Different arthropods have different respiratory systems. Some have gills in which the gas exchange takes place, and others have a tracheal respiratory system. Each respiratory system works a little differently.
Only those arthropods that live in water have gills. The gills in these animals work in the same way as the gills of a fish, providing a gas exchange that allows the animals to take in oxygen.
Land arthropods have a system of trachea that are little air ducts that are located throughout the animal's entire body. Arthropods have the ability to open and close these air ducts so they can conserve water when necessary.