Dominance survival and enzyme polymorphism in dark eyed juncos junco hyemalis
Baker, M.C.; Fox, S.F.
Evolution 32(4): 697-711
ISSN/ISBN: 0014-3820 DOI: 10.2307/2407486
The genetic structure of wintering populations of dark-eyed juncos was examined by starch gel electrophoresis. Among different flocks and different years, only mild heterogeneity was found. These populations were polymorphic at 16.6% of 18 loci examined. The average number of variants/polymorphic locus is 3.33, and the average proportion of loci heterozygous for an individual is 0.053. Using color marked birds, it was established that in the dominance hierarchy of a flock, high ranking birds were usually heterozygous for the enzyme L-leucylglyclglycine peptidase. Employing 4 experimental flocks captive in aviaries, under conditions of food restriction dominant birds were likely to show higher survival than low ranking birds. In order of decreasing importance, survival in the aviaries (defined as the maintenance of body weight above a criterion threshold) could be predicted from dominance rank, genotype, body weight, sex, bill width, bill length, hood coloration and tarsal length. The single best predictor of high dominance rank was long wing length.