Why Are There No Insects in the Sea?

The scarcity of insects in marine environments, despite their terrestrial abundance, is a captivating puzzle. Challenges related to respiratory adaptation, ecological roles, and evolutionary ties to plants shed light on this phenomenon. While certain insects overcome respiratory limitations in aquatic habitats, their aerial adaptations limit deep-sea migration, setting them apart from copepods, efficient marine crustaceans. The deep-rooted evolutionary history of copepods, dating back to the Cambrian period, further complicates the potential re-entry of insects into marine ecological niches established by copepods. The unique ecological roles performed by copepods in marine ecosystems, coupled with their ancient origins, provide compelling insights into the contrast between the terrestrial prevalence of insects and their near absence in the sea.