Trans-generational effect of protein restricted diet on adult body and wing size of Drosophila melanogaster
Dietary Restriction (DR) via protein restriction (PR) has become an inquisitive field and has established feasible trade-offs between various fitness and behavioral traits in Drosophila melanogaster to understand lifespan or aging in a nutritionally challenged environment. However, the phenotypes of body size, weight and wing length respond according to factors such as flies genotype, environmental exposure, and parental diet. Hence, understanding the long-term effect of PR on these phenotypes is essential. Here, we demonstrate the effect of PR diet on body size, weight and normal & dry wing length of flies subjected to PR50 and PR70 (50% and 70% protein content present in control food respectively) for 20 generations from pre-adult stage. We found that PR fed flies have lower body weight, relative water content (in males), unaltered (PR50%) and higher (PR70%) relative fat content in males, smaller normal and dry body size as compared to control and generations 1 and 2. Interestingly, wing size and pupal size of PR flies are smaller and showed significant effects of diet and generation. Thus, these traits are sex and generation dependent along with an interaction of diet, which is capable of modulating these results variably. Our study suggests that trans-generational effect is more prominent in influencing these traits and wing length might not be a predictor for body size. Taken together, the trans-generational effect of PR on fitness and fitness-related traits might be helpful to understand the underpinning mechanisms of evolution and aging in fruit flies D. melanogaster. Summary statementTwenty generations of protein restricted diet have a diet and generation dependent effect on adult body size, wing length and body weight.