Centre of Geometric Biology, School of Biological Sciences, Monash University, Melbourne, VIC, 3800, Australia.
Ecol Lett. 2019 Sep;22(9):1407-1416. doi: 10.1111/ele.13326. Epub 2019 Jun 17.
Body size often strongly covaries with demography across species. Metabolism has long been invoked as the driver of these patterns, but tests of causal links between size, metabolism and demography within a species are exceedingly rare. We used 400 generations of artificial selection to evolve a 2427% size difference in the microalga Dunaliella tertiolecta. We repeatedly measured size, energy fluxes and demography across the evolved lineages. Then, we used standard metabolic theory to generate predictions of how size and demography should covary based on the scaling of energy fluxes that we measured. The size dependency of energy remained relatively consistent in time, but metabolic theory failed to predict demographic rates, which varied unpredictably in strength and even sign across generations. Classic theory holds that size affects demography via metabolism - our results suggest that both metabolism and size act separately to drive demography and that among-species patterns may not predict within-species processes.
体型通常在物种间与种群动态强烈相关。长期以来，代谢被认为是导致这些模式的驱动力，但在一个物种内测试体型、代谢和种群动态之间的因果联系极为罕见。我们使用 400 代的人工选择，使微藻杜氏盐藻的体型差异进化了 2427%。我们反复测量了进化谱系的大小、能量通量和种群动态。然后，我们使用标准代谢理论，根据我们测量的能量通量的比例，生成了关于体型和种群动态应该如何相关的预测。能量的体型依赖性在时间上相对稳定，但代谢理论未能预测人口增长率，这些增长率在几代之间的强度甚至符号上都不可预测地变化。经典理论认为，体型通过代谢影响种群动态——我们的结果表明，代谢和体型都单独作用于驱动种群动态，并且种间模式可能无法预测种内过程。
