Integrated Respirometry and Metabolomics Unveil Circadian Metabolic Dynamics in Drosophila

Precise temporal regulation of metabolism by sleep and circadian rhythms is essential for dynamic energy homeostasis, yet the link between systemic metabolism and respiratory demands remains poorly defined. We combined high-resolution respirometry with LC-MS-based metabolomics to characterize respiratory dynamics and metabolic states in Drosophila melanogaster to uncover genotype-specific impacts of sleep and circadian disruption. 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. In contrast, short-sleep mutants (fmn, sss) exhibited elevated metabolic rates and reactive shifts of fuel preferences toward lipid and amino acid catabolism and displayed signs of mitochondrial stress. Circadian-clock disrupted flies (per ⁰¹ , WT-DD) showed reactive and widespread metabolic dysregulation and impaired redox homeostasis. These findings demonstrate that both sleep and circadian systems are essential for aligning metabolic substrate selection with energy demands, offering mechanistic insights into how disruptions in behavioral states compromise metabolic health.