It was more than 70 years ago when people crossed the line between water and land using an aqua-lung.
However, it’s not only human beings who are capable of breathing underwater. In fact, many aquatic insects have been doing it for millions of years. One of nature’s most popular scuba divers is a beetle.
“Water beetles have been breathing underwater since before the dinosaurs existed,” Crystal Maier, an entomologist at The Field Museum in Chicago explained. “It has evolved at least 10 times across the insect tree of life.”
So exactly how do they do it? It’s a little thing called surface tension. It’s the cohesive force between liquid molecules. This attracts them to each other over molecules that they don’t share as many properties with. These liquid molecules then create a film, seemingly an air pocket. For larger species like humans, this film is far from noticeable.
“If you’re a bug the size of a paperclip, in other words, surface tension makes a difference. Harnessing it, some aquatic beetles carry the oxygen they need underwater in the form of a temporary bubble, sort of like a natural scuba tank. Others encase themselves in a layer of air and draw oxygen from it their whole lives,” explains Cheryl Barr, collection manger emeritus at the Essig Museum of Entomology at UC Berkeley.
When that tiny air pocket runs out of oxygen, these beetles simply go back up to the surface and generate another one. Other species known to pull this trick off are diving bell spiders and water scorpions.
When it comes to adaptation, these water beetles are so far ahead of us that it’s pretty scary!