I'll begin this new blog with the story of the Diving Bell Spider, from the New York Times. Magnificent.
The water spiders occasionally venture above the surface to take in oxygen, but as researchers now report in The Journal of Experimental Biology, they can safely stay underwater for a day or more at a time, longer than previously thought.
The spider weaves a silk bubble, known as a diving bell, on underwater vegetation. It uses this bell to extract oxygen from water, said the study’s first author, Roger Seymour, a biologist at the University of Adelaide in Australia.
The bell acts as a gill, and pulls in dissolved oxygen from fresh water. Although this was previously known, Dr. Seymour and his colleague Stefan K. Hetz of Humboldt University in Berlin, used a device to measure exact changes in the bell’s oxygen levels for the first time.
Even in warm, stagnant water, the bell extracts oxygen that the spiders can rely on, they found.
“The value of staying underwater is that you don’t scare the prey away,” Dr. Seymour said. “And if you go to the surface often you might alert a bird.”
Water spiders trap insects and small fish in their bell, just as terrestrial spiders capture insects in their webs. They have the ability to sense when something hits their underwater web, and they dash out to paralyze the prey before pulling it into the bell, Dr. Seymour said.
Female spiders lay eggs within the bell, and hatched spiders build bells of their own.