The linear alometric relationship between total metabolic energy per life span and body mass of poikilothermic animals

Abstract

A linear relationship exists between total metabolic energy per life span PT ls (kJ) and body mass M (kg) of 54 poikilothermic species (Protozoa, Nematoda, Mollusca, Asteroidae, Insecta, Arachnoidae, Crustacea, Pisces, Amphibia, Reptilia and Snakes): PT ls = A ls * M 1.0838, where P (kJ/day) is the rate of metabolism and T ls (days) is the life span of animals. The linear coefficient A ls * = 3.7 × 10 5 kJ/kg is the total metabolic energy, exhausted during the life span per 1 kg body mass of animals. This linear coefficient can be regarded as relatively constant metabolic parameter for poikilothermic organisms, ranging from 0.1 × 10 5 to 5.5 × 10 5 kJ/kg, in spite of 17-degree differences between metabolic rate and body mass of animals. A linear relationship between total metabolic energy per life span and body mass of only 48 poikilothermic multicellular animals (without Protozoa) is: PT ls = A ls * M 0.9692 with linear coefficient A ls * = 2.34 × 10 5 kJ/kg. Since a power relationship exists between the rate of metabolism and body mass of animals of the type: P = aM k ( a and k are the alometric constants), an empiric rule could be formulated, that life span is a time interval for which the total metabolic energy per life span becomes proportional to body mass of animals and power coefficient k becomes ≈1.0.