Fig. 5

Statistically significant partial associations between scores from Principal Component (PC) axes summarizing relative abundance of detected volatiles (dependent variables) and bacterial (i.e., bacterial genera) (independent factors) of the uropygial secretion of female (green dots: a, b and c) and nestling (blue dots, d and e) hoopoes, and of their nest materials (bacterial communities) and nest-boxes (volatiles profiles) collected at the beginning (grey dots, f) and at the end (brown dots, g, h and i) of the nestling period. Each PC-axis was named by a composition of letters that indicate the type of samples. The first letter indicates whether the sample corresponds to bacteria (B) or volatiles (V), the second letter indicates whether the sample is from secretions of females (SF), secretion of nestlings (SN) or nest material (M). Finally, for distinguishing between types of samples that were collected at the beginning (1) and at the end (2) of the nestling period, the name finished with a number. Lines are regression lines