| Autor: |
Girndt A; Evolutionary Biology, Max Planck Institute for Ornithology, Seewiesen, Germany. a.girndt@gmail.com.; Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot, United Kingdom. a.girndt@gmail.com.; International Max-Planck Research School (IMPRS) for Organismal Biology, University of Konstanz, Konstanz, Germany. a.girndt@gmail.com., Chng CWT; Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot, United Kingdom., Burke T; Department of Animal and Plant Sciences, University of Sheffield, Sheffield, United Kingdom., Schroeder J; Evolutionary Biology, Max Planck Institute for Ornithology, Seewiesen, Germany.; Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot, United Kingdom. |
| Abstrakt: |
Extra-pair paternity is the result of copulation between a female and a male other than her social partner. In socially monogamous birds, old males are most likely to sire extra-pair offspring. The male manipulation and female choice hypotheses predict that age-specific male mating behaviour could explain this old-over-young male advantage. These hypotheses have been difficult to test because copulations and the individuals involved are hard to observe. Here, we studied the mating behaviour and pairing contexts of captive house sparrows, Passer domesticus. Our set-up mimicked the complex social environment experienced by wild house sparrows. We found that middle-aged males, which would be considered old in natural populations, gained most extra-pair paternity. However, both, female solicitation behaviour and subsequent extra-pair matings were not associated with male age. Further, copulations were more likely when solicited by females than when initiated by males (i.e. unsolicited copulations). Male initiated within-pair copulations were more common than male initiated extra-pair copulations. To conclude, our results did not support either hypothesis regarding age-specific male mating behaviour. Instead, female choice, independent of male age, governed copulation success, especially in an extra-pair context. Post-copulatory mechanisms might determine why older males sire more extra-pair offspring. |
