Many insects can survive for long periods of time under water, but the brightly-colored Hawaiian Hyposmocoma moth has a unique evolutionary trait: It can live half its life underwater. Scientists call it the only known "perfectly amphibious" creature.
A study by environmental scientists published today in PNAS explores the life of this astonishing moth, whose larvae can live weeks underwater - or on dry land. Natives of Hawaiian mountains, Hyposmocoma spend the first weeks of their lives as larvae before they weave themselves into cocoons and emerge as flying moths. During this larva stage, they can choose to live in rushing streams, attaching themselves to rocks with silk drag lines, or they can nestle in nearby volcanic rocks. They remain protected in part by "casings," shell-like coverings for their bodies that come in a variety of sizes and colors.
According to a release about the study:
Daniel Rubinoff and Patrick Schmitz observed larvae of the moth genus Hyposmocoma feeding and breathing both underwater and away from streams on dry rocks and sequenced the caterpillars' genes to reconstruct their evolutionary history. Although many insects are able to withstand extreme conditions in a dormant state, no previously known insect can survive an entire life cycle above and below the water's surface.
How do they survive underwater? Rubinoff and Schmitz aren't entirely sure, but they speculate in their paper that "they likely rely on direct diffusion of oxygen through the hydrophilic skin along their abdomens." Because they're essentially sucking oxygen out of the water using their bellies, these larvae can only survive in fast-flowing streams full of water bubbles. They die in stagnant water.
Though Hyposmocoma are a land-dwelling creature, the scientists have discovered that they've evolved this aquatic ability no less than three times during their long evolution on the Hawaiian Islands - likely because they exist in a habitat where food is as likely to come from the water as it is from dry land. They call these insects "unique" and "remarkable" because no other creature has yet evolved the ability to live entirely submerged or entirely on land.
Isn't it time we sequence the genomes on these little guys so we can do a little genetic engineering on humans to create superhuman mutants with Aquaman abilities?