Don Roach, age 10, of San Diego, California, for his question:
How can a spider breathe under water?
Actually she can't. But the spider is a very clever little creature and if there is a way to do the impossible, sooner or later she finds it. As we know, a remarkable spider named Arabella was taken on a space trip to Skylab. Nobody really thought that she could spin her silken web up there where there was no gravity to guide her. But she did. After a few dizzy tries, Arabella spun a perfect web.
Actually a dainty spider web is a small miracle and the talented little spider builds it in less than an hour. We should not be surprised to learn that such a clever creature can do other remarkable things. For example, at least one type of spider can build a sort of aqualung. She likes to live under water but unlike a fish, she cannot absorb her oxygen from the water. So she solves the problem by taking an air supply below.
Spiders, as we know, feed on insects and invent all sorts of clever ways to trap them. Many insects like to live near the water and some of them stride and dance on the surface. And where insects are likely to gather, usually there are spiders around to catch them. In North America we have several large long legged spiders who walk on the water chasing insects that also walk on the water.
But the real water spider lives in Europe and parts of Asia. Though she must have air to stay alive, this remarkable little creature can stay under water for a month or more. No, she does not hold her breath all this time. She brings down air from above and stores it in a small room.
She spins a silken bell under the water. It is large enough for herself and her family of small spiderlings and usually it hangs upside down, dangling from a water weed. It is a waterproof mini¬aqualung.
The air to fill it must come from above the water, so from time to time the spider must go up to the surface. There she forms a sort of basket with her spidery legs and twists and turns to fill the basket with a bubble of air. Then down she comes, grasping her bubble. She hangs upside down under the bell shaped aqualung and as the air is pushed into the bell, it forces out the water.
The air cannot escape because the bell is waterproof and the opening is at the bottom. When the air gets stale, she weaves a new bell and fills it with more bubbles of fresh air from above.
The water spider finds plenty of bugs and beetles below the surface, also the eggs and larvae of other insects. The only reason she needs to come to the surface is to gather fresh air bubbles. She weaves a bell shaped nest to lay her eggs and protect her spiderlings. So, though she is an air breathing creature, almost her entire life is spent underwater.