Meeting Abstract

30.7  Sunday, Jan. 5 11:30  From environmental endocrinology to hormone evolution: adaptations to a changing environment HAU, M; Max Planck Institute for Ornithology, Seewiesen and University of Konstanz mhau@orn.mpg.de

Seminal empirical and conceptual work by John Wingfield, Marilyn Ramenofsky and collaborators helped establish the field of environmental endocrinology by providing a wealth of knowledge on how environmental and social conditions influence hormonal responses of individuals, populations and species. One of John Wingfield’s stimulating approaches included studying species that diverge in their life style from that of most well-studied temperate zone birds. For example, in my own work with John we could elucidate some ways in which the hormonal organization of a tropical bird diverges from that of many temperate zone species. This work and subsequent comparative studies spurred my interest in unraveling the evolutionary patterns that shape hormonal organization. Focusing on our current model system, the great tit (Parus major), I will review recent findings on the fitness relevance of and the selection pressures on hormonal phenotypes. Specifically, I will present data from a multi-year study in which we determined baseline and stress-induced corticosterone concentrations in free-living great tits at different times of year and relate it to measures of fitness – reproductive success and survival. I will discuss our findings on selection pressures, direction of selection, and seasonal variation in light of concepts on the evolution of hormonally regulated traits. Furthermore, I will put our data into context with findings on the repeatability and heritability of hormonal traits and highlight possible ways to improve our understanding of the speed at which hormonally regulated traits evolve. As pointed out by John Wingfield, such knowledge may become crucial in helping us to evaluate the threat that changing environments pose to wild populations.