Table 2. Logistic regression models evaluated as possible fits to infection status (0 = infected, 1 = uninfected) of tracked frogs. All possible one, two, and three-variable main-effects only models involving species identity (Species), gender of the individual (Sex), season (summer/wet season or winter/dry season, Season), and the proportion of body temperatures measured for each individual that were greater than 25°C (PA25) were considered. Models including more than three main effects or interactions were not included to preclude overfitting. The three best fitting models, with a total Akaike weight of 0.705, were averaged to obtain the final model. Predictions of this model appear in Figure 2.
| Initial models | ||||
|---|---|---|---|---|
| Effects in model | AICc | Delta AICc | Akaike weight | Nagelkerke R2 |
| Sex, Species, PA25 | 94.930 | 0.000 | 0.398 | 0.264 |
| Species, PA25 | 96.507 | 1.577 | 0.181 | 0.215 |
| Sex, Species | 97.237 | 2.307 | 0.126 | 0.206 |
| Species, Sex, Season | 98.098 | 3.168 | 0.082 | 0.223 |
| Season, Species, PA25 | 98.632 | 3.702 | 0.063 | 0.216 |
| PA25 | 99.366 | 4.436 | 0.043 | 0.119 |
| Sex, PA25 | 99.683 | 4.753 | 0.037 | 0.144 |
| Sex, Season, PA25 | 101.057 | 6.127 | 0.019 | 0.155 |
| Season, PA25 | 101.150 | 6.220 | 0.018 | 0.124 |
| Species, Season | 101.459 | 6.529 | 0.015 | 0.149 |
| Species | 102.090 | 7.160 | 0.011 | 0.111 |
| Sex | 104.602 | 9.672 | 0.003 | 0.045 |
| Sex, Season | 104.794 | 9.864 | 0.003 | 0.072 |
| Season | 104.944 | 10.014 | 0.003 | 0.040 |
*coefficients structurally set to zero; †one-tailed P value due to pre-existing hypothesis regarding effect direction (higher PA25 should decrease P(infection)).