International Research Fellowship Program: Evolution of Aggression as a Key to the Range Expansion of a Passerine Bird

Duckworth Renee A, Durham NC

Investigators

Abstract

0601751 Duckworth The International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad. This award will support a twenty-four-month research fellowship by Dr. Renee A. Duckworth to work with Dr. Loeske Kruuk at the University of Edinburgh in the UK for twelve months, and with Dr. Jonathan Losos at Harvard in the U.S. for twelve months. Interspecific competition is an important evolutionary force that shapes the phenotypes and influences the geographic ranges of species. Yet, we know very little about the evolutionary dynamics of traits involved in competitive interactions, particularly at species' borders. This is because we must often rely on indirect evidence of competition and this makes it difficult to identify both, the major resource that is the focus of competition between two species, as well as the specific trait or traits that account for differences in competitive ability. Here, I capitalize on a unique 'natural experiment' in which western bluebirds (Sialia mexicana) are displacing mountain bluebirds (S. currucoides), a closely related congener, and are rapidly re-colonizing their historical range. In this system, male aggression determines the outcome of competition over nest cavities - a limited resource that is critical to the survival of both species. The central goal of the proposed research is to integrate quantitative genetic approaches with large scale field experiments on community formation to understand the evolutionary causes of variation in aggression across the contact zone of the two species. This project will provide new insights into the evolution of a complex behavioral trait and will also shed light on the role of behavioral and ecological interactions in the conservation of cavity nesting species. Dr. Kruuk has pioneered new techniques in quantitative genetics to test hypotheses on the evolutionary significance of variation in complex traits in wild populations. Dr. Losos' integrative research program combines large scale field experiments, studies of functional morphology, and phylogenetic approaches to understand evolutionary and ecological interactions among species.