If you need an accessible version of this item please contact JSTOR User Support

The Diversity of Parasites

Robert Poulin and Serge Morand
The Quarterly Review of Biology
Vol. 75, No. 3 (Sep., 2000), pp. 277-293
Stable URL: http://www.jstor.org/stable/2665190
Page Count: 17
  • Download PDF
  • Cite this Item

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If you need an accessible version of this item please contact JSTOR User Support
The Diversity of Parasites
Preview not available

Abstract

Parasitism is one of the most successful modes of life displayed by living organisms, as measured by how often it evolved and how many parasitic species are presently in existence. Studying the diversity of parasites is particularly relevant because sympatric diversification may be important in some parasite taxa, and because of the opportunity for independent tests of evolutionary hypotheses in the many separate lineages in which parasitism evolved. Our incomplete knowledge of existing parasite species-the result of a range of phenomena that includes inadequate sampling effort or the lumping of different cryptic species under one name-is not always a major obstacle for the study of parasite diversity. Patterns in the diversity of parasites may be associated with either host or parasite characteristics. The distribution of parasite diversity among host taxa does not simply reflect the species diversity of the host taxa themselves; life history and ecological traits of hosts appear to play important roles. These may determine the likelihood that hosts are colonized by parasite species over evolutionary time. It is not yet clear whether some host traits also favor intrahost speciation and diversification of parasites, and the formation of new parasite species. Certain features of parasites may also be associated with speciation and diversification. Only parasite body size has received much attention; the patterns observed are not greatly different from those of free-living species, with small-bodied parasite taxa being more speciose than related large-bodied taxa. Epidemiological parameters such as the basic reproductive rate of parasites, or R0, can also generate predictions regarding the distribution or evolution of parasite diversity. For instance, parasite taxa characterized by high R0 values may be more speciose than related taxa with lower values of R0; such predictions remain untested. Large-scale biogeographical patterns of diversity have only been well studied for metazoan parasites of marine fish; for these parasites, latitudinal patterns can be explained by effects of temperature on speciation rates and epidemiological variables, though other causes are possible. The emphasis for future research must shift from pattern description to the elucidation of the processes responsible for the structure and diversity of parasite faunas. A better integration of ecological and historical (or phylogenetic) approaches to the study of parasite diversity should make this objective possible.

Page Thumbnails

  • Thumbnail: Page 
277
    277
  • Thumbnail: Page 
278
    278
  • Thumbnail: Page 
279
    279
  • Thumbnail: Page 
280
    280
  • Thumbnail: Page 
281
    281
  • Thumbnail: Page 
282
    282
  • Thumbnail: Page 
283
    283
  • Thumbnail: Page 
284
    284
  • Thumbnail: Page 
285
    285
  • Thumbnail: Page 
286
    286
  • Thumbnail: Page 
287
    287
  • Thumbnail: Page 
288
    288
  • Thumbnail: Page 
289
    289
  • Thumbnail: Page 
290
    290
  • Thumbnail: Page 
291
    291
  • Thumbnail: Page 
292
    292
  • Thumbnail: Page 
293
    293