Meet the “Scuba Spider” – the only spider that lives exclusively underwater. Generally known as the diving bell spider or the water spider, this fascinating underwater creepy-crawly survives submerged in a rather incredible way: In the absence of gills, it makes do with its own “scuba tank” – an air bubble.
Evolution has granted this little arachnoid some nice perks to enable its underwater life. Both its abdomen and legs are densely clothed in short hairs that trap air and form bubbles when it is submerged in water. This is its “scuba tank”, allowing it to breath and to go about its business beneath the fresh ponds and lakes of northern Europe and Asia. When it runs low on oxygen, the spider simply returns to the surface to replenish its supply. Notably, the air bubble actually changes the colour of its body, giving it a silvery appearance compared to a velvet-grey one when outside the water.
In accordance with a preference for an aquatic existence, and rather interestingly, this spiders creates an underwater home, or retreat. This is a large air bubble like an open diving bell. It is formed among underwater plants and weeds and it can be stocked up with oxygen as the spider travels back and forth from the surface with the air bubbles around its body. As the home fills with air, it becomes bell-shaped and takes on a silvery appearance. In fact, Argyoneta, the scientific name for the spider, comes from the Latin for silvery net, and was given in reference to this aquatic home.