Respriation

Arthropods don’t have lungs but they have other ways of getting oxygen through their bodies, by using spiracles, gills, book lungs or even a combination of more then one.

Aquatic arthropods use gills for breathing; as water flows into their bodies the gills draw oxygen out of the water. They also use a movement of the mouth parts and other appendages to keep water flowing into their gills.

Insects, centipedes and millipedes breath through tiny holes along the sides of their thoraxes or abdomens called spiracles. The spiracles then lead to tracheas which transport air though their bodies.

While some chelicerata take air through book lungs, which are a series of folds with in their exoskeleton. Air passes between folds and mixes with the blood and then circulates around the body. Arachnids with book lungs also have tracheas to transport air into their bodies.