MHC diversity, malaria and lifetime reproductive success in collared flycatchers.

Major histocompatibility complex (MHC) genes encode proteins involved in the recognition of parasite-derived antigens. Their extreme polymorphism is presumed to be driven by co-evolution with parasites. Host-parasite co-evolution was also hypothesized to optimize within-individual MHC diversity at the intermediate level.

Heritable variation in maternal yolk hormone transfer in a wild bird population.

Differential reproductive investment by the mother can critically influence offspring development and phenotype, and strong selection is therefore expected to act on such maternal effects. Although a genetic basis is a prerequisite for phenotypic traits to respond to selection and thus to evolve, we still know very little about the extent of heritable variation in maternal effects in natural populations. Here, we present the first estimates of intrafemale repeatability across breeding seasons and estimates of heritability of hormone-mediated maternal effects in a wild population of collared flycatchers (Ficedula albicollis).

Nestling immune response to phytohaemagglutinin is not heritable in collared flycatchers.

The response to intradermally injected phytohaemagglutinin (PHA-response) is a commonly used quantification of avian immunocompetence (the ability to resist pathogens). Parasite-mediated sexual selection requires heritable immunocompetence, but evidence for heritability of PHA-response in birds largely stems from full-sib comparisons. Using an animal model approach, we quantified the narrow-sense heritability of PHA-response in 1626 collared flycatcher (Ficedula albicollis) nestlings from 332 families, most of which were cross-fostered.