Figure 2: Nature Communications

Fig. 2

From: Carotenoid metabolism strengthens the link between feather coloration and individual quality

Fig. 2

Results of the multilevel phylogenetic meta-analyses. The weighted mean correlation (Zr) betwen feather color richness and measures of individual quality. a The strength of the association was calculated for all published studies without consideration of the carotenoid type in the feathers of the study bird (Combined, gray circles, number of effect sizes (n) = 191), for only studies of bird species with plumage coloration derived from converted carotenoids (red circles, n = 92), and for only studies of bird species with plumage coloration derived from dietary carotenoids (yellow circles, n = 99). Proxies of quality were divided into (b), body condition (overall: n = 35, converted: n = 18, dietary: n = 17), (c) immune and oxidative physiology (overall: n = 42, converted: n = 21, dietary: n = 21), (d) parasite resistance (overall: n = 49, converted: n = 30, dietary: n = 19), and (e) aspects of parental and reproductive quality (overall: n = 65, converted: n = 23, dietary: n = 42). Circle size is inversely proportional to the variance of the mean effect size. Horizontal lines are error bars that represent 95% credible intervals. Effect size estimates with credible intervals that do not include zero are statistically significant effects (α = 0.05)