a | Uropygial gland volume | Â | Â | Â | Â | Â | |
 | Females |  |  | Estimate ± SE | df | F | P |
 |  | Date |  | 0.01 ± 0.01 | 1,50 | 4.25 | 0.04 |
 |  | Year |  | 0.15 ± 0.04 | 1,50 | 13.89 | <0.001 |
 |  | Wing length |  | 0.41 ± 0.13 | 1,50 | 10.6 | 0.002 |
 | Males |  | Estimate ± SE | df | F | P | |
 |  | Date |  | −0.01 ± 0.004 | 1,36 | 7,0 | 0.01 |
 |  | Year |  | 0.21 ± 0.06 | 1,36 | 13,0 | 0.001 |
 |  | Body condition |  | 0.16 ± 0.04 | 1,36 | 12.5 | 0.001 |
 |  | Treatment | Nisin | 0.16 ± 0.07 | 2,36 | 4.3 | 0.02 |
 |  |  | TSB | 0.16 ± 0.06 |  |  |  |
b | Uropygial gland composition - PC2 | Â | Â | Â | Â | Â | |
 | Females |  |  | Estimate ± SE | df | F | P |
 |  | Date |  | 0.07 ± 0.03 | 1,27 | 5.5 | 0.03 |
 |  | Treatment | Nisin | 2.38 ± 0.69 | 2,27 | 6.5 | 0.005 |
 |  |  | TSB | 1.95 ± 0.71 |  |  |  |
 | Males |  | Estimate ± SE | df | F | P | |
 |  | Body condition |  | −0.51 ± 0.22 | 1,21 | 5.4 | 0.03 |