Dopamine production in the central nervous system is important for follicle survival and interacts with genetic background and a high sugar diet during <i>Drosophila</i> oogenesis

Unhealthy diets, obesity, and low fertility are associated in Drosophila and humans. We previously showed that a high sugar diet, but not obesity, reduces Drosophila female fertility owing to increased death of newly formed germline cysts and vitellogenic follicles. Drosophila strains carrying mutations in the yellow (y) and white (w) pigmentation genes are routinely used for investigating the effects of high sugar diets, but it has remained unclear how this genetic background interacts with high sugar. Here, we show that the loss of y function is responsible for the high sugar diet-induced death of early germline cysts and vitellogenic follicles previously observed in y w mutant females. Dopamine supplementation prevents follicle death in y mutants on a high sugar diet. Conversely, severe dopamine imbalance or lack of dopamine production in the central nervous system causes follicle death regardless of diet or genetic background, while early germline cyst survival does not depend on dopamine. Our findings are broadly relevant to our understanding of how the effects of unhealthy diets might differ depending on genetic factors and highlight a key connection between dopamine metabolism in the central nervous system and ovarian follicle survival.