European earwigs, the only species of earwig found in Wisconsin, are long, thin insects with pincer-like appendages on their abdomen. Red-brown or black in color, they are typically less than an inch in length. They are typically scavengers that feed on dead plant and animal matter. It is not uncommon for them to feed on small garden pests or the root systems of garden plants, though.
European earwigs are most active at night. During the day they will often hide in fruits, flowers or leaves, which is how they usually end up inside homes. They can also be found hiding under boards, stones, or other debris. Their thin bodies allow them to gain access to even the smallest of crevices. Paired with their speed, this can lead to them being a hard insect to get out of your home once inside. However, it is unusual for them to breed once inside your home, and they will eventually die off.
Earwig eggs are laid in small batches or clutches in an underground chamber. These chambers can be as deep as six feet below the surface. The adult earwigs will spend the winter hibernating with the clutch of eggs. Upon the arrival of spring, the female earwig will actually guard the eggs and the newly hatched young, an uncharacteristic behavior for most insects. After the first molt, the young leave the nest and fend for themselves, and the adult female will die. The young typically reach adulthood by the fall, and the cycle repeats.