A delayed wave of death from reproduction in Drosophila

Mortality rates typically increase rapidly at the onset of aging but can de celerate at Later ages. Reproduction increases the death rate in many organ isms. To test the idea that a delayed impact of earlier reproduction contri butes to both an increase in death rates and a Later deceleration in mortal ity, the timing of the surplus mortality produced by an increased Level of egg production was measured in female Drosophila. Reproduction produced a d elayed wave of mortality, coincident with the sharp increase in death rates at the onset of aging and the subsequent deceleration of mortality. These results suggest that aging has evolved primarily because of the damaging ef fects of reproduction earlier in Life, rather than because of mutations tha t have detrimental effects only at Late ages.