Biogeography of haemo- and ectoparasites of an arid-land bird, the Trumpeter finch

Abstract

The study of biogeographical patterns is basic to understand the processes that rule the distribution of parasites and to understand the influence that they have on host population dynamics. We tested (i) whether island dwelling host populations have lower parasite richness and higher prevalence than the mainland one; and, (ii) whether an expanding host population undergoes both lower parasite richness and prevalence than the source one. For these purposes, we studied the parasite fauna (haemo- and ectoparasites) of 398 Trumpeter finches (Bucanetes githagineus), an arid-adapted passerine, in three regions, the Canary Islands, south-eastern Iberian Peninsula (continental expanding) and Northwest Africa (mainland, source population). We searched for blood parasites microscopically. We studied feather lice and feather mites by scanning plumage of trapped birds. Whereas we found two haemoparasite species in the mainland/source population, one in the island and two in the expanding population, we found two ectoparasites species in the mainland/source and three both in the island and in the expanding populations. Average and total prevalence of haemoparasites were highest in the mainland/source population. Ectoparasites had the lowest prevalence in the mainland/source population. Thus, we found that blood parasites fit the biogeographical predictions whereas ectoparasites do not.