Double M, Cockburn A
Evolutionary Ecology Group, Division of Botany and Zoology, Australian National University, Canberra ACT.
Proc Biol Sci. 2000 Mar 7;267(1442):465-70. doi: 10.1098/rspb.2000.1023.
Despite great interest in the use of extra-pair mating as a tool for examining female choice and intersexual selection, the underlying assumption of female control has proved difficult to verify empirically. We combined microsatellite genotyping and radiotelemetry of fertile females in order to investigate mate choice in superb fairy-wrens Malurus cyaneus, the bird with the highest known rate of extra-pair fertilization. All five females radio tracked during the peak of fertility, two to four days before the first egg is laid, undertook pre-dawn forays. All extra-pair young produced by the female were sired by a male visited during their forays, indicating that females control extra-pair fertilizations. In a larger sample of paternity data, some broods were sired by two extra-group males. In virtually all the cases the territory of the two sires were on an identical linear trajectory from the female's territory. This again suggests that extra-group paternity in superb fairy-wrens is directly linked to female extra-territorial forays. In other species mixed paternity has been taken to indicate that females attempt to insure against infertile pairings or try to maximize the genetic diversity of their brood. However, in fairy-wrens the likelihood of multiple extra-group paternity increased greatly as females traversed more territories in order to mate, perhaps suggesting that females which foray further are more likely to have difficulties locating the preferred male.
尽管人们对将配偶外交配作为研究雌性选择和两性间选择的工具兴趣浓厚，但雌性控制这一潜在假设在实证研究中却难以得到验证。我们结合了微卫星基因分型和对可育雌性的无线电遥测技术，以研究华丽细尾鹩莺（Malurus cyaneus）的配偶选择，这种鸟有着已知最高的配偶外交配率。在生育高峰期，即产卵前两到四天，对五只接受无线电追踪的雌性进行观察，发现它们都会在黎明前外出。雌性所产的所有配偶外交配后代均由其外出期间拜访的雄性所生，这表明雌性控制着配偶外交配。在更大的亲子关系数据样本中，一些窝雏由两只来自其他群体的雄性所生。在几乎所有情况下，这两只雄性的领地都位于从雌性领地出发的同一条直线轨迹上。这再次表明，华丽细尾鹩莺的群体外亲子关系与雌性的领地外外出直接相关。在其他物种中，混合亲子关系被认为表明雌性试图确保避免不育配对，或试图使窝雏的遗传多样性最大化。然而，在细尾鹩莺中，随着雌性为了交配穿越更多领地，群体外多个雄性参与亲子关系的可能性大幅增加，这可能表明外出更远的雌性更有可能在寻找首选雄性时遇到困难。
