Temporal Transcriptomic Profilling of Mitochondrial and Flagellar Genes During Spermatogenesis in Bombus terrestris Drones

This study aimed to elucidate the molecular mechanisms underlying spermatogenesis in male bumblebees (Bombus terrestris), a critical determinant of reproductive competence and pollination success. By conducting time-series RNA sequencing of drone testes at three developmental stages (Days 1, 5, and 9 post-eclosion), we characterized dynamic transcriptional programs associated with mitochondrial metabolism, flagellar formation, and cytoskeletal remodeling. The identification of 620 temporally regulated differentially expressed genes (DEGs), including metabolic enzymes and structural components such as inositol 2-dehydrogenase, glucose dehydrogenase, and dynein axonemal intermediate chains, reveals stage-specific coordination of energy production and motility acquisition. These findings provide foundational insight into drone reproductive maturation and offer transcriptomic markers relevant to selective breeding and pollinator management strategies.