How can insect breath under water?

There are hundreds of species of insects that live mainly in water where there is more food on the shore. MIT mathematicians discovered how bugs can breathe underwater.

Thanks to a strong, waterproof 'coat', these insects kept a thin layer of air on their bodies when diving. Air bubbles not only serve as a limited source of oxygen, but they also allow insects to absorb oxygen from the surrounding water environment.

John Bush, an associate professor of applied mathematics and co-author of the study, said: 'Some insects have adapted to underwater life by using air bubbles like a leaf. external lungs'.

Thanks to those air bubbles, insects can stay under the water indefinitely and can dive as deep as about 30 meters, according to research by Bush and Morris Flynn, formerly an applied math teacher. Some species, such as Neoplea striola, which are native to New England, even hibernate under water for a long winter.

Notonecta rice beetle hangs upside down under the water surface.Its respiratory bubble surrounds the entire body size.(Photo of John Bush and Morris Flynn)

This phenomenon was first observed many years ago, but MIT researchers are the first to calculate the maximum depth when diving while describing how air bubbles can be maintain when insects dive deeper than water where water pressure can break them.

The new study will be published in the August 10 issue of the Journal of Fluid Mechanics. The study showed a delicate equilibrium between air bubble stability as well as insect's respiratory needs.

The stability of air bubbles is maintained by the hair on the insect's abdomen , which helps to prevent water on the surface. The hair along with the wax on the surface prevents water from flooding the breathing hole - tiny holes in the belly of the insect.

The distance between the hairs is also particularly important. The closer the hairs are to each other, the greater the mechanical stability as well as the ability to withstand the pressure of air bubbles before being broken.

However, this stability is also included. If the hairs are too close together, there is not enough surface area to breathe.

The Dolomedes triton spider uses an air layer of about 0.2mm thick as an oxygen source.(Photo: John Bush and Morris Flynn / ScienceDaily)

Flynn, who is currently an assistant professor of mechanical engineering at the University of Alberta, said: 'Since air bubbles play a role as an external lung, its surface area must be large enough to facilitate communication. Easy gas'.

Researchers have created a mathematical model to calculate the above factors and allow them to predict the depth to which the insects can dive. They found that there is a maximum depth of air bubbles that can withstand, and also a minimum depth that air bubbles cannot meet the respiratory needs of insects.

Although researchers found that insects could dive as deep as 30 meters below the surface , they rarely risk diving deeper than a few meters because there are other environmental factors such as their light, availability and availability. bait or presence of predators.

The first researchers were very interested in the insect's outer lungs when they accidentally caught an underwater breathing species while searching for water spiders. A few years ago, Bush and his colleagues figured out how water spiders use surface tension to slip on water surfaces.

Other researchers have discovered systems that can regenerate the outside lung at a greater rate to be able to use it with humans. A research team from Nottingham Trent University showed that the porous cavity surrounding impermeable materials is supplied with oxygen thanks to the thin layer of air on the surface. The surface area needed to support very large human breathing activity exceeds 100 m2. However, there are other methods to apply this technique. For example, the oxygen supply device is needed by fuel cells to charge energy for automated underwater vehicles, for example.