Fig. 2
From: Natural variation in yolk fatty acids, but not androgens, predicts offspring fitness in a wild bird
Relationships between egg yolk components and physiological traits in great tit nestlings on days (a) 6 and (b) 12. Yolk components are grouped based on a principal component analysis. PC1 was mainly represented by high concentrations of vitamin E (α-tocopherol) and ω-6 polyunsaturated fatty acids (PUFAs), PC2 by high concentrations of saturated fatty acids (SFAs), mono-unsaturated fatty acids (MUFAs) and ω-3 PUFAs, and PC3 by high concentrations of androgens (androstenedione, 5α-dihydrotestosterone and testosterone) and carotenoids (lutein and zeaxanthin; Additional file 1). Nestling oxidative status and body condition are indicated with yellow and green shading, respectively. Shown are the standardized effect sizes with their corresponding 95% credible intervals (CrIs). Filled circles indicate statistically meaningful support (i.e., if the mean difference between compared estimates is higher than 0.95) for the effect of a set of yolk components on physiological traits. Oxidative status parameters: OXY, non-enzymatic antioxidants present in plasma; GPX, enzymatic antioxidant present in red blood cells; ROMs, reactive oxygen metabolites present in plasma