HOST-PARASITE PHYLOGENIES AND COSPECIATION. IN: COEVOLUTIONARY ECOLOGY OF BIRDS AND THEIR PARASITES

Authors: Hoberg, Eric; BROOKS DANIEL R - DEPT ZOOLOGY,UNIV TORONTO; SIEGEL-CAUSEY DO - STATE MUSEUM,UNIV NEBRSKA

Submitted to: Coevolutionary Ecology of Birds & Their Parasites
Publication Type: Book / Chapter
Publication Acceptance Date: 1/5/1995
Publication Date: N/A
Citation: N/A

Interpretive Summary: A rich body of empirical studies has been summarized over the last century indicating narrowly-defined distributions for mallophagan, cestode and other parasites in avian hosts. The methodologies are now present, e.g., the application of Brooks Parsimony Analysis, to evaluate the patterns of association that have been described. The missing facets for a broad-based comparative, coevolutionary research program reside in the paucity of phylogenetic studies of avian taxa and their parasites. However, at this seminal stage it is apparent that evolution of host-parasite systems is not limited to a single mechanistic explanation (e.g., the assumption of strict cospeciation, and generally archaic associations). Rather, coevolution among avian hosts and their parasites is a richly complex interaction of phylogenetic history, temporal association, and ecological factors which must be recognized and integrated in the development of causal explanations. Only then can there be a critical test of the validity and universality of the paradigm of parasite-host coevolution.

Technical Abstract: The distributions of parasites in avian and other vertebrate taxa are historically constrained by genealogical and ecological as- sociations which can be examined within a phylogenetic context. This framework allows us to examine the origin, temporal con- tinuity and distribution of a parasite-host assemblage with respect to alternative, but not mutually exclusive, hypotheses for coevolution or colonization. Macroevolutionary assessments of cospeciation are necessary to define limits of associations and determinants of distribution and structure (via strict cospeciation/coadaptation versus colonization) prior to more narrowly defined investigations such as those which focus on the phenomenological aspects of reciprocal adaptation. Establishment of the phylogenetic hierarchies and patterns involved becomes a foundation to assess hypotheses for resource tracking models, reciprocal cospeciation in host-specificity, the role of para- sites in sexual selection and coadaptational, arms race hypo- theses. These latter only address relationships after their origins, do not recognize the temporal aspect of an association, and focus in a non-dimensional framework. Conversely, macro- evolutionary approaches can address the origin, maintenance and radiation of faunas through time. Thus we would argue that coevolutionary analyses are requisite to and the initial step in examining host-parasite interactions, biogeography and ecology at any level.