Table 1.
Means (and s.e.) and t-test results for barbule morphological variables of matte and glossy black feathers. Significant (p < 0.05) results are bolded.
| variable | glossy | matte | t (d.f. = 14) | p |
|---|---|---|---|---|
| barbule width (µm) | 12.92 (1.47) | 14.01 (1.16) | 0.39 | 0.69 |
| barbule thickness (µm) | 3.05 (0.19) | 3.26 (0.19) | 0.55 | 0.59 |
| barbule aspect ratio | 4.41 (0.51) | 4.36 (0.35) | 0.95 | 0.36 |
| keratin cortex thickness (nm)a | 162.56 (10.82) | 330.65 (48.22) | 3.25 | 0.005 |
| keratin cortex CV (%) | 23.91 (2.45) | 44.02 (5.66) | 2.24 | 0.04 |
| melanin layer thickness (nm) | 471.15 (42.02) | 426.04 (23.37) | −0.64 | 0.53 |
| melanin layer discontinuity (%) | 16.44 (1.49) | 32.92 (2.27) | 4.16 | <0.001 |
| number of gaps in the melanin layer | 8.36 (0.54) | 12.73 (0.83) | 3.04 | 0.008 |
| proportion of melanin (%) | 51.68 (2.35) | 45.11 (2.75) | −1.25 | 0.23 |
aLog-transformed for statistical analyses.