Evolution of parasite island syndromes without long-term host population isolation: parasite dynamics in Macaronesian blackcaps Sylvia atricapilla

Authors

  • Antón Pérez-Rodríguez,

    Corresponding author
    1. Departamento de Zoología y Antropología Física, Universidad Complutense de Madrid, Madrid, Spain
    • Correspondence: Antón Pérez-Rodríguez, Zoologia y Antropologia Fisica, Universidad Complutense de Madrid, Calle Jose Antonio Novais, 2, Madrid 28040, Spain.

      E-mail: adperez@bio.ucm.es

    Search for more papers by this author
  • Álvaro Ramírez,

    1. Departamento de Zoología y Antropología Física, Universidad Complutense de Madrid, Madrid, Spain
    Search for more papers by this author
  • David S. Richardson,

    1. Centre for Ecology, Evolution and Conservation, School of Biological Sciences, University of East Anglia, Norwich, UK
    Search for more papers by this author
  • Javier Pérez-Tris

    1. Departamento de Zoología y Antropología Física, Universidad Complutense de Madrid, Madrid, Spain
    Search for more papers by this author

  • Editor: Shai Meiri

Abstract

Aim

The study of parasite biogeography on islands is important for our understanding of both the processes involved in the evolution of parasite assemblages worldwide and the ecology and conservation of insular communities. By studying the haemosporidian blood parasites of a bird that has recently colonized a number of oceanic islands, we were able to test hypotheses relating to the processes of parasite colonization and community assembly prior to the permanent isolation of host species on islands.

Location

The Atlantic Ocean archipelagos of Madeira and the Canary Islands.

Methods

We used cytochrome b DNA sequences to determine the prevalence and richness of parasites of the genera Haemoproteus, Plasmodium and Leucocytozoon in blackcaps, Sylvia atricapilla, a widespread passerine that colonized these archipelagos during the Last Glacial Maximum. We compared insular blackcap parasite assemblages with those observed in 37 blackcap populations sampled on mainland Europe.

Results

The insular parasite assemblage was impoverished, containing c. 10% of the parasites found on the continent. None of the parasites observed on the islands were blackcap specific. Some of the observed parasites appear to have switched from blackcaps to other Macaronesian host species, whereas others were of Afrotropical origin and were acquired after blackcaps colonized the islands. The prevalence of parasites in the island populations of blackcaps was lower than in mainland blackcap populations and parasite richness decreased with increasing island distance to the continent.

Main conclusions

Macaronesian blackcaps do not face the strong parasite load encountered by their mainland counterparts despite the fact that blackcap migration from the continent may directly transport mainland blackcap parasites to the islands. This supports the idea that normal mainland host–parasite associations are compromised on islands and that parasite island syndromes (low richness, frequent host-switching and reduced specialization) evolve even before insular host populations become completely isolated from their mainland counterparts.

Ancillary