Polishchuk L V, Tseĭtlin V B
Department of General Ecology, Biological Faculty, M.V. Lomonosov Moscow State University, Moscow 119899, Russia.
Zh Obshch Biol. 2001 Jan-Feb;62(1):3-24.
The negative relationship between population density and body mass with the body mass exponent of -0.75 implies that the energy flow through populations of small- and large-bodied species is the same, for individual metabolism scales to body mass raised to the power of +0.75. This relationship called the energetic equivalence rule, has often been observed for mammal species assemblages studied at regional scales. Here we suggest a demography-based mechanism that may generate it. Having analyzed about 130 literature sources, mostly in Russian, we collected demography and body-mass data for 88 mammalian species from the territory and coastal waters of the former Soviet Union. The data were used to construct a number of interspecific relationships. It is shown that (1) the number of offspring per lifetime is approximately inversely proportional to the relative mass at birth (the exponent is not significantly different from -1), (2) the average lifespan is proportional to body mass to the 0.25 power, (3) body mass at birth is proportional to the adult body mass. We develop a simple theory to demonstrate that relations (1) to (3) entail the energetic equivalence rule. The theory also allows us to explain violation of this rule (in non-flying birds, for example), namely, to predict the exponent of relation (1) for any given exponent of the relation between population density and body mass. This is possible because relations (2) and (3) are likely to more universally hold than relation (1). Finally, since natural selection acts on individual traits rather than on population-level ones such as population density, the theory opens up the way to an evolutionary explanation for the energetic equivalence rule.
种群密度与体重之间呈负相关，体重指数为-0.75，这意味着通过小型和大型物种种群的能量流是相同的，因为个体新陈代谢与体重的0.75次幂成正比。这种关系被称为能量等效规则，在区域尺度上研究的哺乳动物物种组合中经常被观察到。在这里，我们提出了一种基于种群统计学的机制，它可能会产生这种规则。在分析了约130篇文献来源（大多为俄语）后，我们收集了前苏联领土及沿海水域88种哺乳动物的种群统计学和体重数据。这些数据被用于构建一些种间关系。结果表明：（1）每一生的后代数量与出生时的相对体重大致成反比（指数与-1没有显著差异）；（2）平均寿命与体重的0.25次幂成正比；（3）出生时的体重与成年体重成正比。我们发展了一个简单的理论来证明关系（1）至（3）蕴含能量等效规则。该理论还使我们能够解释这种规则的违背情况（例如在不会飞的鸟类中），即预测对于种群密度与体重之间任何给定关系指数的关系（1）的指数。这是可能的，因为关系（2）和（3）可能比关系（1）更普遍成立。最后，由于自然选择作用于个体特征而非种群水平的特征（如种群密度），该理论为能量等效规则开辟了一条进化解释的道路。
