Are lice good proxies for host history? A comparative analysis of the Australian magpie, Gymnorhina tibicen, and two species of feather louse

Parasites have been recently advocated as useful proxies for unravelling a complex evolutionary history of a host. In the present study, two species of feather lice, Brueelia semiannulata and Philopterus sp. were analysed for mitochondrial variation and compared to mitochondrial and nuclear variation in their host, the Australian magpie Gymnorhina tibicen. Phylogenies constructed using maximum likelihood methods revealed geographic structuring for both species of feather lice and host. Our genetic analysis shows concordance of east–west structure between host and Philopterus sp. indicating that it is an informative proxy for host history. Analysis of the Philopterus sp. phylogeny also suggested cryptic structuring within the eastern magpie population that had not been previously realized through genetic analysis of the host. B. semiannulata however, did not show congruent phylogeographic structuring with the host. Rather than showing an east–west split between lineages, the phylogeny of B. semiannulata showed north–south geographic structuring. It is postulated that this incongruence may be due to ecological habitat differences and/or the dispersal ability of B. semiannulata.