Tracking the origins of lice, haemosporidian parasites and feather mites of the Galápagos flycatcher (Myiarchus magnirostris)

Aim:To discover the origins of the lice, haemosporidian parasites and feather mites found on or in Galápagos flycatchers (Myiarchus magnirostris), by testing whether they colonized the islands with the ancestors of M. magnirostris or if they were acquired by M. magnirostris after its arrival in the Galápagos Islands.

Location: The Galápagos Islands (Ecuador) and north‐western Costa Rica.

Methods: We collected lice, feather mites and blood samples from M. magnirostris on seven of the Galápagos Islands (n = 254), and from its continental sister species, M. tyrannulus, in Costa Rica (n = 74), and identified them to species level using traditional taxonomy and DNA sequencing.

Results:The blood parasites from the two bird species were different: Plasmodium was found only in M. tyrannulus, while a few individuals of M. magnirostris were infected by Haemoproteus multipigmentatus from Galápagos doves (Zenaida galapagoensis). Myiarchus tyrannulus was parasitized by three louse species, two of which (Ricinus marginatus and Menacanthus distinctus) were also found on Myiarchus magnirostris. We also collected one louse specimen from M. magnirostris, which was identified as Brueelia interposita, a species commonly found on finches and yellow warblers from the Galápagos, but never recorded on M. tyrannulus. The richness of mite species was lower for M. magnirostris than for M. tyrannulus; all mite species or genera from M. magnirostris were also sampled on M. tyrannulus, but M. tyrannulus had two additional mite species.

Main conclusions: Our results revealed that two of the louse and three of the mite species we found on M. magnirostris are likely to have come to the archipelago with these birds’ colonizing ancestors, but that one louse and one haemosporidian species were acquired from the Galápagos bird community after the arrival of the M. magnirostris lineage. We also confirmed that, for closely related hosts, island mite richness was lower than on the continent.