Why Insects Are Rarely Found In The Ocean

Similar to outer space, the ocean remains a vast mystery, and scientists are continuously delving into its depths to unravel its secrets. Teeming with diverse aquatic life that never fails to astonish explorers, the ocean poses an intriguing question: why are there so few insects within its realms?

Insects, widely regarded as the most successful organisms on Earth, constitute a significant portion of the biomass of all land animals. Numerous species thrive on land, playing vital roles in terrestrial ecosystems. Despite their abundance on land, insects are conspicuously scarce in marine environments, prompting scientists to seek answers. A query on the Quora social media platform pondered, “Why are there no insects in the oceans?”

A Zoology book author responding on Quora explained that scientists have yet to discover approximately one million insect species, estimating that at least 10 million insect species exist. Insects, constituting 90% of animal life on the planet, exhibit remarkable adaptability, surviving in extreme environments such as the scorching heat of the Sahara desert and the notorious Dry Valleys of Antarctica. Notably, sea skaters represent the sole insect type capable of inhabiting the open ocean, with five species capable of walking on the water’s surface.

Another user suggested that insects are well-adapted to land, and differences in oxygen transfer between freshwater and ocean environments may act as a barrier to their marine colonisation.

Scientific research from Tokyo Metropolitan University, led by Tsunaki Asano, sheds light on this enigma. The study reveals that insects, through evolution, developed a unique chemical mechanism to harden their shells using oxygen. This adaptation provides them with an advantage on land but proves disadvantageous in open waters.

Researchers identified an enzyme, Multicopper Oxidase 2, responsible for shell hardening in insects, aiding their land adaptation. The study posits that the ocean’s less hospitable environment, with lower oxygen levels, hinders the survival of insects, emphasizing the importance of abundant oxygen in facilitating their adaptation to land.