You’ll find earwigs in lettuce but never in an ear

EARWIGS are not popular insects.

They have nasty-looking pincers on their rear ends and long antennae at the other end; they move in a rapid, snake-like way; and they have a habit of turning up in the wrong place – the wrong place being a lettuce brought in from the garden, or lurking in the folds of a clean towel.

Earwigs are relatively harmless and interesting. The first prejudice that has to be dispelled is that they creep into people’s ears and bore into their brains to lay their eggs. This is an ancient myth. The name ‘earwig’ comes from Old English and means ‘ear insect’. There are similar names in most European languages.

Earwigs are nocturnal and like to wriggle into very tight places to sleep during the day, and they prefer these places to be slightly damp. That’s why you find them in lettuces, or dahlias, or globe artichokes – but never in ears. Let’s examine those fearsome pincers: the proper scientific name for them is ‘cerci’. Very young earwigs don’t have any, and in the common European earwig males have curved pincers and females have straight ones.

There’s some argument among the experts about the function of the pincers. Earwigs have been observed using them to hold prey, and to hold each other when they’re mating. One theory suggests they use them to fold their very large, fine wings back into the wing cases on their backs, but there doesn’t seem to be much evidence to back this up. The one thing they certainly never use them for is pinching people.

Yes, most species of earwig, including the common European one, which is the main one found in Ireland, do have wings and most of them can fly. There is another mystery surrounding this, because, although they can fly, they almost never do. Most earwigs carry these large wings around with them all their lives, without ever using them. They’re omnivorous. Most species are largely vegetarian, but occasionally catch and eat small live prey, such as mites and tiny insects. They will eat crops like lettuce and cauliflower, and bore their way into windfall fruit. But, although they have been known to damage sweet-corn by eating the silks required for pollination, they are seldom a serious garden or farm pest. They have caused problems by crawling into computer keyboards for a nap.

And they do make very good mothers. Females lay eggs in batches of 20 to 100 each, depending on the species, usually in spring or autumn. They then guard them from predators, while they develop, and continually clean them – this is necessary because of a fungus that grows on the eggs and must be licked off. After about 10 days, the eggs hatch – it can take longer for eggs laid in the autumn. Then, the mother looks after the hatchlings for about another 10 days, until they are big enough to care for themselves. This is an unusual level of care in the insect world.

The baby earwigs are called nymphs and go through five or six ‘instars’ before they become adults. This means they shed their hard outer shell and grow a new and larger one.

The Common European earwig, Forficula auricularia, which is the one you’re most likely to encounter in this country, is about 12mm long when fully grown. But if you dislike earwigs, I would recommend you to avoid the remote Atlantic island of Saint Helena, because they have a species that reaches 80mm in length.

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