Pygidicranidae Aphychididae

The Earwigs (Dermaptera)

Introduction

Earwigs are a relatively common, if little known insects, typified by Forficula auricularia the common European Earwig. Which can now be found in most temperate and many tropical countries due to its fondness for potted plants as a home. There are around 1 200 species of which the rare, if not extinct Labidura herculeana from St Helena is the largest at around 8 cm long.

The name 'Earwig' is possibly a misinterpretation of 'Earwing' a reference to the small tegmina (hardened forewings). If this is true it may well be partially responsible for the mistaken belief that they will crawl into a sleeping persons ear and then burrow into their brain, thus killing them.

Earwigs are hemimetabolous (i.e. the larval forms look like small adults except for the lack of wings) and have about 4-5 larval instars. They have biting/chewing mouthparts, very reduced forewings (Tegmina) and much folded hindwings which are hidden beneath the reduced forewings or else no wings at all. The antennae are filiform (long and thin) with 10 to 50 segments and the compound eyes are well developed, except in the Arexeniina, while ocelli are absent. They have a generally narrow body with the abdominal cerci enlarged and sclerotized to look like a pair of forceps except in the Arexeniina and Hemimerina, despite belief to the contrary these have no poison glands attached to them.

 

 

Ecology

Earwigs are unusual among insects in that the females of all species studied so far exhibit maternal care, of both the eggs and the early instar nymphs. Adults over winter, at least in temperate climates, in the soil. In Spring the female, sometimes assisted by the male builds a brood chamber or nest underground or within a mound of rotting vegetation, or in some species such as Forficula auricularia often under a rock. After mating the eggs are laid, commonly at night and generally before the eggs hatch the female evicts the male from the nest. The female attends the eggs carefully, turning them regularly and cleaning them until they hatch. After the eggs have hatched the female leaves the nest to forage for food some of which she feeds to the newly hatched nymphs. The nymphs remain in the nest in a huddle while she is away. The length of time that the female continues to brood and protect her young differs between species and it often ends when the nymphs start to forage for themselves, though it may last into the nymphs third instar in Forficula auricularia.

Earwigs are omnivorous, and will feed on dead plant material and dead or slow invertebrates, at least two families are known to be commensal or ectoparasites with mammals, one with about 10 species (Hemimeridae, i.e. Hemimerus talpoides) on different species or subspecies of Rats in South Africa, and one with only two species (Arixeniidae Arixenia esau and Arixenia jacobsoni) on a species of Bat in South East Asia.

Though Earwigs will use their forceps in self defense there is no evidence to support the belief that they use their forceps to hunt other smaller insects.

 

 

Taxonomy

The Cladistic View at the Tree of Life

Order := Demaptera

Suborder := Forficulina
Superfamily := Pigidicranoidea
Superfamily := Labiodea
Superfamily := Forficuloidea
Suborder := Arixeniina

Picture Parade

Labidura riparia 27K jpg

Other Earwig Web Sites


Earwigs of Japan
Earwigs: Another Accidental Invader
Predator Focus: Earwigs
Earwigs and The Ecosystem Tom Ellis Michigan State University Extension
Purdue University: Earwigs In Homes
Earwigs:- Virginia Co-operative Extension
Earwigs:- Oregon State University,
Earwigs:- Ohio
Earwigs:- Michigan State University Extension
Earwigs:- University of Vermont Extension
Earwigs:- Ohio State University Extension Factsheet
Pillbugs, Centipedes, Millipedes And Earwigs
Dermaptera catalogue at University of Michigan Museum of Zoology
Species List University of Michigan Museum of Zoology

Bibliography (Books)


Dermaptera. Eudermaptera I by H. Steinmann
Dermaptera. Eudermaptera II by H. Steinmann
Fauna of India and the Adjacent Countries: Dermaptera Part 1 - Super Family: Pygidicranoidea by G. K. Srivastava
World Catalogue of Dermaptera by H. Steinmann
Dermaptera Species File: A Systematic Catalog (Later 1998)
Zoological Catalogue of Australia, Volume 23: Archaeognatha, Thysanura, Blattodea, Isoptera, Mantodea, Dermaptera, Phasmatodea, Embioptera,


 

Acknowledgements

The images pygidicr.jpg and aphychid.jpg used at the top of this page courtesy of the :-
Department of Entomology of the University of Queensland Australia.

 

 

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This page was designed and written by Mr Gordon Ramel

 

 

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