In the bristly earwig Echinosoma horridum, the male’s genitalia are nearly as long as the rest of his body, and the female’s genitalia almost four times as long as the rest of hers.

Earwigs as a whole go back more than 200 million years. Male earwig pinchers (aka cerci) are curved and they use them to seduce females and to fight other males, says Meunier. Female earwigs ...