Table 1.
The linear and nonlinear effects of daily protein (P) and carbohydrate (C) intake on the lifespan (LS) and daily reproductive effort (DRE) of (A) female and (B) male T. commodus with and without dl-alpha-tocopherol supplementation. Significant effects are highlighted in bold.
| Non-Supplemented | Supplemented | |||||
|---|---|---|---|---|---|---|
| Coefficient * ± SE | Prop | p Value | Coefficient ± SE | Prop | p Value | |
| (A): Females | ||||||
| LS | ||||||
| P | −0.159 ± 0.171 | 0.181 | 0.362 | −0.095 ± 0.183 | 0.695 | 0.610 |
| C | 0.486 ± 0.159 | 0.998 | 0.004 | 0.271 ± 0.126 | 0.019 | 0.038 |
| P × P | −0.258 ± 0.198 | 0.102 | 0.203 | −0.350 ± 0.201 | 0.953 | 0.094 |
| C × C | −0.374 ± 0.176 | 0.021 | 0.042 | −0.307 ± 0.144 | 0.018 | 0.039 |
| P × C | −0.283 ± 0.266 | 0.853 | 0.295 | −0.661 ± 0.276 | 0.012 | 0.023 |
| DRE | ||||||
| P | 0.192 ± 0.165 | 0.125 | 0.250 | 0.139 ± 0.196 | 0.758 | 0.484 |
| C | 0.280 ± 0.133 | 0.022 | 0.042 | 0.678 ± 0.168 | 0.001 | 0.002 |
| P × P | −0.187 ± 0.083 | 0.016 | 0.031 | −0.416 ± 0.193 | 0.018 | 0.037 |
| C × C | −0.145 ± 0.126 | 0.129 | 0.259 | −0.204 ± 0.194 | 0.851 | 0.298 |
| P × C | 0.179 ± 0.262 | 0.751 | 0.498 | −0.260 ± 0.291 | 0.810 | 0.379 |
| (B): Males | ||||||
| LS | ||||||
| P | 0.521 ± 0.202 | 0.994 | 0.013 | 0.511 ± 0.193 | 0.995 | 0.010 |
| C | 0.961 ± 0.302 | 0.002 | 0.003 | 0.767 ± 0.227 | 0.001 | 0.002 |
| P × P | −0.422 ± 0.290 | 0.912 | 0.176 | −0.137 ± 0.277 | 0.689 | 0.622 |
| C × C | −0.635 ± 0.480 | 0.905 | 0.191 | −0.224 ± 0.322 | 0.245 | 0.490 |
| P × C | −0.379 ± 0.468 | 0.785 | 0.430 | −0.292 ± 0.453 | 0.737 | 0.526 |
| DRE | ||||||
| P | −0.023 ± 0.257 | 0.536 | 0.928 | 0.170 ± 0.276 | 0.729 | 0.543 |
| C | 0.086 ± 0.317 | 0.605 | 0.790 | 0.354 ± 0.149 | 0.021 | 0.043 |
| P × P | −0.126 ± 0.308 | 0.659 | 0.683 | −0.201 ± 0.334 | 0.274 | 0.549 |
| C × C | −0.935 ± 0.421 | 0.017 | 0.033 | −0.064 ± 0.388 | 0.565 | 0.870 |
| P × C | −0.858 ± 0.676 | 0.106 | 0.212 | −0.060 ± 0.547 | 0.543 | 0.914 |
* The linear regression coefficients (i.e., P and C) describe the linear slope of the relationship between nutrient intake and the response variable, whereas the quadratic regression coefficients (i.e., P × P and C × C) describes the curvature of this relationship, with a negative coefficient indicating a convex relationship (i.e., a peak on the response surface) and a positive coefficient indicating a concave relationship (i.e., a trough on the response surface). The correlational regression coefficients (i.e., P × C) describe how the covariance between the two nutrients influences the response variable, with a negative coefficient indicating that a negative covariance between nutrients increases the response variable and a positive coefficient indicating that a positive covariance between nutrients increases the response variable. Full details of this approach are provided in Lande and Arnold [41]. “p value” is the significance value and “prop” is the proportion of times out of 10,000 that the shuffled gradient exceeds the normal gradient, for discussion please see the Methods section.