Earwig

Earwig
Fossil range: Jurassic to Recent
Common earwig, Forficula auricularia
Common earwig, Forficula auricularia
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Hexapoda
Class: Insecta
Order: Dermaptera
De Geer, 1773
Families

Suborder Archidermaptera †
Suborder Forficulina

Pygidicranidae
Diplatyidae
Anisolabididae
Labiduridae
Apachyidae
Labiidae
Chelisochidae
Forficulidae

Suborder Hemimerina

Hemimeridae

Suborder Arixenina

Arixeniidae

Earwigs is the common name given to the insect order Dermaptera characterized by membranous wings folded underneath short leathery forewings (hence the literal name of the order—"skin wings"). The abdomen extends well beyond the wings, and frequently, though not always, ends in a pair of forceps-like structures termed cerci. The order is relatively small among Insecta, with about 1,800 recorded species in 10 families. Earwigs are, however, quite common globally. There is no evidence that they transmit disease or otherwise harm humans or other animals, despite their nickname pincher bug.

Contents

Etymology

Earwig is derived from Old English ēare "ear" and wicga, "insect". (Wicga is in turn related to wiggle, and ultimately to other words implying movement, including way and vehicle, all from PIE *wegh-.) The name comes from the old wives' tale that earwigs burrow into the brains of humans through the ear and therein lay their eggs.[1] Earwigs are omnivores that are predisposed to hiding in warm humid crevices and as such one may crawl into a human ear canal. This is not, however, a location where they are frequently found.[2]

Other languages have words based on the same premise: German Ohrwurm (also: Ohrkneifer, "ear pincher"), French perce-oreille, Danish ørentviste, Slovak ucholak (ucho = ear, lak = scare), and Hungarian fülbemászó ("crawler-into-the-ear"). English has derived a verb from this, to earwig, meaning "to fill someone's mind with prejudice by insinuations" or "to attempt to influence by persistent confidential argument or talk".[3] The German word Ohrwurm has the derived meaning "an annoying tune which I can't get out of my head" (see earworm). Hungarian also uses the phrase fülbemászó dallam with similar meaning as the German above, although without the negative overtones.

Classification

Four suborders within the Dermaptera have been established: [4]

Appearance and behaviour

Two earwigs from Australia compared to a CF card—63 mm.

Most earwigs are elongated, flattened, and are dark brown. Lengths are mostly in the quarter- to half-inch range (10–14 mm), with the St. Helena earwig reaching three inches (80 mm). Cerci range from nonexistent to long arcs up to one-third as long as the rest of the body. Mouthparts are designed for chewing, as in other orthopteroid insects. Flight capability in Dermaptera is varied, as there are species with and without wings. In those earwigs that have wings (are not apterous), the hindwings are folded in a complex fashion, so that they fit under the forewings. Most species of winged earwigs are capable of flight, yet earwigs rarely fly around.

Female (cerci not hooked).
An earwig from the Western Ghats
Common Earwig

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 also been observed in use for holding prey, and in copulation. The forceps tend to be more curved in males than in females.

Most earwigs found in Europe and North America are of the species Forficula auricularia, the European or common earwig, which is distributed throughout the cooler parts of the northern hemisphere. This species feeds on other insects, plants, ripe fruit, and garbage. Plants that they feed on typically include clover, dahlias, zinnias, butterfly bush, hollyhock, lettuce, cauliflower, strawberry, sunflowers, celery, peaches, plums, grapes, potatoes, roses, seedling beans and beets, and tender grass shoots and roots; they have also been known to eat corn silk, damaging the corn. Typically they are a nuisance because of their diet, but normally do not present serious hazards to crops. Some tropical species are brightly colored. Occasionally earwigs are confused with cockroaches because of their cerci and their long antennae.

Earwigs are generally nocturnal and can be seen patrolling household walls and ceilings. Interaction with earwigs at this time results in a defensive free fall to the ground below, and the subsequent scramble to a nearby cleft or crevice.

Earwigs are also drawn to damp conditions. During the summer, they can be found around sinks and in bathrooms. Earwigs tend to gather in shady cracks or openings or anywhere that they can remain concealed in daylight hours. Picnic tables, compost and waste bins, patios, lawn furniture, window frames, or anything with minute spaces (even artichoke blossoms) can potentially harbor these unwanted residents. Upon gaining entry to the basement and living areas of the home, earwigs can easily find cover in undisturbed magazine and newspaper piles, furniture/wickerwork, base boards, carpeted stairways, pet food dishes, and even inside DVD cases and keyboards. Earwigs are exploratory creatures and are often found trapped in poison baited cups or buckets of soapy water.

Pest control

Earwigs can be considered in some ways a beneficial part of the garden, especially when they prey on other insects, but they can become a nuisance because of their habit of positioning themselves within leaves and feeding on soft plant tissues. They prefer cool, moist places, and a rolled up damp newspaper placed where earwig activity is suspected can be effective in collecting them. The newspaper can then either be discarded or shaken out. Placing diatomaceous earth in key spots around the home (bathroom, baseboards, window frames) can be a long-term repellent.

Notes

  1. ↑ Oxford English Dictionary on "Earwig".
  2. ↑ Fabian Haas, Dermaptera — Earwigs, Tree of Life web project, http://www.tolweb.org/Dermaptera 
  3. ↑ dictionary.com: earwig
  4. ↑ Susan M. Rankin and James O. Palmer (pp. 297-299) in Resh, V. H. & R. T. Cardé (Editors) 2003. Encyclopedia of Insects. Academic Press.

References

External links