This action funds an NSF Postdoctoral Research Fellowship for FY 2010. The fellowship supports a research and training plan entitled "Understanding Cooperation on Dynamic Social Networks through Actor-Driven Models of Network Evolution" for Andrew J. Edelman. The host institution for this research is the University of Wyoming, and the sponsoring scientist is David McDonald.
Cooperation is a common feature of biological systems, occurring at many levels of organization (e.g., genes, cells, individuals, and groups) and a wide variety of species. In particular, humans and many animal species exhibit complex cooperation among unrelated individuals. Understanding the evolutionary processes that favor complex cooperation is a fundamental challenge of modern biology and crucial to promoting peaceful societies. Recent theoretical models have been successful in explaining some forms of cooperation through indirect reciprocity, which is based on the principle "I scratch your back and someone else will scratch mine." Indirect reciprocity occurs when individuals that act altruistically are more likely to receive altruistic acts in the future. This research tests whether indirect reciprocity explains the dynamics of social networks in male long-tailed manakins (Chiroxiphia linearis). Males of this species perform cooperative displays that attract females to lek sites for mating, but only the top-ranked alpha male mates. Participation in displays appears to determine male social status and rise to alpha rank. The research employs graph theory, network analysis, and statistical modeling to test indirect reciprocity models on a long-term dataset of manakin social dynamics. Specifically, actor-driven network models developed by sociologists are being implemented to determine whether indirect reciprocity explains cooperation among male manakins.
Training will include: 1) social network analysis, 2) statistical modeling of dynamic networks, 3) long-term data analysis, and 4) student mentoring. Broader impacts of this research will include: 1) mentoring students, including those from underrepresented groups, in bioinformatics skills, 2) disseminating research to a broad audience through public-outreach publications and presentations, 3) providing empirical-based feedback regarding the applicability of leading-edge theory to natural systems, 4) novel applications of bioinformatics to animal social networks, and 5) understanding the conditions that can foster cooperation and discourage aggression.
This project supported Dr. Edelman’s postdoctoral training and research in biological informatics. During the two-year project, Dr. Edelman engaged in a variety of research, teaching, and outreach activities. His research focused on implementing statistical techniques developed for studying human societies to examine what processes are important to forming the network of social interactions in animal societies. Social network analysis provides a powerful framework for linking individual relationships to the larger social structure in complex animal societies. Networks model social relationships by depicting individuals as nodes connected by social ties called links or edges. Through statistical modeling of links between individuals, social networks can be used to tease apart the various factors that influence social structure. Dr. Edelman collaborated with his mentor, Dr. McDonald, to use these advanced network techniques to understand the development of cooperative behavior among males in the tropical bird, the long-tailed manakin. Long-tailed manakins have an unusual mating system in which pairs of unrelated males, at the top of overlapping teams of as many as 15 males, cooperate to perform dual-male song and dance courtship displays. Dr. McDonald has collected a 16-year dataset recording the cooperative displays of males at a study site in Costa Rica. These long-term behavioral data were used to construct social networks of the cooperative interactions among males over several time periods. By using advanced network modeling techniques, Dr. Edelman discovered a combination of three factors drove the overall social structure of male manakin: close spatial proximity between birds, maintenance of long-term partnerships, and formation of relationships with "friends of a friend". These three effects, in concert, explained the social network properties during all 16 years of observations, the approximate lifespan of these manakins. The importance of these processes to shaping manakin social network structure can be attributed to the unique mating system that requires males to queue and cooperatively display at together over long time periods. Dr. Edelman has written a manuscript (currently in review) detailing the results of this study. Dr. Edelman has also coauthored a paper (currently in review) highlighting the challenges and future directions for animal social network research. Dr. Edelman has also participated in teaching and outreach activities. During his fellowship, he attended several workshops on developing effective teaching techniques for undergraduate courses. He used this training to serve as a guest lecturer and co-instructor at the University of Wyoming for courses in general biology, mammalogy, and fish/wildlife management. During his postdoctoral fellowship, Dr. Edelman has given numerous presentations at scientific meetings, university seminars, and public meetings. He has also participated in several programs through scientific professional organizations to promote student participation in the biological sciences. In addition, Dr. Edelman assisted in organizing a regional symposium on network science in biological, social, and geographic systems during 2012. The goals of this symposium were to highlight research, foster interdisciplinary cooperation, and promote student involvement in network sciences. Over 30 individuals attended the meeting including many students. Overall, Dr. Edelman’s postdoctoral research has contributed to the understanding of animal behavior and the techniques used to study this topic. The use of social networks in understanding the relationships among individuals in animal societies is still relatively new and unrefined. Dr. Edelman has implemented several novel approaches to expand the scope of social network techniques. Most research on animal social networks has been descriptive and exploratory in nature. Dr. Edelman’s research has pioneered a more rigorous approach, which uses statistical modeling to explore how different factors in concert affect formation of animal social networks.
