Male-Biased Sex of Extra Pair Young in the Socially Monogamous Red-Backed Shrike Lanius collurio

TitleMale-Biased Sex of Extra Pair Young in the Socially Monogamous Red-Backed Shrike Lanius collurio
Publication TypeJournal Article
Year of Publication2008
AuthorsSchwarzová L, Šimek J, Coppack T, Tryjanowski P
JournalActa Ornithologica
Volume43
Issue2
Pagination - 235 - 239
Date Published2008
ISBN Number0001-6454
KeywordsCollurio, Czech Republic, Lanius, Lanius collurio
Abstract

Abstract. Females of many socially monogamous bird species engage in ? or even actively seek ? copulations outside their social pair bond. However, in socially monogamous birds with low breeding abundance, such as the Red-backed Shrike, extra-pair paternity (EPP) was thought to be an exceptional and random incident. Drawing on samples collected in an unusually dense Red-backed Shrike population in the Czech Republic, we show through DNA microsatellite typing that among 65 chicks from 15 nests, 10 individuals (26.5%) had been sired by males other than the nest-attending social mate. All 10 extra pair young were of male sex. In all cases, genetic fathers of extra pair young stemmed from neighbouring territories. Extra pair fathers had significantly longer tarsi than social mates, indicating that female choice was a function of age-class dependent male body size. Our findings support sex allocation theory, which suggests that promiscuous females mating with higher quality males should produce mostly sons.Abstract. Females of many socially monogamous bird species engage in ? or even actively seek ? copulations outside their social pair bond. However, in socially monogamous birds with low breeding abundance, such as the Red-backed Shrike, extra-pair paternity (EPP) was thought to be an exceptional and random incident. Drawing on samples collected in an unusually dense Red-backed Shrike population in the Czech Republic, we show through DNA microsatellite typing that among 65 chicks from 15 nests, 10 individuals (26.5%) had been sired by males other than the nest-attending social mate. All 10 extra pair young were of male sex. In all cases, genetic fathers of extra pair young stemmed from neighbouring territories. Extra pair fathers had significantly longer tarsi than social mates, indicating that female choice was a function of age-class dependent male body size. Our findings support sex allocation theory, which suggests that promiscuous females mating with higher quality males should produce mostly sons.

URLhttp://dx.doi.org/10.3161/000164508X395379
Short TitleActa Ornithologica