Compensatory reactions of populations to stresses, and their evolutionary significance.

Abstract

Cultures of Lucilia cuprina which were subjected to different kinds and intensities of stress automatically accommodated themselves to these stresses and maintained themselves in a state of balance under all the varied environmental conditions provided. Compensatory reaction always counteracted in some degree the adverse effects of the stresses to which the insects were subjected. Thus the persistent destruction of a particular age-group always caused more individuals to reach this age, so reducing the effects produced by destruction upon population density. It is shown that density governed compensatory reaction is a necessary counterpart of selection in evolutionary progress.