EVOLUTION OF TICKS

Evolutionary patterns in ticks have traditionally been cast in terms o f host associations. Largely untested assumptions of cospeciation and observations of current host associations are used to estimate the age of different taxa. Several recent phylogenetic studies of supraspecif ic relationships in ticks, based on both morphological and DNA-sequenc e data, allow the first rigorous testing of these assumptions. Reanaly sis of patterns of tick-host associations suggests that the perception of host specificity in ticks may be an artifact of incomplete samplin g. An analysis of tick-host and -habitat associations and biogeographi cal patterns, in the context of the newly derived phylogenies, suggest s that much of the existing host-association patterns may be explained as artifacts of biogeography and ecological specificity.