Institute of Biological and Environmental Sciences, School of Biological Sciences, Zoology Building, University of Aberdeen, Tillydrone Avenue, Aberdeen AB24 2TZ, UK.
Proc Biol Sci. 2012 Oct 7;279(1744):4078-86. doi: 10.1098/rspb.2012.1139. Epub 2012 Aug 8.
Numerous studies have tested for indirect selection on female extra-pair reproduction (EPR) by quantifying whether extra-pair young (EPY) are fitter than their within-pair young (WPY) maternal half-siblings. In contrast, the hypothesis that offspring of EPY and WPY (rather than the EPY and WPY themselves) differ in fitness has not been tested, even though inter-generational effects of parental extra-pair status on offspring fitness could alter the magnitude and direction of indirect selection on EPR. We tested whether offspring of EPY song sparrows, Melospiza melodia, were more likely to recruit or produce hatched or recruited offspring over their lifetimes than offspring of WPY. Hatchlings with one or two EPY parents were more likely to recruit and produce hatched offspring than hatchlings with two WPY parents. Furthermore, these relationships differed between maternal versus paternal extra-pair status. Hatchlings with EPY fathers were more likely to recruit and produce offspring than hatchlings with WPY fathers. In contrast, hatchlings with EPY mothers were as likely to recruit as hatchlings with WPY mothers and tended to be less likely to produce recruited offspring. Depending on the causal genetic and environmental mechanisms, such conflicting inter-generational relationships between parental extra-pair status and offspring fitness could substantially influence the evolutionary dynamics of EPR.
许多研究通过量化研究证明了对雌性的选择性间接选择，以检验是否存在与其配对的幼鸟（WPY）相比，外部交配幼鸟（EPR）具有更高的适应度。然而，即使父母的外部交配地位对后代适应度的代际影响可能会改变对 EPR 的间接选择的幅度和方向，但对于 EPY 和 WPY 的后代（而不是 EPY 和 WPY 本身）在适应度上存在差异的假设尚未得到检验。我们检验了 EP 歌雀（Melospiza melodia）的 EPR 后代是否比 WPY 后代更有可能在一生中招募或产生孵化或招募的后代。与具有两个 WPY 父母的雏鸟相比，具有一个或两个 EPY 父母的雏鸟更有可能招募和产生孵化的后代。此外，这些关系在母体与父体的外部交配状态之间存在差异。具有 EPY 父亲的雏鸟比具有 WPY 父亲的雏鸟更有可能招募和产生后代。相反，具有 EPY 母亲的雏鸟与具有 WPY 母亲的雏鸟一样有可能招募，而且不太可能产生被招募的后代。根据因果遗传和环境机制，这种父母外部交配地位与后代适应度之间的相互矛盾的代际关系可能会对 EPR 的进化动态产生重大影响。
