SG/LTREB Renewal: Spatiotemporal Fitness Variation and Avian Group Size

许多群居动物生活在大小不一的群体中。在特定的年份里，个体在特定规模的群体中似乎往往存活或繁殖得更好，因此生态学家一直困惑于为什么规模不太成功的群体继续存在。一种可能性是，生态条件的变化，如食物供应或寄生虫的存在，和/或气候条件的变化，如一年有多湿，导致某些群体规模在某些年份或某些地区最成功，但在其他情况下，不同的群体规模最成功。然而，在长期和广泛的地理区域内，不同规模的群体的优势是否以这种方式波动是未知的。这只能通过长期的研究来解决，这些研究测量了不同年份和地理区域的不同群体的动物的成功。这项研究将通过测量一种群居鸟类悬崖燕的个体繁殖成功率来解决这个问题，悬崖燕在1到6000个鸟巢的群体中繁殖。崖燕遍布北美西部的大部分地区，是世界上最具社会性的陆地鸟类之一。这项工作正在调查特定群体规模的成本和收益是否会在数年内有规律地变化，以解释群体规模的长期持续变化。这项研究涉及本科生，并为他们提供野外生态学的密集研究经验和训练。通过在加利福尼亚州圣胡安卡皮斯特拉诺教会举办的燕子日节上发表年度演讲，在与该活动相关的国家媒体上露面，以及维护一个关于研究和崖燕的网站，来进行公众宣传。这一建议建立在对群居鸟类悬崖燕的长期研究基础上，悬崖燕生活在大小差异很大的群体中，并正在调查繁殖成功的波动选择是否可以解释群体规模的变化。收集到的数据将用于研究不同大小的蜂群每年的繁殖成功率。这是通过系统地收集每年多达40个崖燕种群羽化成功的数据来完成的。这项工作还通过检查体外寄生的程度、繁殖物候和其他以巢和群体为基础的变量，关注繁殖成功变化的近因生态驱动因素，从而确定导致不同群体繁殖成功年度变化的气候和其他因素。在这个项目中收集的信息，以及现有的成年和一岁鸟的年存活率数据，将使人们能够估计占据不同大小群体的鸟类的相对终生繁殖成功率。这项研究将有助于更好地理解群体规模如何长期影响适应性，有助于解释群体规模的广泛变化，这是大多数群居动物的特征，揭示气候变化对动物社会行为的潜在影响，并提供波动选择在产生和维持行为变化中的重要性的测试。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Many social animals live in groups of different sizes. Individuals often seem to survive or reproduce better in groups of particular sizes in a given year, and ecologists have thus been puzzled as to why groups with less successful sizes continue to exist. One possibility is that changes in ecological conditions such as food availability or the presence of parasites, and/or climatic conditions such as how wet a year is, lead to certain group sizes being most successful in some years or in some areas, but different ones being most successful in other circumstances. However, whether or not the advantages of different sized groups fluctuate in this way over the long term and across broad geographic areas is unknown. This can only be addressed with long-term research that measures the success of animals in different groups in different years and geographic regions. This research will address this by measuring the reproductive success of individuals of a social bird, the cliff swallow, which breeds in colonies ranging from 1 to 6000 nests. Cliff swallows are found throughout much of western North America and are one of the most highly social land birds in the world. The work is investigating whether the costs and benefits of particular colony sizes change regularly enough among years to explain the long-term persistence of variation in group size. This research involves undergraduate students and offers them intensive research experience and training in field ecology. Public outreach is conducted by giving annual lectures at the Swallows Day festival at Mission San Juan Capistrano in California, appearance on national media associated with that event, and maintenance of a web site about the research and cliff swallows generally. This proposal builds on a long-term study of a social bird, the cliff swallow, that lives in colonies of widely different sizes, and is investigating whether fluctuating selection on reproductive success can explain variation in group size. The data gathered will be applied to study annual reproductive success in colonies of different sizes from year to year. This is done by systematically collecting data on fledging success at up to 40 cliff swallow colonies each year. The work also focuses on the proximate ecological drivers of variation in reproductive success by examining the extent of ectoparasitism, breeding phenology, and other nest- and colony-based variables, allowing identification of climatic and other factors that lead to annual variation in reproductive success in different groups. The information gathered in this project, along with existing data on annual survival of breeding adults and first-year birds, will enable estimation of relative lifetime reproductive success of birds occupying different sized colonies. This study will allow better understanding of how group size affects fitness over the long term, assist in interpreting the extensive variation in group size that is characteristic of most social animals, reveal the potential influence of climatic variability on animal social behavior, and provide a test of the importance of fluctuating selection in generating and maintaining behavioral variation.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.