Data in support of "Metabolic loads and the costs of metazoan reproduction"

Reproduction includes two energy investments—the energy in the offspring and the energy expended to make them. The former is well understood, whereas the latter is unquantified but often assumed to be small. Without understanding both investments, the true energy costs of reproduction are unknown. We present a framework for estimating the total energy costs of reproduction by combining data on the energy content of offspring (direct costs) and the metabolic load of bearing them (indirect costs). We find that direct costs typically represent the smaller fraction of the energy expended on reproduction. Mammals pay the highest reproductive costs (excluding lactation), ~90% of which are indirect. Ectotherms expend less on reproduction overall, and live-bearing ectotherms pay higher indirect costs compared with egg-layers. We show that the energy demands of reproduction exceed standard assumptions.

繁殖过程包含两类能量投入：子代自身携带的能量，以及产出子代所消耗的能量。前者的相关研究已较为充分，而后者虽尚未被量化，但通常被认为占比极小。若未能同时明晰这两类投入，便无法确知繁殖行为的真实能量成本。本研究提出一套估算繁殖总能量成本的分析框架，通过整合子代能量含量（直接成本）与孕育子代的代谢负荷（间接成本）相关数据实现。研究发现，直接成本通常仅占繁殖总能量消耗的较小部分。哺乳动物承担着最高的繁殖能量成本（不包括泌乳环节），其中约90%为间接成本。变温动物（ectotherms）整体的繁殖能量消耗更低，且与卵生变温动物相比，胎生变温动物的间接繁殖成本更高。本研究证实，繁殖行为的能量需求远超现有标准假设水平。