Cospeciation has been observed multiple times between parasites and their hosts. Here we compare the phylogeny of 2 different groups of chewing lice (Phthiraptera), one known for being host specific (Amblycera: Myrsidea) and one known for including many generalist species (Ischnocera: Brueelia-complex, specifically Guimaraesiella and Priceiella) with that of their songbird hosts (Passeriformes), which are participants in mixed-species feeding flocks in South China. Using event- (Jane) and distance-based (ParaFit) analyses we found that both groups of lice have phylogenies that are more similar than by chance to those of their hosts. However, more cospeciation and host-switching events were inferred for the Myrsidea data set, whereas more duplication events and losses were inferred for the Brueelia-complex data set. Even though these louse groups are found on roughly the same host species, the differences in sorting events may be linked to the different modes of dispersal. Whereas both groups transfer by direct contact, phoresy is recorded only in lice belonging to the Brueelia-complex.
