Identical  optimization models of life history based on 
different fitness measures:
a  simple example with an important message

L. Pasztor, G. Meszena and E. Kisdi

Summary

As this simple example shows, contrary to the common misbelive,
the optimal age of maturity may be affected also by the early
juvenile mortality in a stable population. The comparison of
the results of optimization in stable and growing population is 
meaningless without the specification of the form of density 
dependence in the former one. Such optimality models which
are based on the maximization of r or R0 but ignore density
dependence, can be compared only if one considers the following 
conditions:
1. Models with r can be interpreted either as
a. ones which concern populations that grow exponentially, or
b. ones which concern stable populations with special assumptions
on the way of population regulation.
2. Models with R0 can refer only to populations in ecological 
equilibrium with such density dependence which usually differs 
from the one asumed in case of r.
Our most important message says, that it is possible to find 
more than one appropriate measure of fitness under a given set 
of conditions. However, if the results seem to be different do 
not blame the fitness measure but make the dependence of the 
optimum on the environment mathematically explicit and do not
ignore density dependence!