Amazing Design: Scuba Spiders

Spider silk, renowned for its strength and elasticity, has uses beyond the common spider web, reports National Geographic News on research from the University of Bern in Switzerland. A unique type of spider that spends its entire life underwater uses silk to spin personal “scuba tanks” for various purposes, including oxygen supply.

“The water spider’s air bell is in some ways working like an external lung,” explained Michael Taborsky, one of the study’s authors. The creatures use short hairs on their abdomens and legs to trap air bubbles from pond surfaces, which then they deposit in the bells. The membrane formed by the silk “allows oxygen to diffuse in from the water and carbon dioxide to diffuse out,” allowing the spiders to remain submerged for lengthy periods of time.

Furthermore, the spiders apparently have the means to keep close tabs on the concentration of carbon dioxide inside their bells. In an experiment, the research team replaced the gas in the bells of a number of spiders with pure oxygen, pure carbon dioxide, or ordinary air to observe the effects on the spiders’ behavior.

When spiders had their bells filled with pure carbon dioxide, they surfaced more frequently and increased “bell-building behavior” until the oxygen levels returned to normal. This confirmed that the spiders both monitor the quality of their bells’ atmosphere and use the bells as external lungs.

Additionally, the spiders use the bells as protection from terrestrial predators and as a safe place to lay eggs and raise offspring, and spiders may feed or breed inside the bells.

How’s that for incredible design? We certainly don’t think these spiders stumbled upon such complicated behavior by chance!

The research will be published in the October issue of the Journal of Experimental Zoology Part A: Ecological Genetics and Physiology.