How Do Spiders Breathe?
WouterSpiders breathe through their trachea and lungs. Most arachnids have at least one pair of book lungs and some have two. The book lungs are the most important for gas exchange. They are thin air filled plates with slits that allow oxygen to pass through the plates. The slits can never close completely. This allows for maximal gas exchange with the environment.
The spider trachea begins at small openings on the underside of the spider’s exoskeleton. The trachea then branch out through the body. The trachea are lined with a hard substance called chitin. As the trachea move through the body, carbon dioxide is diffused into the air. The trachea are located at the posterior end of the spider.
A spider’s trachea is a complex network of tubes that extend throughout the spider’s body. Some spiders have a single spiracle on their abdomen, while others have two or more. Some arachnids have trachea and book lungs in one system, while others have trachea and gills.
Argyroneta aquatica is a 10-millimeter-long spider that lives underwater. It produces a bubble of air that it deposits into a silk air tank. The spider then uses the bubble to stay under the water for up to 24 hours.
Professor Roger Seymour has studied the spider’s air bubble. He found that the bubble behaves like a gill. It collapses when nitrogen concentrations increase in the air bubble.
Scientists believe that the trachea is an evolution of the book lungs. While both systems are found in arachnids, the trachea is a more recent feature.
