Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: March 15, 2012
Publication Date: N/A
The focus in this chapter is on those groups of protists that are pathogenic to their insect hosts, although some basic data necessary for the identification of non-pathogenic taxa are provided. Protist-insect symbiotic relationships reflect the full range of possible interactions, from commensalism, whereby the host simply provides a spatial niche for the life-cycle of the protist, to mutualistic relationships where the protist and host are each essential for the survival of the other, to parasitism, interactions in which the protist is truly pathogenic to the insect host. Although any tissue or organ of insects may be infected, the various groups of protists characteristically infect specific tissues in insect larval stages and adults. Amoebae and flagellates generally target parts of the digestive tract (pharynx, salivary glands, proventriculus, midgut, Malpighian tubules). Apicomplexa, are intracellular and epicellular, usually infecting gut tissues, Malpighian tubules and fat bodies, but also have forms that develop in the hemocoel. Microsporidia are strictly intracellular and their representatives can be tissue specific or systemic, occurring in nearly all body tissues. The ciliates that occur in insects appear to be restricted to the hemocoel and to the gut lumen. Because the Microsporidia are by far the most widely studied of the entomopathogenic protists, most of the methods and techniques described here were drawn from research on this group.