Analytical approaches to measuring cospeciation of host and parasites: through a glass, darkly

Studies of cophylogenetic associations between hosts and parasites have bec ome increasingly common. Historically, congruence between host and parasite phylogenies has been seen as evidence for cospeciation. Analyses of such c oevolutionary relationships, however, are made extremely difficult by the c omplex interplay of cospeciation. host switching, sorting (extinction), dup lication (intrahost speciation) and inertia (lack of parasite speciation) e vents, all of which may produce incongruence between host and parasite phyl ogenies. Here we review several methods of analysing cospeciation. We illus trate these methods with an example from a Procellariiformes (seabird) and chewing louse (Halipeurus) association. (C) 2001 Australian Society for Par asitology Inc. Published by Elsevier Science Ltd. All rights reserved.