How Do Spiders Need Oxygen to Live?
WouterSpiders breathe through a number of different mechanisms. Some spiders have an aquatic lung, which allows them to stay submerged for long periods of time. Others have gills, which extract oxygen from water. They can also breathe through passive diffusion, which occurs when the tracheae (shallow openings in the body) spread the oxygen and carbon dioxide around the spider.
In the past, scientists did not know how diving bell spiders could survive under water. They thought that the amount of oxygen taken up by the spider was not sufficient for its metabolic needs. But, after studying several sea spiders, Dr Woods discovered that the spiders carried the oxygen in their guts.
A pair of scientists spent a summer collecting spiders. They watched the spiders spin silvery nets and fill air bubbles. They then measured the oxygen levels in the air bubbles.
They found that the bubbles contained more nitrogen than oxygen. As the oxygen concentration decreased, the nitrogen concentration in the bubble increased. That’s because the oxygen diffuses more easily in water than nitrogen. That’s why some spiders die within 35 minutes of exposure to a 4% oxygen atmosphere.
When they studied the behavior of the spider, they noticed that the spider enlarged the bubble when it was laying eggs or catching prey. But it had to refill the bubbles periodically. When the air in the bubbles became too low, the bubble collapsed.
The bubble eventually collapsed because the nitrogen in the air bubble began to diffuse out of the bubble. This resulted in an increase in the oxygen concentration in the water outside the bubble.
