Early life and transgenerational stressors impact secondary sexual traits and fitness

Developmental stress from early life challenges impacts adult phenotype across a range of species. However, the potential transgenerational consequences for adult phenotype are largely unknown. Additionally, the possible impacts of natural hatch/birth order and natal brood composition in unmanipulated broods/litters on adult performance has been understudied. This experiment takes a novel approach to studying developmental stress by integrating and assessing multiple potential stressors and multiple secondary sexual traits simultaneously in order to determine how these influence both social and genetic reproductive success. Male zebra finches were colony-reared on high- or low-quality diets; as adults, they reproduced competitively on an intermediate diet. Male visual ornaments (beak color and cheek patch size) were found to be reliable signals of developmental stress, since they showed high sensitivity to multiple early conditions and predicted reproductive success. Contrary to the nut...