The female digs a chamber in soil or under a stone in late autumn and lays a clutch of several dozen eggs. She then stays with them through the winter. Rather than sitting passively, she repeatedly picks up individual eggs, moves them, and cleans their surface with her mouthparts.
The cleaning has a measurable function. Eggs left unattended in damp soil are rapidly overgrown by fungi, and experiments removing the mother show far higher mortality from fungal infection than in guarded clutches. She also repositions the clutch in response to moisture and disturbance, and defends it against small predators.
Care continues after hatching. The mother remains with the first-instar nymphs, and food is transferred, including by regurgitation, until the young disperse. The pincers themselves, which give the insect its reputation, are used in defence and in male contests and can be spread in a threat posture, but they are harmless to people. The old belief that earwigs enter human ears to burrow into the brain has no basis; the name is much older than any evidence for the behaviour.