SNAIL TREMATODE INTERACTIONS AND PARASITE COMMUNITY DYNAMICS IN AQUATIC SYSTEMS - A REVIEW

The study of parasite communities has traditionally focussed on helminth communities in vertebrate hosts. However, the literature reveals a substantial body of information which shows that infra- and component trematode communities in snails frequently are highly structured and very dynamic in character. A variety of forces, both internal and external to the snail, affect the manner in which these communities are organized and function. While snail-trematode and trematode-trematode interactions are variable, it appears that some generalizations are beginning to emerge. It is clear that a combination of host immunity, resource partitioning within infracommunities, patch dynamics associated with parasite transmission, temporal factors involved with snail ontogeny, the presence of autogenic and allogenic parasite species within a given habitat, and the potential for interspecific antagonism, collectively, operate to create the special nature of trematode communities in molluscan intermediate hosts.