Lifjeld JT, Slagsvold T, Ellegren H
Zoological Museum, University of Oslo
Anim Behav. 1997 Jun;53(6):1225-32. doi: 10.1006/anbe.1996.0430.
By making female birds pair successively with different males, and analysing the paternity of the eggs laid, it is possible to examine how a male's success in obtaining fertilizations is determined by the timing of his copulatory access to the female. Such an experiment is reported here with pied flycatchers, Ficedula hypoleucaMate switching was induced at different stages within the female's fertile period by removing the resident male. The paternity of the clutch was analysed by microsatellite DNA typing. Removed males had full paternity in the clutch if they were removed as late as after the second egg was laid (day 1), and they lost all paternity if they were removed more than 1 day before the first egg was fertilized (less than day -2). Male switching during the period day -2 to day 1 always resulted in mixed paternity in the clutch. Males that were paired to the female for only a few (1-3) days during this period achieved on average more than one fertilization per access day, with a peak on day -1. Thus, assuming that the timing of observed pair bonds reflects the timing of each male's copulatory access to the female, the first eggs in the laying sequence were fertilized by inseminations occurring shortly before the time of fertilization, whereas the last eggs were fertilized by inseminations taking place several days prior to their fertilization. Our documentation of the most important period for copulatory access has some important implications for understanding sexual behaviour in this species.
通过让雌鸟先后与不同雄鸟配对，并分析所产蛋的父系情况，就有可能研究雄鸟在获得受精方面的成功是如何由其与雌鸟交配的时间决定的。本文报道了一项针对斑姬鹟（Ficedula hypoleuca）的此类实验。通过移除留驻雄鸟，在雌鸟的排卵期内不同阶段诱导其更换配偶。通过微卫星DNA分型分析一窝蛋的父系情况。如果留驻雄鸟在第二枚蛋产下之后（第1天）才被移除，它们在这窝蛋中具有完全的父系身份；而如果在第一枚蛋受精前超过1天（小于-2天）被移除，它们则失去所有父系身份。在-2天至1天期间更换雄鸟总是导致一窝蛋出现混合父系情况。在此期间与雌鸟配对仅几天（1 - 3天）的雄鸟平均每次交配日能使雌鸟受精超过一次，在-1天达到峰值。因此，假设观察到的配对关系时间反映了每只雄鸟与雌鸟交配的时间，那么产蛋序列中的第一枚蛋是在受精前不久的交配中受精的，而最后一枚蛋则是在其受精前几天的交配中受精的。我们对交配最重要时期的记录对于理解该物种的性行为具有一些重要意义。
