title: Variation in parent-offspring kinship in socially monogamous systems with extra-pair reproduction and inbreeding.
abstract: Female extra-pair reproduction in socially monogamous systems is predicted to cause cuckolded socially-paired males to conditionally reduce paternal care, causing selection against extra-pair reproduction and underlying polyandry. However, existing models and empirical studies have not explicitly considered that cuckolded males might be related to their socially-paired female and/or to her extra-pair mate, and therefore be related to extra-pair offspring that they did not sire but could rear. Selection against paternal care, and hence against extra-pair reproduction, might then be weakened. We derive metrics that quantify allele-sharing between within-pair and extra-pair offspring and their mother and her socially-paired male in terms of coefficients of kinship and inbreeding. We use song sparrow (Melospiza melodia) paternity and pedigree data to quantify these metrics, and thereby quantify the joint effects of extra-pair reproduction and inbreeding on a brood's total allelic value to its socially-paired parents. Cuckolded male song sparrows were almost always detectably related to extra-pair offspring they reared. Consequently, although brood allelic value decreased substantially following female extra-pair reproduction, this decrease was reduced by within-pair and extra-pair reproduction among relatives. Such complex variation in kinship within nuclear families should be incorporated into models considering coevolutionary dynamics of extra-pair reproduction, parental care, and inbreeding.
authors.affiliation: Institute of Biological and Environmental Sciences, School of Biological Sciences, Zoology Building, University of Aberdeen, Tillydrone Avenue, Aberdeen, AB24 2TZ, Scotland. jane.reid@abdn.ac.uk.
authors.forename: Jane M
authors.initials: JM
authors.lastname: Reid
authors.affiliation: Institute of Biological and Environmental Sciences, School of Biological Sciences, Zoology Building, University of Aberdeen, Tillydrone Avenue, Aberdeen, AB24 2TZ, Scotland.
authors.forename: Greta
authors.initials: G
authors.lastname: Bocedi
authors.affiliation: Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.
authors.forename: Pirmin
authors.initials: P
authors.lastname: Nietlisbach
authors.affiliation: Institute of Biological and Environmental Sciences, School of Biological Sciences, Zoology Building, University of Aberdeen, Tillydrone Avenue, Aberdeen, AB24 2TZ, Scotland.
authors.forename: A Bradley
authors.initials: AB
authors.lastname: Duthie
authors.affiliation: Institute of Biological and Environmental Sciences, School of Biological Sciences, Zoology Building, University of Aberdeen, Tillydrone Avenue, Aberdeen, AB24 2TZ, Scotland.
authors.forename: Matthew E
authors.initials: ME
authors.lastname: Wolak
authors.affiliation: Department of Forest and Conservation Sciences, 2424 Main Mall, University of British Columbia, Vancouver BC, Canada, V6T 1Z4.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Gow
authors.affiliation: Department of Forest and Conservation Sciences, 2424 Main Mall, University of British Columbia, Vancouver BC, Canada, V6T 1Z4.
authors.forename: Peter
authors.initials: P
authors.lastname: Arcese
mesh_terms: D000818:Animals; D005260:Female; D007178:Inbreeding; D008297:Male; D010375:Pedigree; D012098:Reproduction; D012726:Sexual Behavior, Animal; D020308:Songbirds / Q000235:genetics / Q000502:physiology*
keywords: Cuckoldry; paternal investment; paternity; pedigree; polyandry; relatedness; sexual conflict