The Ecological Significance of Parasitic Crustaceans

Despite that aquatic parasite diversity and abundance likely surpasses that of terrestrial parasites, our understanding of aquatic parasites lags far behind our knowledge of terrestrial parasites. This is undoubtedly attributable to our being terrestrial primates and the associated logistical challenges of studying most aquatic environments. However, with improving technology that allows for more extended exploration of aquatic environments and the continued maturation of host-parasite ecology and functional biodiversity as fields of inquiry, our understanding of parasitic crustaceans is rapidly extending beyond identification and description of life cycles to describing the role of parasites in ecosystems. Both field and laboratory studies have demonstrated that parasitic organisms play critical roles at the individual, population and community levels. In this chapter, we explore these roles for parasitic isopods and copepods in particular and highlight recent studies that employ current methodologies in ecological research such as molecular and stable isotope analyses. This chapter should demonstrate to readers that there are still far more questions than answers about the role of parasitic Crustacea in aquatic systems, but based on what we know today, we can say they are likely one of the most critical players in aquatic ecosystem dynamics.