Table 5. Relatedness and sibship inferred by COLONY.
| Population | Number of dyads | Average relatedness | Average frequency of sibship | |
|---|---|---|---|---|
| Paria (low predation) | Within shoals | 300 | 0.0346 | 0.131 |
| Between shoals | 2550 | 0.0259 | 0.1004 | |
| Difference (95% CI under H0) | NS | 0.0086 (−0.0083, 0.0099) | 0.0306 (−0.0316, 0.0371) | |
| Upper Aripo (low predation) | Within shoals | 320 | 0.0086 | 0.0344 |
| Between shoals | 6235 | 0.0163 | 0.063 | |
| Difference (95% CI under H0) | NS | −0.0077 (−0.0065, 0.0078) | −0.0285 (−0.025, 0.0293) | |
| Lower Aripo (high predation) | Within shoals | 384 | 0.0216 | 0.0811 |
| Between shoals | 4467 | 0.0123 | 0.0485 | |
| Difference (95% CI under H0) | * | 0.0093 (−0.0055, 0.0062) | 0.0327 (−0.0212, 0.024) | |
| Arouca (high predation) | Within shoals | 384 | 0.0203 | 0.0734 |
| Between shoals | 4467 | 0.0104 | 0.0411 | |
| Difference (95% CI under H0) | * | 0.0099 (−0.005, 0.0058) | 0.0324 (−0.0191, 0.0229) |
Average relatedness and average frequency of sib dyads within and between shoals for each population were calculated from sibship assignments, and the differences within and between shoals were tested by bootstrapping (significance level: *P<0.05 and NS non-significant).