An earwig jar is actually a kind of insect hotel specially designed for earwigs. The pot is a lure for the earwigs and offers them a safe place to nest and hibernate. Earwigs sleep during the day and are prone to dehydration. Therefore, they like to take refuge in dark, sheltered places. The pot also protects them from wind, sun and birds.
Earwigs are very useful insects, as they are natural pest controllers, such as aphids, scale insects and flies. They sleep during the day, but come out at night and eat all those annoying creatures. No wonder people have fruit trees or other earwig-prone plants in their gardens. If you are quick enough, earwigs will surely help to remove any infestation! Earwigs do the same job at night as ladybirds do during the day.
Hang the pot in a sheltered spot amongst flowers, in a tree or place the pot on a fence. It is best to fill the post with wood wool, dried long grass, straw or hay. Keep in mind that earwigs cannot fly. Therefore, place the pot near plants where you do not want aphids.