Parasites represent ideal models for unravelling the origins of island biodiversity. Here, we examined patterns of genetic diversity and structure of seabird ticks within the Cape Verde Archipelago. Contrary to our expectations, several tick lineages from worldwide locations co-occur on these islands. Although specific tick-seabird associations within islands suggest secondary post-colonisation adaptation to particular seabird species, most local diversity could be explained by repeated trans-oceanic colonisation events. This study demonstrates the unappreciated frequency at which seabirds may disperse parasites over extreme spatial scales and, in doing so, their potential to alter the evolutionary ecology and epidemiology of these organisms.

Reference work: Gómez-Díaz, E., Morris-Pocock, J., González-Solís, J., McCoy, D. Trans-oceanic host dispersal explains seabird tick diversity on Cape Verde islands. 2012. Biology Letters. Ahead of Print doi:10.1098/rsbl.2012.0179