Table 2.
Linear Mixed Model results for examining relationships between RI values and predictors across species pairs, for each barrier.
| Pollen-Pistil RI (n=65; 42) | Fruit Set RI (n=74; 44) | Fruit Size RI (n=44; 33) | Seed Set RI (n=44; 33) | Seed Viability RI (n=44; 33) | F1 Pollen Viability RI (n=13; 9) | F1 Fruit Set RI (n=13; 9) | F1 Fruit Size RI (n=9; 6) | F1 Seed Set RI (n=9; 6) | Total Postzygotic RI (n=74; 44) | Total RI (n=74; 44) | |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Separate Reciprocal Data | |||||||||||
| Fixed Effects | |||||||||||
| Intercept | 0.059 (0.038) | 0.475 (0.118) | 0.090 (0.132) | 0.120 (0.134) | 0.895 (0.066) | −0.047 (0.137) | −0.372 (0.118) | −0.347 (0.196) | 0.365 (0.162) | 0.664 (0.127) | 0.664 (0.127) |
| Genetic Distance | 7.445 (4.676) | 13.905** (3.828) | 11.928* (4.824) | 37.580* (6.240) | 54.432*** (6.204) | 57.790 (24.785) | 12.868* (5.214) | 12.868* (5.214) | |||
| Geograph. Distance | −0.213* (0.047) | −0.246* (0.072) | −0.267 (0.175) | ||||||||
| Eco. Distance | |||||||||||
| Morph. Distance | |||||||||||
| Style Distance | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | |
| Random Effects | |||||||||||
| Phylogenetic Structure | 0.000 (0.000) | 0.003 (0.057) | 0.000 (0.000) | 0.000 (0.000) | 0.000 (0.019) | 0.000 (0.000) | 0.000 (0.000) | 0.000 (0.000) | 0.012 (0.034) | 0.028 (0.167) | 0.028 (0.167) |
| Mother:Father | 0.009 (0.096) | 0.139 (0.371) | 0.043 (0.208) | 0.116 (0.341) | 0.026 (0.161) | 0.047 (0.217) | 0.000 (0.000) | 0.000 (0.000) | 0.000 (0.000) | 0.007 (0.084) | 0.007 (0.084) |
| Pair Average Data | |||||||||||
| Fixed Effects | |||||||||||
| Intercept | 0.079 (0.026) | 0.315 (0.137) | 0.022 (0.110) | 0.102 (0.128) | 0.591 (0.150) | −0.206 (0.137) | −0.345 (0.157) | ND | ND | 0.618 (0.129) | 0.618 (0.129) |
| Genetic Distance | 5.932 (3.739) | 14.958** (3.929) | 12.520* (4.589) | 41.772* (7.276) | 51.099* (8.201) | 15.325* (5.400) | 15.325* (5.400) | ||||
| Geograph. Distance | −0.199* (0.078) | −0.224* (0.083) | |||||||||
| Eco. Distance | |||||||||||
| Morph. Distance | 0.045 (0.024) | ||||||||||
| Style Distance | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- | |
| Random Effects | |||||||||||
| Phylogenetic Structure | 0.000 (0.000) | 0.000 (0.000) | 0.000 (0.000) | 0.000 (0.000) | 0.032 (0.178) | 0.004 (0.066) | 0.011 (0.105) | ND | ND | 0.034 (0.185) | 0.034 (0.185) |
Samples sizes indicated for each barrier: number of unique species pair combinations (i.e. separate reciprocals), followed by number of species pairs (i.e. pair averages). Shown coefficients for each RI barrier were included in the model of best fit (based on likelihood ratio tests), standard error in parentheses. Bold indicates significant contribution of predictor:
*
p<0.05,
**
p<0.001;
***
p<0.0001;
bold without asterisks indicates marginally significant p<0.07. (ND) not determined, as the sample size was too small to run these analyses.