LTREB/SG: Spatiotemporal fitness variation and avian group size

University Of Tulsa, Tulsa OK

Investigators

Abstract

Many social organisms live in groups of variable size. Group size has many important consequences, such as affecting the spread and transmission of infectious diseases both within the group and to members of other groups. This project seeks to understand why groups of variable size persist over long-term time scales. As we better understand what promotes variability in group size, we can better predict the extent to which the costs or benefits of group living will change over time. One popular but untested hypothesis is that climatic differences between years cause variation in food supply or in populations of parasites and pathogens, and this in turn causes the payoffs of different group sizes to vary annually. This project builds on a long-term study of a social bird, the cliff swallow, which lives in colonies of widely different sizes, and seeks to investigate whether changing selection on the animals' survival and reproductive success can explain annual variation in group size. The research addresses one of the most fundamental questions in evolutionary ecology. This project will test the prediction that success of individuals will increase with group size in some years, decrease with group size in others, and remain unchanged in yet other years. It will be determined to what degree the birds' annual nesting success varies from year to year in colonies of different sizes. This will be investigated by systematically collecting data at 20-25 colonies each year. The work will determine the causes of variation in reproductive success by measuring the extent of parasite infestation, time of breeding, bird condition, and other factors. This study will promote better understanding of how group size affects individuals' lifetime reproductive success across long-term time scales, assist in interpreting the extensive variation in group size that is characteristic of many organisms, and reveal the potential influence of recent climatic changes on social behavior. The research will involve women, Native Americans, and students from the Great Plains, promoting STEM training of underrepresented groups with respect to gender, ethnicity, and geographic region.