natural enemy of other pests, depending on the crop. In pome fruit orchards (apples and pears), earwigs are effective predators of aphids and psyllids. In one classic experiment, apple trees stocked with five to six earwigs each saw aphid numbers drop from around 500 per tree to fewer than 50 within three weeks, while trees kept free of earwigs had populations climb above 3,000.18Journal of Economic Entomology. Augmentation of European Earwigs (Dermaptera: Forficulidae) for Biological Control of Apple Aphid (Homoptera: Aphididae) in an Apple Orchard Field studies also showed that where earwigs were abundant, fewer than 10% of new growth shoots were infested with woolly apple aphid, compared with 30–35% on trees where earwigs were excluded.19Entomologia Experimentalis et Applicata. Earwig (Forficula auricularia) predation on the woolly apple aphid, Eriosoma lanigerum
Researchers have even explored harvesting earwigs from stone fruit orchards, where they are unwanted, and mass-releasing them in pome fruit orchards to control woolly apple aphid and pear psylla. Multiple orchards receiving mass releases showed reductions in these key pests.20PubMed Central. Turning a Pest into a Natural Enemy: Removing Earwigs from Stone Fruit and Releasing Them in Pome Fruit Enhances Pest Control
On stone fruits and citrus, the picture flips. Earwigs chew shallow holes and tunnels in cherries, with exclusion experiments showing that keeping earwigs off trees reduced fruit damage by 21% to 34% depending on the cherry variety.21PubMed. Cherry damage and the spatial distribution of European earwigs, (Forficula auricularia L.) in sweet cherry trees Young citrus fruit are vulnerable too: earwig nymphs chew deep holes in oranges shortly after petal fall, generating scars that persist to harvest and contribute to fruit quality downgrades.22Journal of Economic Entomology. Characterizing Herbivory by European Earwigs (Dermaptera: Forficulidae) on Navel Orange Fruit with Comparison to Forktailed Bush Katydid (Orthoptera: Tettigoniidae) Herbivory They can also damage foliage and stems of young trees and feed on vegetables, grains, and flowers.23Journal of Integrated Pest Management. Biology and Management of European Earwig in Orchards and Vineyards – Section: Feeding Behavior and Roles in Different Fruit Crops Managing earwigs in agriculture means deciding crop by crop whether the aphid control they provide outweighs the fruit damage they inflict.
The Ear Myth and Where It Came From
The name “earwig” traces back at least to the beginning of the first millennium in old Germanic languages, and nearly every European language has a common name for these insects that references the human ear. The myth that earwigs burrow into sleeping people’s ears and bore into the brain probably originates in the writings of Pliny the Elder in the first century CE.24Acta Musei Silesiae, Scientiae Naturales. Superstitious beliefs about earwigs (Dermaptera) There is zero evidence that earwigs have any special affinity for human ear canals or any capacity to damage the brain. That said, earwigs do occasionally wander into ears, just as various other small insects do, as documented in clinical case reports.25PubMed Central. Earwig Crawling in the Ear: Myth or Truth Their thigmotactic nature means they seek out tight, dark crevices, and an ear canal technically qualifies. But there is nothing intentional or targeted about it, and it happens no more frequently with earwigs than with other similarly sized insects that share human living spaces.
Earwigs That Live on Mammals
Most earwigs are free-living decomposers and omnivores, feeding on decaying plant matter, small invertebrates, and whatever else they encounter on the ground. But two small families have taken a radically different path. Arixeniidae species live on hairless bulldog bats of the genus Cheiromeles in Southeast Asia, while Hemimeridae species live on giant pouched rats in sub-Saharan Africa. Both lineages are epizoic, meaning they live on the surface of their host mammals rather than inside them. Both families are also viviparous, giving birth to live young rather than laying eggs, a trait that is otherwise extremely rare in Dermaptera.26PubMed. Reassessing the phylogenetic position of the epizoic earwigs (Insecta: Dermaptera) These species have lost their wings and have reduced or absent forceps, and they likely feed on skin secretions, fungi, and debris found on their hosts. They are among the strangest members of the order and a vivid example of how specialized an earwig body plan can become under the right ecological pressures.
Earwig-Inspired Engineering
The compact folding of earwig wings has attracted serious attention from materials scientists and engineers. The crease patterns that allow a wing to expand to ten times its stored area and then snap shut automatically are essentially solved problems in deployable structures, the kind of challenge that human engineers face when designing satellite solar panels, pop-up shelters, and foldable electronics. Researchers used X-ray microcomputed tomography to map the precise geometry of earwig wing folds and derived the geometric rules needed to reproduce them artificially.3PubMed Central. Earwig fan designing: Biomimetic and evolutionary biology applications Building on these principles, a team developed a spring origami model inspired by earwig wings that uses the bistable snap-through property to create four-dimensional-printed objects with programmable shape-changing behavior.27PubMed. Bioinspired spring origami The wing’s combination of self-folding, fatigue resistance (thanks to resilin), and extreme compactness represents a design space that origami engineers had not explored before earwig biology pointed them toward it.
Microbiomes and Environmental Monitoring
Earwig family groups shape the microbial communities of their members. Juveniles reared with family members harbored higher abundances of certain bacteria, including both potentially mutualistic strains like Lactobacillus and potentially pathogenic ones like Serratia, compared with juveniles raised in isolation. The pattern mirrors what researchers see in more thoroughly studied social species, suggesting that even the relatively simple family life of earwigs is enough to structure the gut and body-surface microbiome.28Peer Community Journal. Family life and cadmium ingestion independently shape offspring microbiomes in a subsocial insect
Earwigs also show up in environmental monitoring work. Because they are ground-dwelling omnivores that accumulate metals from soil and leaf litter, species like the maritime earwig Anisolabis maritima have been included in bioaccumulation studies assessing heavy-metal contamination. The bioaccumulation factor varied among species and seasons, with some invertebrates classified as concentrators of certain metals, giving researchers a biological snapshot of local contamination that chemical soil testing alone might miss.29PubMed. Assessment of heavy metals in soil, leaf litter, and their bioaccumulation in terrestrial macroinvertebrates in Sohag Governorate, Egypt Winter mortality in European earwig populations is also heavily influenced by environmental conditions: between 60% and 90% of females do not survive winter, with a strong negative relationship between cumulative cold exposure and survival.30Journal of Applied Entomology. Natural and human causes of earwig mortality during winter: temperature, parasitoids and soil tillage Soil tillage practices add another layer of human-caused mortality, which matters for orchardists who rely on earwig populations for natural pest control in spring and summer.