FAMILIES OF EARWIGS (DERMAPTERA) OF
BRITISH COLUMBIA

by
R. A. Cannings and G. G. E. Scudder 
Copyright © 2005 - All rights reserved

Key to Families of Dermaptera

1. Second tarsal segment distally prolonged under third segment, or with latter arising near dorsal sides of second tarsal segment ..................................Forficulidae

- Second tarsal segment not prolonged under third or distal segment..................... 2

2. Moderate to large wingless insects, at least 15 mm length; males with double penis lobes ..................................................................................... Anisolabididae

• Small, wingless insects, less than 10 mm in length; males with single penis lobe
  ............................................................................................Spongiphoridae

 

Description of Families

Family Anisolabididae (long-horned earwigs)

The Anisolabididae are usually wingless, medium to large sized earwigs with strong, asymmetrically shaped forceps, especially in the male (“Anisolabis” means different forceps: the right forceps, in dorsal view, is more strongly bent inward than the left one). In Canada the family has two genera, each with a single species on both the Atlantic and Pacific coasts. Anisolabis maritima (Bonelli) (Seaside Earwig) is large (15-30 mm long) and dark brown-black with pale yellow legs. It was first recorded in 1926 at Departure Bay, Nanaimo, but is now known from many beaches on the British Columbia coast. Early provincial accounts tied its presence to the Japanese fishing fleet, and locally it has been called the Japanese Earwig, but it is not from Japan. It probably originally came from coastal Africa, but it is now cosmopolitan, especially near seaports. It lives under drift logs, seaweed and other debris near the high water mark where it feeds on small crustaceans and insects. It can capture prey with its forceps and holds the captive while it is devoured. On Vancouver Island the life cycle lasts one or two years. The eggs laid in late spring or summer and the nymphs overwinter; adults appear the next summer or the following spring.

Euborellia annulipes (Lucas) (Ring-legged Earwig) is 9 to 15 mm long, dark brown, and has yellow legs with dark bands. Canadian populations are wingless. Its original range is unknown, but probably came from coastal Africa; it is now cosmopolitan near coastal towns and cities. In Canada, its populations do not seem to flourish long before declining. The Ring-legged Earwig first appeared in the province in 1916, when it was found on a ship in Vancouver harbour. This was the first Canadian record, but apparently, no population became established. In 1927 Euborellia was well established in the Empress Hotel gardens in Victoria and lived there at least three years. Unlike Anisolabis maritima, this species is not restricted to sea beaches, and can live in greenhouses and warehouses as well as gardens. Two generations per year may occur.

Family Forficulidae (common earwigs)

The Forficulidae is the largest family of earwigs, with 250 species worldwide. There are two species known in North America. One, Doru aculeatum (Scudder) is the only native species on the continent, occurring in southern Ontario and the eastern United States; the other is Forficula auricularia Linnaeus (European Earwig), the most successful and familiar earwig immigrant to Canada. Adults are 9 to 15 mm long, red-brown to black, with the antennae, legs and forewings yellowish. They are winged, but seldom fly. The male’s forceps are curved, the female’s are almost straight (“Forficula” means little scissors or forceps). This species originated in western Europe. It was collected in eastern Newfoundland in the 1830s and was established on the northeast and northwest coasts of the United States by the early 1900s. It was recorded in Seattle in 1915 and a year later was common in Vancouver. It is now widespread over much of the province, at least as far north as Prince George in the Interior and Graham Island on the coast.

Family Spongiphoridae (spongiphorid earwigs)

The Spongiphoridae is a widely distributed family with about 240 species, mainly in the tropics. One species, Labia minor (Linnaeus) (Least Earwig), lives in southern British Columbia; it is reported from the Shuswap and Okanagan in the Interior and from the Lower Mainland and Vancouver Island on the coast. It probably originally came from the Mediterranean Basin or Africa, but it probably arrived in eastern North America from Europe in the ships of early colonists. It was first recorded in British Columbia in 1917 at Salmon Arm. The Least Earwig is a tiny species, only 4 to 7 mm long, and the body is thickly clothed with fine yellow hairs. It is strongly winged and flies well, even in the sun, but like other species it is mostly nocturnal. It frequently is attracted to lights at night. Apparently, the forceps are used to expand the wings before flight.