Meeting Abstract

P2.205  Saturday, Jan. 5  Geographic variation in morphology of dark-eyed juncos and implications for population divergence FERREE, E.D.; Claremont Colleges, CA eferree@kecksci.claremont.edu

When geographic variation in morphology develops among closely related populations, it can help drive genetic divergence, and eventually speciation, when those morphological traits are the basis for social interactions that influence reproduction. The North American dark-eyed junco is an interesting case in speciation, because even though there are numerous subspecies with distinct breeding ranges and plumage coloration, based on genetic data and the presence of hybrid populations they are considered to belong to one species. Research within several junco populations has shown first, that wing length and the proportion of the tail feathers that are white (“tail white”) influence an individual’s dominance status and mating success, and second, that these traits can undergo rapid evolution when social and environmental conditions change. Using measurements taken from museum specimens, I determined how the magnitude, correlation between and sexual dimorphism of wing length and tail white varied geographically across 13 dark-eyed junco subspecies. I found significant variation in both traits, as well as in how they co-varied and the degree of sexual dimorphism. I discuss the results in relation to what they may indicate about the maintenance or further divergence of the junco subspecies.