In freshwater lakes, ponds, and rivers in Europe and Asia, a spider spends virtually its entire life below water, catching prey, mating, laying eggs, resting, and overwintering. Called diving bell spiders or simply water spiders (Argyroneta aquatica), they are the only spiders that breathe air underwater.
Diving bell spiders have a very dense layer of hydrophobic (water-repelling) hairs on their abdomen and legs that they use to hold a bubble of air. They create a “diving bell” by spinning an underwater web to hold the air bubble. The web is made of silk and a specially-designed and unknown protein-based hydrogel. They spin these sheets between submerged water plants and inflate them with the air held by the spider’s hydrophobic hairs. The silk is waterproof but porous enough to allow gas exchange with the surrounding water. There is a net diffusion of oxygen into the bell and a net diffusion of carbon dioxide out.
Nitrogen escapes from the bell as this process continues, so the bubble size decreases, and the spider has to bring new air in periodically to retain the bubble’s size. However, this system is so efficient that they may not have to add air for more than a day. By being underwater their whole life, diving bell spiders have only frogs and fish as their predators. They play an ecological role in the water body by eating aquatic crustaceans and insects such as mosquito larvae.
God has designed many different systems to allow balance in nature. When humans upset the balance, we create problems. The more we study the less visited areas of planet Earth, the more examples we find of unique life forms. We also find ways of copying God’s designs to create new materials and new ways to improve our living conditions.
— John N. Clayton © 2022
References: Science News, July 2, 2011, page 14, and wikipedia.