Table 1 Hypotheses for biogeographic variation in body size in ectothermic organisms
Hypothesis | Environmental variable | Predicted effect on body size |
|---|---|---|
1. Heat balance | Annual mean temperature (BIO1) | Negative |
2. Temperature-size rule | Annual mean temperature (BIO1) | Negative |
3. Optimal body temperature | Annual mean temperature (BIO1) | Positive |
4. Starvation resistance | Temperature seasonality (BIO4) | Positive |
5. Growing season length | Temperature seasonality (BIO4) | Negative |
6. Water availability | Annual precipitation (BIO12) | Negative |
7. Reverse water availability | Annual precipitation (BIO12) | Positive |
8. Primary productivity | NDVIa | Positive |