Options in a Variable Social System

西方蓝鸟在大多数情况下是一夫一妻制，终身成对，雄性和雌性平均分担哺育后代的责任。然而，一些观察表明，雄性繁殖的机会是有限的。一些雄性不繁殖，而是帮助在父母的巢中喂养雏鸟。另一些则在丧偶雌性的巢中填补空缺，照顾可能是雌性前配偶生育的幼崽；这种明显的利他主义的假定好处是有机会在下一次与雌性交配。再加上雄性繁殖选择的这种差异，繁殖的雄性在使其社会伴侣的卵子受精的程度上存在差异；DNA指纹图谱显示，超过三分之一的巢穴至少有一个后代不是由照顾他们的雄性繁殖的。狄金森博士将使用单基因座指纹技术和田间实验来发现配对外受精的潜在过程，并准确测量育种者、帮助者和领养雄性的健康后果。通过使用微型和微卫星DNA指纹技术对种群进行大规模基因分型，她将确定成功受精的雄性的特征。了解该物种中不寻常的可供选择的生殖行为将为一夫一妻制、双亲照料和合作繁殖的进化提供实质性的见解。迪金森博士将培训三名本科生或刚毕业的生物学专业的野外鸟类学专业的学生。在过去，很高比例的受训人员会继续从事野外生物学的其他工作，或者在大多数情况下，从事动物行为或鸟类学的研究生课程。这些基础研究的结果可能会产生关于鸟类种群和保护生物学的重要信息。

Dickinson, Janis IBN-9507365 Abstract Options in a variable social system Western bluebirds, in most cases, are monogamous, pair for life, and the male and female share equally in feeding offspring. However, several observations suggest that breeding opportunities are limited for males. Some males don't breed, but instead help feed nestlings at their parents' nests. Others fill vacancies at nests of widowed females and care for young that were presumably sired by the female's former mate; the presumed benefit of this apparent altruism is the opportunity to breed with the female the next time around. Superimposed on this variation in the reproductive options of males, breeding males vary in the extent to which they fertilize eggs of their social mates; DNA fingerprinting has revealed that over one-third of nests have at least one offspring that is not sired by the caregiving male. Dr. Dickinson will use single-locus fingerprinting techniques and field experiments to discover the processes underlying extrapair fertilization and to measure accurately the fitness consequences for breeders, helpers, and adoptive males. Through large-scale genotyping of the population using mini- and micro-satellite DNA fingerprinting techniques, she will characterize males successful in fertilization. Understanding the unusual array of alternative reproductive behaviors in this species will provide substantial insights into the evolution of monogamy, biparental care, and cooperative breeding. Dr. Dickinson will train three undergraduate or recently graduated biology majors in field ornithology. In the past, a high proportion of trainees have gone on to other jobs in field biology or, in most cases, graduate programs in animal behavior or ornithology. The results of these basic studies are likely to yield significant information concerning the population and conservation biology of avian species.