sandhoppers) and decapods (crabs, shrimp, etc.). Terrestrial isopods play an important role in many tropical and temperate ecosystems by aiding in the decomposition of plant material through mechanical and chemical means, and by enhancing the activity of microbes. Macro-detritivores, including terrestrial isopods, are absent from arctic and sub-arctic regions, but have the potential to expand their range with increased temperatures in high latitudes. The woodlice, suborder Oniscidea, are the most successful group of terrestrial crustaceans and show various adaptations for life on land. They are subject to evaporation, especially from their ventral area, and as they do not have a waxy cuticle, they need to conserve water, often living in a humid environment and sheltering under stones, bark, debris or leaf litter. Desert species are usually nocturnal, spending the day in a burrow and emerging at night. Moisture is achieved through food sources or by drinking, and some species can form their paired uropodal appendages into a tube and funnel water from dewdrops onto their pleopods. In many taxa, the respiratory structures on the endopods are internal, with a spiracle and pseudotrachaea, which resemble lungs. In others, the endopod is folded inside the adjoining exopod (outer branch of the pleopod). Both these arrangements help to prevent evaporation from the respiratory surfaces. Many species can roll themselves into a ball, a behaviour used in defence that also conserves moisture. Members of the families Ligiidae and Tylidae, commonly known as rock lice or sea slaters, are the least specialised of the woodlice for life on land. They inhabit the splash zone on rocky shores, jetties and pilings, may hide under debris washed up on the shore and can swim if immersed in water. As pets Many species have become popular as pets in the last few decades. With this popularity new variants, or morphs, have been selectively bred : for example Porcellionides pruinosus which are among the most popular and beginner-friendly have been bred to appear in "powder blue", "powder orange", and "powder purple". For enthusiasts, the most sought after species comes from Thailand, the Cubaris sp. Rubber Ducky. Many people keep isopods with their reptiles and amphibians as a "cleanup crew" in bioactive vivaria, whilst others keep them by themselves for their interesting activity and ease of care. References External links World List of Marine Freshwater and Terrestrial Isopod Crustaceans Malacostraca Extant Pennsylvanian first appearances Taxa named by Pierre André Latreille