7. Maternal energy budgets
We calculated yearly maternal energy budgets by subtracting energy
content of all clutches/litters (of fresh eggs) from energy budget of
non-reproductive females:
\(V_{m}=E_{m0}+E_{m}-\sum_{i=1}^{n}E_{e}\) [Function 2]
where n was the reproductive frequency (number of clutches/litters)
through a year, Em0 was the initial energy storage of
mother, Em was the summed energy budget of mother from
the first to the last hour of the year, Ee was the
energy content of a clutch of fresh eggs.
Because viviparous mothers carry their embryos longer than do oviparous
mothers (an additional 2/3 of development), and experience metabolic
increment due to pregnancy during this period, we subtract this
increased metabolic cost from viviparous yearly maternal energy budgets
(Table S1). We average all results across 1980-2000 and 2080-2100
respectively as results for the past and the future.