The diving bell and the water spider: How spiders breathe under water
Gazing into the depths of a pond, it's hard to miss the insects that whirl and zip beneath the surface. However, only one species of spider has joined them: the diving bell spider, Argyroneta aquatica. 'It is an iconic animal; I had read about the spider as a small boy in popular literature about ponds,' says Roger Seymour from the University of Adelaide. According to Seymour, each spider constructs a net of silk in vegetation beneath the surface and fills it with air carried down on its abdomen. The spiders spend their entire lives submerged and even lay their eggs in their diving bells. Having already used an oxygen-measuring device called an optode to discover how aquatic insects extract oxygen from water through thin bubbles of air stretched across their abdomens, Seymour was looking for other small bubbles to test his optode. 'The famous water spider came to mind,' remembers...