Host preference of a temperate mistletoe: Disproportional infection on three co‐occurring host species influenced by differential success

The mistletoeTristerix verticillatus(Loranthaceae) parasitizes within a small area of the Yerba Loca Nature Sanctuary near Santiago, Chile, three co‐occurring hosts:Schinus montanus(Anacardiaceae),Fabiana imbricata(Solanaceae) andBerberis montana(Berberidaceae). Previous studies suggest thatT. verticillatusmay be favoured when parasitizingS. montanusrelative to the other two host species. We hypothesize that infection ofS. montanusis not proportional to its local abundance or appearance, thatS. montanusis more intensively parasitized than other available hosts, and that host provenance is a determinant of the fate of the infecting seed. We compare the incidence of infection ofT. verticillatusin relation to local availability and appearance variables, and the intensity of infection ofT. verticillatus, on the three co‐occurring host species. We then test the effects of host provenance on mistletoe seed establishment success with a seed cross inoculation experiment varying the donor and receptor hosts. Finally, we test whether there are differences in establishment success between manually processed seeds and seeds defecated by the avian disperserMimus thenca(Passeriformes: Mimidae). Our results show that the three hosts have an aggregated spatial distribution.Schinus montanuswas parasitized at a higher rate than expected by its local availability and appearance, and inoculated seeds showed differential development depending on the origin of the seeds: seeds fromT. verticillatusparasitizingS. montanusinoculated toS. montanustwigs showed higher germination and lower mortality than seeds fromT. verticillatusparasitizingF. imbricatainoculated toS. montanustwigs. Furthermore, seeds defecated by the avian disperser,M. thenca, had higher adherence and reduced mortality when compared to manually processed seeds. The disproportional host infection found is discussed in terms of the differential establishment of mistletoe seeds, morphological characteristics of hosts and the behaviour of dispersing birds.