3. Maternal energy budgets
In 1980-2000, the maternal energy budgets of viviparous species are projected to have been higher than those of oviparous species in most regions (Fig. 5a, c). Maternal energy budgets of viviparous species were estimated to have been relatively high at lower latitudes and elevations, while oviparous mothers had low energy budgets (<50 KJ) at sites where clutch numbers are high (sites with low latitudes and elevations; see Fig. 3a). We estimate that climate change generally decreases the energy budgets of oviparous mothers at mid-low latitudes (except for some sites with high elevations; decreases by -11.3% on average) (Fig. 5b). On the contrary, energy budgets of viviparous mothers increase (by 21.2% on average) at most regions (Fig. 5d).
Under climate change, oviparous mothers would have a larger decrement in energy budget as they produce more clutches (Fig. 5e). On the other hand, viviparous mothers would have larger increment of energy budget when they have a larger decrement in cost of prolonged gestation (Fig. 5f), while the slope of this correlation is steeper at regions with no increment in litter numbers (blue points).