Table 1.
Inbreeding depression (δ) in body size, ejaculate traits and condition (capture time). Traits that showed significant inbreeding depression are in bold. Means ± SE (n) are given. Differences between means were tested using a LMM in which female identity was entered as random factor, and inbred/outbred as fixed factor (significant differences in bold), with the exception of capture test, for which one randomly selected male per family was used.
| Trait | Inbred | Outbred | Statistic | D df | P | δ (%) |
|---|---|---|---|---|---|---|
| Body size (SL, mm) | 15.88 ± 0.19 (30) | 16.05 ± 0.20 (29) | F = 0.15 | 30.8 | 0.70 | 1.1 |
| Sperm number (×106) | 4.24 ± 0.63 (30) | 6.59 ± 0.73 (29) | F = 5.311 | 23.6 | 0.03 | 35.7 |
| Sperm velocity (VAP, μm/s) | 103.63 ± 2.53 (25) | 102.13 ± 1.90 (28) | F = 0.24 | 19.8 | 0.63 | −1.5 |
| Sperm velocity (VCL, μm/s) | 128.25 ± 1.96 (25) | 128.29 ± 1.48 (28) | F = 0.01 | 23.7 | 0.93 | 0.0 |
| Sperm head length (μm) | 4.16 ± 0.03 (25) | 4.21 ± 0.02 (28) | F = 2.06 | 25.3 | 0.16 | 1.2 |
| Sperm midpiece length (μm) | 4.64 ± 0.07 (25) | 4.58 ± 0.08 (28) | F = 0.14 | 27.8 | 0.71 | −1.3 |
| Total sperm length (μm) | 55.24 ± 0.23 (25) | 54.65 ± 0.28 (28) | F = 1.83 | 28.2 | 0.19 | −1.1 |
| Capture time (s) | 6.92 ± 1.92 (17) | 14.4 ± 3.18 (16) | t = 2.472 | 31 | 0.02 | 51.9 |
1
Male body size (SL) entered as covariate.
2
Log-transformed before analysis; one male per family was used (outbred, n = 17; inbred, n = 16).