International audienceIn spite of the extensive knowledge of the biology and the genetics of Drosophila melanogaster, the mechanisms by which this fly builds up cold tolerance remain poorly understood. Recent studies have reported that acclimation-mediated acquisition of cold tolerance is associated with moderate accumulation of sugars in drosophilids. However, it is not known whether there is a genuine causative link between cold tolerance and body sugar accumulation in Drosophila flies. We thus tested whether increasing body sugars levels, via dietary enrichment, will promote the cold tolerance of D. melanogaster adults. We gradually augmented the concentration of four different sugars (sucrose, fructose, glucose and trehalose) in rearing diets and tested the basal cold tolerance (acute and chronic). Using SIM-GC/MS approach, we verified whether feeding of larvae and adults on sugar-enriched diets was associated with increasing body sugars. We also tested whether development, body mass, fat stores, metabolites composition and metabolic pathways were altered by these dietary manipulations. The data confirm an effective incorporation of all sugars. Contrary to the expectation, cold tolerance was negatively affected by exogenous sugars, especially when supplemented at high concentrations. Rearing on high-sugar doses induced system-wide metabolic alteration associated with carbohydrate metabolism imbalance, a developmental delay and a fresh mass reduction. Our data show that high dietary sugars create a metabolic imbalance and negatively affect cold tolerance. This study provides an intriguing connection between nutritional conditions and thermal trait. It also underlines that careful attention should be given to dietary factors when studying thermal traits

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