PHYSIOLOGY OF TERRESTRIAL ISOPODS

1. This article reviews the physiology of oniscidean isopods, a group of terrestrial crustaceans known commonly as woodlice or sowbugs. 2. The oniscideans are represented by several hundred species in 34 families and occupy habitats ranging from sea beach to woodland, grassland and desert. 3. The widespread interest in woodlice stems, in part, from their evolutionary transition from marine to terrestrial habit directly over sea beaches. Representative stages of this evolutionary transition are extant within the oniscidean group. 4. Water and water relations have featured prominently in the accession to land by woodlice; consequently, these topics have been the focus of much historical and recent research work. The present review builds on a strong foundation of behavioural research on water relations and explores the evolutionary success of these unique crustaceans from a physiological point of view, emphasizing recently published work. 5. Topics include gas exchange and effects on VO2, marsupial adaptations, water-vapour absorption, ammonia excretion, moulting and its neuroendocrine control, nutrition and osmotic regulation.