Sheppard Jennifer L, Clark Robert G, Devries James H, Brasher Michael G
Department of Biology, 112 Science Place, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada.
Behav Processes. 2013 Nov;100:82-90. doi: 10.1016/j.beproc.2013.07.024. Epub 2013 Aug 22.
In accordance with the differential allocation hypothesis, females are expected to increase their reproductive investment when mated to high-quality males. In waterfowl, reproductive, investment increased when captive female mallards (Anas platyrhynchos) were mated to more attractive males, but information for wild ducks is lacking. Studies of waterfowl mating systems have focused primarily on the importance of plumage coloration of males and female mate choice, whereas investigations of reproductive ecology examine female attributes and virtually ignore the role of males in investment decisions. Here, we used unique data for 253 pairs of wild mallards to test whether females mated to high-quality males would increase reproductive effort and reproduce more successfully. We derived measurements of female and male body size and condition, and indices of male plumage quality, and related these traits to patterns of reproductive effort and performance of females. Consistent with predictions, yearling females nested earlier and had higher nest survival when mated to males with better plumage scores. Furthermore, when paired with larger bodied males, yearling females renested more often, and nest and brood survival increased among older females. Although the strength of male effects varied with breeding stage and female age or experience, this is one of a few studies to demonstrate an additive effect of male quality on investment and success of females, in free-ranging birds.
根据差异分配假说，当与高质量雄性交配时，雌性有望增加其繁殖投入。在水禽中，当圈养的雌性绿头鸭（Anas platyrhynchos）与更具吸引力的雄性交配时，繁殖投入会增加，但野生鸭类的相关信息却很缺乏。水禽交配系统的研究主要集中在雄性羽毛颜色的重要性和雌性的配偶选择上，而繁殖生态学的研究则关注雌性特征，几乎忽略了雄性在投资决策中的作用。在这里，我们利用253对野生绿头鸭的独特数据，来测试与高质量雄性交配的雌性是否会增加繁殖努力并更成功地繁殖。我们得出了雌性和雄性的体型及身体状况测量值，以及雄性羽毛质量指数，并将这些特征与雌性的繁殖努力模式和繁殖表现联系起来。与预测一致，一岁龄雌性在与羽毛得分更高的雄性交配时，筑巢更早，巢的存活率更高。此外，当与体型较大的雄性配对时，一岁龄雌性更频繁地重新筑巢，而在年龄较大的雌性中巢和雏鸟的存活率增加。尽管雄性效应的强度随繁殖阶段以及雌性年龄或经验而变化，但这是少数几项证明雄性质量对自由放养鸟类中雌性的投资和繁殖成功具有累加效应的研究之一。
