E assumption of an underlying probability distribution [52]. Comparison of two survival curves was done by using a statistical hypothesis test called the log rank test. It is used to testDiscussionThe findings of this study demonstrate the importance of food availability at the larval stage on ability of adult flies to cope withLarval Feeding Stress Tolerance in D. ananassaeFigure 1. Survival curves for desiccation resistance in males (A) and females (B) derived from either protein (? or carbohydrate (- – -) enriched medium. doi:10.1371/journal.pone.0046131.gvarious types of stress. In this study, we found a clear evidence for impact of nutrition on the ability to cope with stress as well as on the life-history traits. As larval nutrition regulates the stress resistance, our results indicate the stress tolerance and nutrition are tightly linked. Given different viability in two types of medium, we cannot rule out that not only plastic response but also selection can be involved in explaining our results.increasing osmotic pressure during desiccation by reducing the water loss from cells [53].Madrasin web Starvation ResistanceAs far as our information goes, this is first report on comparison of starvation resistance of any Drosophila species that develop on either protein or carbohydrate-enriched medium. In our study flies developed on carbohydrate enriched medium show higher starvation resistance than flies developed on protein enriched medium. Greater starvation resistance requires physiological changes which are likely to trade-off with other fitness-related traits. By reducing the amount of nutrition in particular protein (yeast) offered to adult flies (caloric restriction) increases their starvation resistance, with up to twofold difference between females previously fed ad labium yeast than those given no yeast [54,55,56,57,58]. Sisodia and Singh [26] also found that south Indian LY-2409021 biological activity populations of Drosophila ananassae, which feed on carbohydrate rich fruits, have higher starvation resistance than north Indian populations which feed on protein enriched fruits. For starvation there is good evidence that an increase in the lipid content of adults underlies increased resistance to starvation.Desiccation ResistanceTolerance to desiccation stress was highest in flies developed on the protein enriched medium. Our results support the findings of Anderson et al. [49], where Drosophila melanogaster flies developed on protein diet show higher survival in desiccation stress. Our findings also strongly support our previous report [26] in which south Indian populations of Drosophila ananassae mostly feed on carbohydrate rich food and have low desiccation stress as compared to north Indian populations which feed on protein rich diet. The composition of food may vary with latitude and altitude of origin of population too. The possible explanation for high desiccation tolerance is that the metabolic end product from protein metabolization, uric acid had a protecting effect on theFigure 2. Survival curves for starvation resistance in males (A) and females (B) derived from either protein (? or carbohydrate (- – -) enriched medium. doi:10.1371/journal.pone.0046131.gLarval Feeding Stress Tolerance in D. ananassaeFigure 3. Survival curves for chill-coma recovery in males (A) and females (B) 
derived from either protein (? or carbohydrate (- – -) enriched medium. doi:10.1371/journal.pone.0046131.gThere are several factors which contribute to starvation resistance alt.E assumption of an underlying probability distribution [52]. Comparison of two survival curves was done by using a statistical hypothesis test called the log rank test. It is used to testDiscussionThe findings of this study demonstrate the importance of food availability at the larval stage on ability of adult flies to cope withLarval Feeding Stress Tolerance in D. ananassaeFigure 1. Survival curves for desiccation resistance in males (A) and females (B) derived from either protein (? or carbohydrate (- – -) enriched medium. doi:10.1371/journal.pone.0046131.gvarious types of stress. In this study, we found a clear evidence for impact of nutrition on the ability to cope with stress as well as on the life-history traits. As larval nutrition regulates the stress resistance, our results indicate the stress tolerance and nutrition are tightly linked. Given different viability in two types of medium, we cannot rule out that not only plastic response but also selection can be involved in explaining our results.increasing osmotic pressure during desiccation by reducing the water loss from cells [53].Starvation ResistanceAs far as our information goes, this is first report on comparison of starvation resistance of any Drosophila species that develop on either protein or carbohydrate-enriched medium. In our study flies developed on carbohydrate enriched medium show higher starvation resistance than flies developed on protein enriched medium. Greater starvation resistance requires physiological changes which are likely to trade-off with other fitness-related traits. By reducing the amount of nutrition in particular protein (yeast) offered to adult flies (caloric restriction) increases their starvation resistance, with up to twofold difference between females previously fed ad labium yeast than those given no yeast [54,55,56,57,58]. Sisodia and Singh [26] also found that south Indian populations of Drosophila ananassae, which feed on carbohydrate rich fruits, have higher starvation resistance than north Indian populations which feed on protein enriched fruits. For starvation there is good evidence that an increase in the lipid content of adults underlies increased resistance to starvation.Desiccation ResistanceTolerance to desiccation stress was highest in flies developed on the protein enriched medium. Our results support the findings of Anderson et al. [49], where Drosophila melanogaster flies developed on protein diet show higher survival in desiccation stress. Our findings also strongly support our previous report [26] in which south Indian populations of Drosophila ananassae mostly feed 
on carbohydrate rich food and have low desiccation stress as compared to north Indian populations which feed on protein rich diet. The composition of food may vary with latitude and altitude of origin of population too. The possible explanation for high desiccation tolerance is that the metabolic end product from protein metabolization, uric acid had a protecting effect on theFigure 2. Survival curves for starvation resistance in males (A) and females (B) derived from either protein (? or carbohydrate (- – -) enriched medium. doi:10.1371/journal.pone.0046131.gLarval Feeding Stress Tolerance in D. ananassaeFigure 3. Survival curves for chill-coma recovery in males (A) and females (B) derived from either protein (? or carbohydrate (- – -) enriched medium. doi:10.1371/journal.pone.0046131.gThere are several factors which contribute to starvation resistance alt.
