Physiological Topics in Annelid Regeneration and Related Processes

The ability of many species of annelid worms to regenerate lost structures has attracted researchers from many fields for over two centuries. Since regeneration is considered a post-embryonic developmental process, its study has often been framed within the field of Developmental Biology. Many aspects of regeneration, particularly those dealing with regulation, integration, and resource allocation, are however closely linked with topics traditionally studied by the field of Physiology. In this chapter, we provide a basic outline of structure regeneration and related phenomena in Annelida and offer brief summaries on what is currently known about their neurohormonal control, the roles played by inputs from the nervous system, and the associated patterns of cell proliferation and metabolic changes during regeneration; we close by discussing the metabolic and evolutionary costs of repair. Throughout the chapter, it should be made evident that development and physiology are tightly interwoven in the process of annelid regeneration, 2and only an integrative approach can help us to further our understanding of this extraordinary phenomenon.