The Role of Developmental and Adult Diets in Modulating Reproductive Senescence: Insights from Drosophila melanogaster

Abstract

Several studies have reported greater reproductive output in populations reared in rich developmental diets; while, several other studies have reported lower reproductive ability in populations reared in rich developmental diets, as compared to populations reared in poor developmental diets. I attempt to resolve this ongoing debate by highlighting the age-dependent effect of developmental diet on reproductive output. My results clearly demonstrate that the populations reared in rich developmental diet have greater reproductive output in early-life, but lesser reproductive output in mid-life as compared to populations reared in poor developmental diet. I also find that there is a gradual shift from reproductive output being affected only by developmental diet in very-early-life to reproductive output being affected by both developmental and adult diets in early-life and mid-life to reproductive output being affected only by adult diet in late-life. I also find that although the number of viable progeny produced is dependent on the effect of both developmental and adult diets across age, the various physiological processes involved in egg production are not necessarily dependent on both the diets. Specifically, the number of ovarioles and the total number of egg chambers are dependent only on developmental diet; while, ovary size and the proportion of egg chambers that undergo vitellogenesis are dependent on both developmental and adult diets, and vary with age. These results address some of the key conflicts that exist in literature about the effect of developmental diets on adult reproductive output and highlight the importance of measuring adult traits in an age-specific manner.