Testing the Relative Importance of Habitat Saturation and Benefis of Philopatry on Delayed Dispersal

合作繁殖，即多个成年人共享一个巢，并照顾在该巢出生的年轻人，在脊椎动物中是不寻常的。 延迟扩散是合作繁殖的一个标志，可能是由于缺乏空闲的领土或对留在出生地的后代没有好处。 研究人员建议在一种合作繁殖的哺乳动物草原田鼠身上测试这些替代品。 他们将在野外围栏中建立高密度和低密度的草原田鼠种群。 据预测，在高密度地区，留在家中的青少年比例和大家庭群体的规模将更大。 在这些相同的人群中，研究人员还将测试关于留在家中的后代的潜在益处的预测。 在整个野外实验中，他们将使用遗传技术来确定群体成员的亲属关系。 这项研究将是第一个联合收割机的现场实验操纵人口密度与遗传数据的亲属关系，并应允许调查人员检查先前提到的想法延迟扩散。 这项研究的结果将有助于我们理解人口统计学和社会因素塑造哺乳动物行为的方式。 这项研究将提供机会，让学生获得第一手经验的应用科学方法。 研究人员还计划将小学和高中教师介绍给这项研究，作为夏季研讨会的一部分。

Cooperative breeding, in which multiple adults share a nest and care for young born at that nest, is unusual among vertebrates. Delayed dispersal, a hallmark of cooperative breeding, can result from lack of vacant territories or benefits to offspring that remain at the nest where they were born. The investigators propose to test these alternatives in a cooperatively breeding mammal, the prairie vole. They will establish prairie vole populations at high and low densities in field enclosures. The prediction is that the proportion of juveniles that remain at home and the size of extended family groups will be greater at high density. In these same populations the investigators also will test predictions regarding potential benefits to offspring that remain at home. Throughout the field experiment, they will use genetic techniques to determine kinship of group members. This study will be the first to combine a field experiment manipulating population density with genetic data on kinship and should allow the investigators to examine previously mentioned ideas about delayed dispersal. The results of this study will contribute to our understanding of the ways in which demographic and social factors shape mammalian behavior. This study will provide opportunities for students to gain first-hand experience in the application of the scientific method. The investigators also plan to introduce grade school and high school teachers to this research as part of a summer workshop.