Experimental Studies on the Duration of Life. I. Introductory Discussion of the Duration of Life in Drosophila

This paper is the first in a series of experimental studies on the factors influencing the duration of life in Drosophila melanogaster. An account of the experimental technique used in these duration of life studies is presented. Four complete life tables for Drosophila are given, and it is shown that this organism follows quantitatively the same general law in respect of the distribution of its mortality as does man. As this work deals only with the duration of imaginal life in Drosophila there is no component in the life tables corresponding to the mortality of infancy and childhood in man. It is shown that there are wide differences in duration of life in different stocks of Drosophila, and that the basis of these differences is hereditary and not environmental. The Drosophila survival line of the life table (lx) runs in general throughout its course between human survival lines of (a) the present time, and (b) about the beginning of the Christian era (Macdonell's data from Roman Africa), the curves being superposed on the basis of the omission of the human mortality of infancy and childhood.