Common Earwig

• Its pincers (cerci), larger and more curved in the male, are used in defence and in contests between males.
• It eats aphids, insect larvae, rotting plant matter and soft fruit.
• It has been widely introduced to North America and Australia.
• It does not crawl into ears. The belief is ancient and sits in its very name in several languages, but it has no basis at all: it is no more likely to enter an ear than any other insect looking for a crevice.
• The pincers on the abdomen are the cerci, and they serve to unfold the wings, for defence and in courtship. The male's are curved and the female's straight, which allows the sexes to be told apart at a glance.
• Its wings are extraordinary: they fold down to a tenth of their surface area, stowed beneath tiny wing cases, with a folding pattern more efficient than any technical origami. Their study has inspired the design of deployable structures in engineering.
• And it almost never flies, despite all that unfolding.
• The female tends her clutch: she spends the winter underground with the eggs, cleans them one by one to keep fungi off, rearranges them and afterwards feeds the young. It is one of the most elaborate examples of maternal care among non-social insects.
• In orchards and gardens it is mostly beneficial: it eats aphids, psyllids and insect eggs, though it also damages soft fruit and flowers.

Skeleton type

Invertebrate - chitin exoskeleton (insect)

Habitat & environment

Gardens, orchards, crevices and damp ground across Europe; widely introduced to North America and Australia

Birth weight

Eggs laid in an underground burrow and actively tended by the mother

Size at birth

A nymph like a miniature adult on hatching, with no developed wings

Sexual maturity

Once the 4 nymphal stages are complete (several months)

Gestation / incubation

20-70 days depending on the time of year (faster in summer, slower in spring)

Litter / clutch size

30 to 55 eggs in the first clutch, with a smaller second one

Sources consulted: University of Florida Entomology (EENY483); PMC (Australian lifecycle study, genome assembly study); OpenLearning.blog; Beetlesbug.com; Penn State Extension