Earwigs, small, elongated insects with distinctive pincers at the rear of their abdomens, have little reason to enter open water. While many earwig species are attracted to damp environments, they typically avoid open water. Yet past studies have found that European earwigs infected with a parasitic roundworm called Mermis nigrescens tend to head toward open water. The molecular and biological reasons for this unusual behavior have not been fully uncovered.