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

A linear relationship exists between total metabolic energy per life span PTls, (U) and body mass M (kg) of 54 poikilothermic species (Protozoa, Nematoda, Mollusca, Asteroidae, Insecta, Arachnoidae, Crustacea, Pisces, Amphibia, Reptilia and Snakes): PTls = 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 x 10(5) kJ/kg is the total metabolic energy, exhausted during the life span per I kg body mass of animals. This linear coefficient can be regarded as relatively constant metabolic parameter for poikilothermic organisms, ranging from 0.1 X 10(5) to 5.5 x 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: PTls = A(ls)*M-0.9692 with linear coefficient A(ls)* = 2.34 x 10(5) kJ/kg. Since a power relationship exists between the rate of metabolism Is 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 approximate to 1.0. (c) 2005 Elsevier Ireland Ltd. All rights reserved.