Résumé
This chapter argues that parasite-induced changes in host phenotypes can have a dramatic impact on the community structure of their free-living hosts. It begins with a review of host-manipulation literature, illustrating how parasites can modify their host phenotypes in dramatic ways. It then considers two generic examples of host manipulation: parasite-induced susceptibility to predation (PISP) and parasite-induced castration (PIC), and develops simple population-dynamical models of the consequences of PISP and PIC on communities (host plus two predators for PISP, host plus competitor for PIC). Finally, the chapter highlights how the simple model results are likely to have parallels in a range of empirical systems, offering an agenda for future theoretical and empirical research.