Inositol’s role in queen differentiation and reproductive fitness in the honey bee (Apis mellifera)

In Apis mellifera, caste determination and queen reproductive capacity are tightly linked to larval nutrition. During early development, nutrient provisioning by nurse bees activates endocrine and molecular signaling cascades that establish ovary structure, germline cell number, and long-term fertility. However, the role of specific micronutrients in regulating these gene networks remains largely uncharacterized. Inositol, a sugar alcohol naturally present in royal jelly and pollen, is a strong candidate due to its established roles in insulin-like signaling, oogenesis, and oxidative stress regulation across insect systems. Yet, its function in honey bee queen development has not been experimentally tested. This project investigates whether inositol supplementation during the queen’s caste-determining window modulates gene expression in reproductive tissue and enhances physiological markers of fertility. RNA sequencing of ovary tissue revealed distinct gene expression profiles in supplemented individuals, indicating that inositol influences transcriptional programs associated with reproductive function. We employed a multi-level experimental design to: (1) characterize transcriptomic changes in queen ovaries using RNA-seq, (2) assess post-mating oviposition performance as a functional reproductive phenotype, and (3) validate nurse-mediated inositol delivery via targeted MS/MS of hypopharyngeal glands. This research connects early transcriptional modulation to adult reproductive traits, advancing our understanding of how micronutrient signaling affects endocrine and developmental pathways. These findings contribute to foundational research in insect developmental genetics and support applied strategies to improve honey bee queen quality and colony resilience.