Specific metabolic rate, longevity and "Rubner constant" for birds
Zoological Institute, Russian Academy of Sciences 199034 St. Petersburg, Universitetskaya Emb.. 1, Russia
e-mail: model@zin.ru
An assumption was made that age constituent αxβ of mortality of individuals in a population in Weibull equation mx=m0+αxβ (Ricklefs, 2000) reflects change of specific metabolic rate of one individual with age. Based upon that hypothesis a formula was proposed for relationship of specific metabolic rate of an adult individual after cessation of growth, when mass W is attained, and age t: q(t)=q0(1-ωβ+1tβ) where q0=αW-b is value q(t) at the moment of growth cessation and ω=α1/(β+1) is "ageing rate", determined and estimated by R. Ricklefs. Maximum longevity of an individual was determined as tmax=(1-qcrit/q0)1/β/(ω1+1/β) where qcrit is specific metaabolic rate at the age. Parameter β and relationships ω(W) and (qcrit/q0)(W) were approximated for birds from data of Ricklefs. Statistical comparison of results of calculations of tmax max was carried out on the basis of the above formula and other known formulas for groups of Passeriformes and non-Passeriformes. Rubner constant Ru=∫tmaxtAq(t)dt was calculated assuming that body mass of an adult individual (W) ) is attained in the first year of life (tA= 0). Average values of 602.4 ± 2.5 kcal g-1 (n = 83) for non-Passeriformes and 963 ± 6.3 kcal g-1 (n = 41) for Passeriformes were obtained.
