Age Invariant of Gompertz Function and Exponential Decay of Populations Commensuration with CLOV Experiments

The exponential decay law of populations is further examined on the basis of new observations of Japanese and Swedish cohorts. It is shown that the populations decrease exponentially at higher ages in accordance with the theoretical prediction, which confirms the previous conclusion. The theory is applied to recent experiments on Mediterranean fruit flies by Carey et al., (1992, Science, 258, 457–460), the results showing that the exponential decay law holds in sufficient approximation. All the evidences accumulated so far suggest that the decay law is a general theorem. On the basis of this information, we derive a general expression that estimates the limit age as a function of population. The predicted curve is in excellent agreement with the observed limit ages in Japan.