RPG: Population Dynamics and Life History Evolution in Metapopulations of Social Spiders

植物种群和动物种群被自然地细分。除了偶尔的移民交换或与现有亚单位成员在空出的地点重新定居外，某些物种的种群细分足够强，以至于亚单位在很大程度上彼此独立。这种超种群结构的一个极端例子是群居蜘蛛，这种生物形成的群体既是社会群体，也是相对较小的、自我维持的、很大程度上孤立的群体。使用Anelosimus属的社会性蜘蛛作为模型系统，将遵循这里描述的规划活动的研究将调查如何控制本地种群（在这种情况下，殖民地）的增长参数也会影响整个元种群的结构和稳定性。这项研究将比较那些在繁殖规模上有三倍差异，但在生物学的其他方面相似的物种。这项研究将验证的一个假设是，更大的育雏规模会导致蜂群的规模波动，并经历更频繁的分散和灭绝事件。计算机模拟将通过探索导致局部不稳定动态的生活史参数是否可以在元种群中进化，以及在给定不同程度的局部种群不稳定的情况下，是否可能在元种群水平上保持稳定，来补充这一实证研究。这项计划拨款将使以下工作成为可能：(1)探索将被纳入研究的其他物种和野外地点；(2)测试研究这些社会性蜘蛛种群灭绝和扩散的操作实验的可行性；(3)探索分析野外收集数据类型的其他方法。该项目的实地考察方面包括访问厄瓜多尔的两个热带雨林地区和秘鲁的一个热带雨林地区，以及美国、厄瓜多尔和秘鲁学生的参与。除了解决社会性蜘蛛生物学的有趣方面之外，这项研究将(1)为以下理论提供一个测试：高增长率，结合密度依赖和时间延迟，可能导致不稳定的种群动态或混乱；(2)揭示当地种群灭绝和扩散的原因和后果；(3)揭示群体选择与个体选择在元种群生活史特征进化中的相互作用。这些问题在生态学和进化中具有广泛的意义，并与在破碎景观中保护物种有关。

Aviles 9707474 Plant and animal populations are naturally subdivided. Except for the occasional exchange of migrants or the recolonization of vacated sites with members of existing subunits, population subdivision in some species is strong enough that the subunits are largely independent from one another. An extreme example of such metapopulation structure are the social spiders, organisms that form colonies that are both social groups and relatively small, self-sustaining, and largely isolated populations. Using social spiders in the genus Anelosimus as a model system, the study that will follow the planning activities described here will investigate how parameters that govern the growth of local populations (in this case, colonies) can also affect the structure and stability of the entire metapopulation. The study will compare species that exhibit a three-fold difference in the size of their brood, but are similar in other aspects of their biology. A hypothesis that this study will test is that larger brood sizes lead to colonies that oscillate in size and undergo more frequent dispersal and extinction events. Computer simulations will complement this empirical study by exploring whether life history parameters that lead to local unstable dynamics can evolve in a metapopulation and whether stability at the metapopulation level is possible given different levels of instability of the local populations. This planning grant will make it possible to (1) explore alternative species and field sites to be included in the study, (2) test the feasibility of manipulative experiments to study colony extinction and dispersal in these social spiders, and (3) explore alternative ways of analyzing the type of data to be collected in the field. The field aspects of this project involve visits to two tropical rainforest areas in Ecuador and one in Peru and the participation of American, Ecuadorian, and Peruvian students. In addition to addressing intriguing aspects of the biology o f social spiders, this study will (1) provide a test to the theory that large rates of growth, in combination with density-dependence and time delays, can lead to unstable population dynamics or chaos; (2) shed light on the causes and consequences of local population extinction and dispersal; (3) provide insights into the interplay between group and individual selection in the evolution of life history traits in metapopulations. These are issues of broad significance in ecology and evolution and of relevance to the conservation of species in fragmented landscapes.