Integrated respirometry and metabolomics unveil circadian metabolic dynamics in Drosophila

Sleep and circadian rhythms shape organismal energy patterns, but how this timing connects to oxygen use and carbon dioxide production remains incompletely understood. We combined high-resolution respirometry with liquid chromatography-mass spectrometry (LC-MS)-based metabolomics to characterize respiratory dynamics and metabolic states in Drosophila melanogaster , resolving genotype-specific impacts of sleep disruption and circadian regulation. Wild-type flies under light-dark cycles (WT-LD) showed rhythmic respiratory patterns reflective of anticipatory coordination of mitochondrial energy metabolism, amino acid turnover, and redox cycling. Short-sleep mutants ( fmn , sss ) exhibited elevated metabolic rates, with reactive shifts of fuel preferences toward lipid and amino acid catabolism, and altered mitochondrial respiration. The clock mutant ( per 01 ) and flies under constant darkness (WT-DD) showed reactive and widespread metabolic dysregulation and impaired redox homeostasis. These findings demonstrate that both sleep and circadian systems contribute to aligning metabolic substrate selection with energy demands, offering mechanistic insights into how disruptions in behavioral states compromise metabolic health.