Table 2.
The effects of brood size manipulation on T-cell-mediated immune response, body size and tarsus length in blue tit nestlings, analysed with mixed model nested ANOVA (Proc Mixed in SAS) with brood size manipulation (control versus enlarged broods), offspring sex and their interaction as fixed factors, and pair of matched nests and nest ID (nested in brood size manipulation and pair) as random factors. (Estimate (±s.e.) denotes variance components.)
| source | estimate | s.e. | d.f. | F | p |
|---|---|---|---|---|---|
| immune response | |||||
| brood size manipulation | 1, 42 | 4.68 | 0.036 | ||
| sex | 1, 21 | 5.86 | 0.025 | ||
| brood size manipulation×sex | 1, 443 | 4.06 | 0.045 | ||
| nest ID (brood size manipulation, pair) | 0.008 | 0.004 | |||
| pair | 0.001 | 0.003 | |||
| pair×sex | 0.002 | 0.002 | |||
| body mass | |||||
| brood size manipulation | 1, 42 | 4.22 | 0.046 | ||
| sex | 1, 21 | 106.73 | <0.0001 | ||
| brood size manipulation×sex | 1, 454 | 0.38 | 0.540 | ||
| nest ID (brood size manipulation, pair) | 0.353 | 0.084 | |||
| pair | 0 | ||||
| pair×sex | 0.002 | 0.009 | |||
| tarsus length | |||||
| brood size manipulation | 1, 42 | 1.77 | 0.191 | ||
| sex | 1, 21 | 194.42 | <0.0001 | ||
| brood size manipulation×sex | 1, 453 | 4.91 | 0.027 | ||
| nest ID (brood size manipulation, pair) | 0.085 | 0.031 | |||
| pair | 0.043 | 0.033 | |||
| pair×sex | 0.0002 | 0.005 |