Social environment effects on hormones and the integrated phenotype

The strategies and the signals that individuals use to attract mates and breed often depend on an individual's social status relative to others in the population. That status can fluctuate as group composition changes and/or other individuals change in rank. Accordingly, the hormonal and genetic mechanisms that underlie such behavior and signals are likely to be sensitive to social conditions. The project examines the mechanisms that allow for behavioral flexibility, and the ways that those mechanisms evolve, using Australian fairy-wrens (genus Malurus) as a model system. These species are uniquely suited to this research because they show pronounced variation, across both individuals and populations, in the visual signals that individuals use to attract mates. Hormones (particularly androgens like testosterone) are known to regulate the development of these signals. The project examines the effects of social interactions on hormones and gene expression in brain and other tissues and uses experimental manipulation in the field to demonstrate the underlying causes. A combination of observational, genomic and hormone manipulation approaches are used to examine the extent to which androgens affect whole suites of characters to produce an integrated reproductive phenotype. Overall, this research will contribute to a better understanding of the hormonal and genomic mechanisms that allow individuals to adjust to a constantly changing social environment.