Ecological Relationships Among Parasites and the Practice of Biological Control1

Abstract

Manipulation of the abundance and distribution of natural enemies is the fundamental basis of biological control. Whether a classical biological control or conservation-augmentation program is being conducted, the database for identifying “ideal” natural enemies is limited. A literature survey of selected host-parasite studies involving, in part, comparisons utilizing ecological indices, suggested that parasite communities are not random assortments of species but are “structured” in terms of life history attributes and habitat stability. Thus, patterns in the composition of parasite communities may provide a framework for selecting suitable biological control agents. However, the ecological indices generally considered—species richness, diversity, evenness, niche breadth, and niche overlap—may have a very limited application in the implementation of biological control. Recommendations involving autecological and synecological studies of parasite communities are presented for contributing relevant data in biological control programs.