title: The colour of paternity: extra-pair paternity in the wild Gouldian finch does not appear to be driven by genetic incompatibility between morphs.
abstract: In socially monogamous species, individuals can use extra-pair paternity and offspring sex allocation as adaptive strategies to ameliorate costs of genetic incompatibility with their partner. Previous studies on domesticated Gouldian finches (Erythrura gouldiae) demonstrated a genetic incompatibility between head colour morphs, the effects of which are more severe in female offspring. Domesticated females use differential sex allocation, and extra-pair paternity with males of compatible head colour, to reduce fitness costs associated with incompatibility in mixed-morph pairings. However, laboratory studies are an oversimplification of the complex ecological factors experienced in the wild and may only reflect the biology of a domesticated species. This study aimed to examine the patterns of parentage and sex ratio bias with respect to colour pairing combinations in a wild population of the Gouldian finch. We utilized a novel PCR assay that allowed us to genotype the morph of offspring before the morph phenotype develops and to explore bias in morph paternity and selection at the nest. Contrary to previous findings in the laboratory, we found no effect of pairing combinations on patterns of extra-pair paternity, offspring sex ratio or selection on morphs in nestlings. In the wild, the effect of morph incompatibility is likely much smaller, or absent, than was observed in the domesticated birds. Furthermore, the previously studied domesticated population is genetically differentiated from the wild population, consistent with the effects of domestication. It is possible that the domestication process fostered the emergence (or enhancement) of incompatibility between colour morphs previously demonstrated in the laboratory.
authors.affiliation: Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia.
authors.forename: P E
authors.identifier: 0000-0002-2057-1973
authors.initials: PE
authors.lastname: Bolton
authors.affiliation: Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia.|Centre for Integrative Ecology, School of Life and Environmental Sciences, Deakin University, Geelong, Vic., Australia.
authors.forename: L A
authors.initials: LA
authors.lastname: Rollins
authors.affiliation: Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Brazill-Boast
authors.affiliation: Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK.
authors.forename: K-W
authors.initials: KW
authors.lastname: Kim
authors.affiliation: Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK.
authors.forename: T
authors.initials: T
authors.lastname: Burke
authors.affiliation: Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia.
authors.forename: S C
authors.initials: SC
authors.lastname: Griffith
mesh_terms: D000818:Animals; D003116:Color; D005260:Female; D046369:Finches; D005838:Genotype; D008297:Male; D010334:Paternity; D010641:Phenotype; D016133:Polymerase Chain Reaction; D012744:Sex Ratio
keywords: Estrildidae; colour polymorphism; domestication; mate choice; polyandry; post-zygotic isolation