Geographic and individual variation in haematozoan infections in the greenfinch, Carduelis chloris

Abstract

Within populations, there were no consistent differences in prevalence between sexes or between older age-classes, but prevalence was significantly lower among yearling birds (<5 months old) in one population. Individual heterozygosity using five polymorphic protein coding loci, did not differ between infected and noninfected birds, but significant differences in prevalence between Fennoscandian (high), central European (low), and Iberian (high) populations is consistent with the hypothesis that destruction of natural habitats has led to a significant decline of vector populations in C Europe. Given the high among-populations variation in prevalence, results point to the need to consider the possibility of sampling bias in studies that seek to test, using avian blood parasites, the Hamilton-Zuk hypothesis that parasite resistance might be the target of female choice and drive the evolution of bright plumage and elaborate ornamentation. -from Authors