Like a diver whose tanks are running low, underwater spiders know when it’s time to surface for a refill. The water spider weaves an underwater air chamber for feeding and breeding, and a study in the October issue of the Journal of Experimental Zoology Part A: Ecological Genetics and Physiology shows that the chamber also plays a role in respiration. When researchers lowered the level of oxygen in the chamber, the spiders brought air bubbles from the surface to replenish the gas. Thus the spiders are actively managing the chambers as external respiratory devices, an adaptation unseen in any other animal. (Photo: Niels Sloth/Biopix.dk)
